diff options
37 files changed, 1722 insertions, 409 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index aacccb376c28..aa1321fdc300 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3781,6 +3781,20 @@ F: include/linux/blk* F: kernel/trace/blktrace.c F: lib/sbitmap.c +BLOCK LAYER DEVICE DRIVER API [RUST] +M: Andreas Hindborg <[email protected]> +R: Boqun Feng <[email protected]> +S: Supported +W: https://rust-for-linux.com +B: https://github.com/Rust-for-Linux/linux/issues +C: https://rust-for-linux.zulipchat.com/#narrow/stream/Block +T: git https://github.com/Rust-for-Linux/linux.git rust-block-next +F: drivers/block/rnull.rs +F: rust/kernel/block.rs +F: rust/kernel/block/ + BLOCK2MTD DRIVER M: Joern Engel <[email protected]> diff --git a/block/bdev.c b/block/bdev.c index 353677ac49b3..ced4ac990ec8 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -385,7 +385,7 @@ static struct file_system_type bd_type = { }; struct super_block *blockdev_superblock __ro_after_init; -struct vfsmount *blockdev_mnt __ro_after_init; +static struct vfsmount *blockdev_mnt __ro_after_init; EXPORT_SYMBOL_GPL(blockdev_superblock); void __init bdev_cache_init(void) diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index d442ee358fc2..b758693697c0 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -797,57 +797,6 @@ void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) */ bfq_link_bfqg(bfqd, bfqg); __bfq_bic_change_cgroup(bfqd, bic, bfqg); - /* - * Update blkg_path for bfq_log_* functions. We cache this - * path, and update it here, for the following - * reasons. Operations on blkg objects in blk-cgroup are - * protected with the request_queue lock, and not with the - * lock that protects the instances of this scheduler - * (bfqd->lock). This exposes BFQ to the following sort of - * race. - * - * The blkg_lookup performed in bfq_get_queue, protected - * through rcu, may happen to return the address of a copy of - * the original blkg. If this is the case, then the - * bfqg_and_blkg_get performed in bfq_get_queue, to pin down - * the blkg, is useless: it does not prevent blk-cgroup code - * from destroying both the original blkg and all objects - * directly or indirectly referred by the copy of the - * blkg. - * - * On the bright side, destroy operations on a blkg invoke, as - * a first step, hooks of the scheduler associated with the - * blkg. And these hooks are executed with bfqd->lock held for - * BFQ. As a consequence, for any blkg associated with the - * request queue this instance of the scheduler is attached - * to, we are guaranteed that such a blkg is not destroyed, and - * that all the pointers it contains are consistent, while we - * are holding bfqd->lock. A blkg_lookup performed with - * bfqd->lock held then returns a fully consistent blkg, which - * remains consistent until this lock is held. - * - * Thanks to the last fact, and to the fact that: (1) bfqg has - * been obtained through a blkg_lookup in the above - * assignment, and (2) bfqd->lock is being held, here we can - * safely use the policy data for the involved blkg (i.e., the - * field bfqg->pd) to get to the blkg associated with bfqg, - * and then we can safely use any field of blkg. After we - * release bfqd->lock, even just getting blkg through this - * bfqg may cause dangling references to be traversed, as - * bfqg->pd may not exist any more. - * - * In view of the above facts, here we cache, in the bfqg, any - * blkg data we may need for this bic, and for its associated - * bfq_queue. As of now, we need to cache only the path of the - * blkg, which is used in the bfq_log_* functions. - * - * Finally, note that bfqg itself needs to be protected from - * destruction on the blkg_free of the original blkg (which - * invokes bfq_pd_free). We use an additional private - * refcounter for bfqg, to let it disappear only after no - * bfq_queue refers to it any longer. - */ - blkg_path(bfqg_to_blkg(bfqg), bfqg->blkg_path, sizeof(bfqg->blkg_path)); bic->blkcg_serial_nr = serial_nr; } diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 4b88a54a9b76..36a4998c4b37 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5463,40 +5463,42 @@ static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync, } } +static void _bfq_exit_icq(struct bfq_io_cq *bic, unsigned int num_actuators) +{ + struct bfq_iocq_bfqq_data *bfqq_data = bic->bfqq_data; + unsigned int act_idx; + + for (act_idx = 0; act_idx < num_actuators; act_idx++) { + if (bfqq_data[act_idx].stable_merge_bfqq) + bfq_put_stable_ref(bfqq_data[act_idx].stable_merge_bfqq); + + bfq_exit_icq_bfqq(bic, true, act_idx); + bfq_exit_icq_bfqq(bic, false, act_idx); + } +} + static void bfq_exit_icq(struct io_cq *icq) { struct bfq_io_cq *bic = icq_to_bic(icq); struct bfq_data *bfqd = bic_to_bfqd(bic); unsigned long flags; - unsigned int act_idx; + /* * If bfqd and thus bfqd->num_actuators is not available any * longer, then cycle over all possible per-actuator bfqqs in * next loop. We rely on bic being zeroed on creation, and * therefore on its unused per-actuator fields being NULL. - */ - unsigned int num_actuators = BFQ_MAX_ACTUATORS; - struct bfq_iocq_bfqq_data *bfqq_data = bic->bfqq_data; - - /* + * * bfqd is NULL if scheduler already exited, and in that case * this is the last time these queues are accessed. */ if (bfqd) { spin_lock_irqsave(&bfqd->lock, flags); - num_actuators = bfqd->num_actuators; - } - - for (act_idx = 0; act_idx < num_actuators; act_idx++) { - if (bfqq_data[act_idx].stable_merge_bfqq) - bfq_put_stable_ref(bfqq_data[act_idx].stable_merge_bfqq); - - bfq_exit_icq_bfqq(bic, true, act_idx); - bfq_exit_icq_bfqq(bic, false, act_idx); - } - - if (bfqd) + _bfq_exit_icq(bic, bfqd->num_actuators); spin_unlock_irqrestore(&bfqd->lock, flags); + } else { + _bfq_exit_icq(bic, BFQ_MAX_ACTUATORS); + } } /* diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h index 467e8cfc41a2..08ddf2cfae5b 100644 --- a/block/bfq-iosched.h +++ b/block/bfq-iosched.h @@ -1003,9 +1003,6 @@ struct bfq_group { /* must be the first member */ struct blkg_policy_data pd; - /* cached path for this blkg (see comments in bfq_bic_update_cgroup) */ - char blkg_path[128]; - /* reference counter (see comments in bfq_bic_update_cgroup) */ refcount_t ref; diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 90b3959d88cf..bd472a30bc61 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -301,19 +301,6 @@ static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd) } /** - * blkg_path - format cgroup path of blkg - * @blkg: blkg of interest - * @buf: target buffer - * @buflen: target buffer length - * - * Format the path of the cgroup of @blkg into @buf. - */ -static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen) -{ - return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); -} - -/** * blkg_get - get a blkg reference * @blkg: blkg to get * diff --git a/block/blk-integrity.c b/block/blk-integrity.c index 05a48689a424..010decc892ea 100644 --- a/block/blk-integrity.c +++ b/block/blk-integrity.c @@ -186,8 +186,8 @@ const char *blk_integrity_profile_name(struct blk_integrity *bi) } EXPORT_SYMBOL_GPL(blk_integrity_profile_name); -static ssize_t flag_store(struct device *dev, struct device_attribute *attr, - const char *page, size_t count, unsigned char flag) +static ssize_t flag_store(struct device *dev, const char *page, size_t count, + unsigned char flag) { struct request_queue *q = dev_to_disk(dev)->queue; struct queue_limits lim; @@ -213,8 +213,7 @@ static ssize_t flag_store(struct device *dev, struct device_attribute *attr, return count; } -static ssize_t flag_show(struct device *dev, struct device_attribute *attr, - char *page, unsigned char flag) +static ssize_t flag_show(struct device *dev, char *page, unsigned char flag) { struct blk_integrity *bi = dev_to_bi(dev); @@ -253,26 +252,26 @@ static ssize_t read_verify_store(struct device *dev, struct device_attribute *attr, const char *page, size_t count) { - return flag_store(dev, attr, page, count, BLK_INTEGRITY_NOVERIFY); + return flag_store(dev, page, count, BLK_INTEGRITY_NOVERIFY); } static ssize_t read_verify_show(struct device *dev, struct device_attribute *attr, char *page) { - return flag_show(dev, attr, page, BLK_INTEGRITY_NOVERIFY); + return flag_show(dev, page, BLK_INTEGRITY_NOVERIFY); } static ssize_t write_generate_store(struct device *dev, struct device_attribute *attr, const char *page, size_t count) { - return flag_store(dev, attr, page, count, BLK_INTEGRITY_NOGENERATE); + return flag_store(dev, page, count, BLK_INTEGRITY_NOGENERATE); } static ssize_t write_generate_show(struct device *dev, struct device_attribute *attr, char *page) { - return flag_show(dev, attr, page, BLK_INTEGRITY_NOGENERATE); + return flag_show(dev, page, BLK_INTEGRITY_NOGENERATE); } static ssize_t device_is_integrity_capable_show(struct device *dev, diff --git a/block/blk-settings.c b/block/blk-settings.c index 008fed84edb4..b19306804056 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -80,6 +80,14 @@ static int blk_validate_zoned_limits(struct queue_limits *lim) if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED))) return -EINVAL; + /* + * Given that active zones include open zones, the maximum number of + * open zones cannot be larger than the maximum number of active zones. + */ + if (lim->max_active_zones && + lim->max_open_zones > lim->max_active_zones) + return -EINVAL; + if (lim->zone_write_granularity < lim->logical_block_size) lim->zone_write_granularity = lim->logical_block_size; @@ -298,7 +306,6 @@ int blk_set_default_limits(struct queue_limits *lim) */ int queue_limits_commit_update(struct request_queue *q, struct queue_limits *lim) - __releases(q->limits_lock) { int error; diff --git a/block/blk-zoned.c b/block/blk-zoned.c index 52abebf56027..8f89705f5e1c 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -1647,8 +1647,22 @@ static int disk_update_zone_resources(struct gendisk *disk, return -ENODEV; } + lim = queue_limits_start_update(q); + + /* + * Some devices can advertize zone resource limits that are larger than + * the number of sequential zones of the zoned block device, e.g. a + * small ZNS namespace. For such case, assume that the zoned device has + * no zone resource limits. + */ + nr_seq_zones = disk->nr_zones - nr_conv_zones; + if (lim.max_open_zones >= nr_seq_zones) + lim.max_open_zones = 0; + if (lim.max_active_zones >= nr_seq_zones) + lim.max_active_zones = 0; + if (!disk->zone_wplugs_pool) - return 0; + goto commit; /* * If the device has no limit on the maximum number of open and active @@ -1657,9 +1671,6 @@ static int disk_update_zone_resources(struct gendisk *disk, * dynamic zone write plug allocation when simultaneously writing to * more zones than the size of the mempool. */ - lim = queue_limits_start_update(q); - - nr_seq_zones = disk->nr_zones - nr_conv_zones; pool_size = max(lim.max_open_zones, lim.max_active_zones); if (!pool_size) pool_size = min(BLK_ZONE_WPLUG_DEFAULT_POOL_SIZE, nr_seq_zones); @@ -1673,6 +1684,7 @@ static int disk_update_zone_resources(struct gendisk *disk, lim.max_open_zones = 0; } +commit: return queue_limits_commit_update(q, &lim); } diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 5b9d4aaebb81..ed209f4f2798 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -354,6 +354,15 @@ config VIRTIO_BLK This is the virtual block driver for virtio. It can be used with QEMU based VMMs (like KVM or Xen). Say Y or M. +config BLK_DEV_RUST_NULL + tristate "Rust null block driver (Experimental)" + depends on RUST + help + This is the Rust implementation of the null block driver. For now it + is only a minimal stub. + + If unsure, say N. + config BLK_DEV_RBD tristate "Rados block device (RBD)" depends on INET && BLOCK diff --git a/drivers/block/Makefile b/drivers/block/Makefile index 101612cba303..1105a2d4fdcb 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -9,6 +9,9 @@ # needed for trace events ccflags-y += -I$(src) +obj-$(CONFIG_BLK_DEV_RUST_NULL) += rnull_mod.o +rnull_mod-y := rnull.o + obj-$(CONFIG_MAC_FLOPPY) += swim3.o obj-$(CONFIG_BLK_DEV_SWIM) += swim_mod.o obj-$(CONFIG_BLK_DEV_FD) += floppy.o diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c index ff45701f7a5e..49ced65bef4c 100644 --- a/drivers/block/amiflop.c +++ b/drivers/block/amiflop.c @@ -232,6 +232,7 @@ static DEFINE_MUTEX(amiflop_mutex); static unsigned long int fd_def_df0 = FD_DD_3; /* default for df0 if it doesn't identify */ module_param(fd_def_df0, ulong, 0); +MODULE_DESCRIPTION("Amiga floppy driver"); MODULE_LICENSE("GPL"); /* diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c index 4ee10a742bdb..4ba98c6654be 100644 --- a/drivers/block/ataflop.c +++ b/drivers/block/ataflop.c @@ -2200,4 +2200,5 @@ static void __exit atari_floppy_exit(void) module_init(atari_floppy_init) module_exit(atari_floppy_exit) +MODULE_DESCRIPTION("Atari floppy driver"); MODULE_LICENSE("GPL"); diff --git a/drivers/block/rnull.rs b/drivers/block/rnull.rs new file mode 100644 index 000000000000..b0227cf9ddd3 --- /dev/null +++ b/drivers/block/rnull.rs @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! This is a Rust implementation of the C null block driver. +//! +//! Supported features: +//! +//! - blk-mq interface +//! - direct completion +//! - block size 4k +//! +//! The driver is not configurable. + +use kernel::{ + alloc::flags, + block::mq::{ + self, + gen_disk::{self, GenDisk}, + Operations, TagSet, + }, + error::Result, + new_mutex, pr_info, + prelude::*, + sync::{Arc, Mutex}, + types::ARef, +}; + +module! { + type: NullBlkModule, + name: "rnull_mod", + author: "Andreas Hindborg", + license: "GPL v2", +} + +struct NullBlkModule { + _disk: Pin<Box<Mutex<GenDisk<NullBlkDevice>>>>, +} + +impl kernel::Module for NullBlkModule { + fn init(_module: &'static ThisModule) -> Result<Self> { + pr_info!("Rust null_blk loaded\n"); + let tagset = Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?; + + let disk = gen_disk::GenDiskBuilder::new() + .capacity_sectors(4096 << 11) + .logical_block_size(4096)? + .physical_block_size(4096)? + .rotational(false) + .build(format_args!("rnullb{}", 0), tagset)?; + + let disk = Box::pin_init(new_mutex!(disk, "nullb:disk"), flags::GFP_KERNEL)?; + + Ok(Self { _disk: disk }) + } +} + +struct NullBlkDevice; + +#[vtable] +impl Operations for NullBlkDevice { + #[inline(always)] + fn queue_rq(rq: ARef<mq::Request<Self>>, _is_last: bool) -> Result { + mq::Request::end_ok(rq) + .map_err(|_e| kernel::error::code::EIO) + // We take no refcounts on the request, so we expect to be able to + // end the request. The request reference must be unique at this + // point, and so `end_ok` cannot fail. + .expect("Fatal error - expected to be able to end request"); + + Ok(()) + } + + fn commit_rqs() {} +} diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c index 7c5f4e4d9b50..4b7219be1bb8 100644 --- a/drivers/block/z2ram.c +++ b/drivers/block/z2ram.c @@ -409,4 +409,5 @@ static void __exit z2_exit(void) module_init(z2_init); module_exit(z2_exit); +MODULE_DESCRIPTION("Amiga Zorro II ramdisk driver"); MODULE_LICENSE("GPL"); diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index abe88d1e6735..052c00c1eb15 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -3542,7 +3542,7 @@ static void raid_status(struct dm_target *ti, status_type_t type, recovery = rs->md.recovery; state = decipher_sync_action(mddev, recovery); progress = rs_get_progress(rs, recovery, state, resync_max_sectors); - resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ? + resync_mismatches = mddev->last_sync_action == ACTION_CHECK ? atomic64_read(&mddev->resync_mismatches) : 0; /* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */ diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 502ebc78d490..92d18dcdb3e9 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1829,12 +1829,9 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, if (dm_table_any_dev_attr(t, device_dax_write_cache_enabled, NULL)) dax_write_cache(t->md->dax_dev, true); - /* - * For a zoned target, setup the zones related queue attributes - * and resources necessary for zone append emulation if necessary. - */ + /* For a zoned table, setup the zone related queue attributes. */ if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) && - (limits->features & limits->features & BLK_FEAT_ZONED)) { + (limits->features & BLK_FEAT_ZONED)) { r = dm_set_zones_restrictions(t, q, limits); if (r) return r; @@ -1844,6 +1841,17 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, if (r) return r; + /* + * Now that the limits are set, check the zones mapped by the table + * and setup the resources for zone append emulation if necessary. + */ + if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) && + (limits->features & BLK_FEAT_ZONED)) { + r = dm_revalidate_zones(t, q); + if (r) + return r; + } + dm_update_crypto_profile(q, t); return 0; } diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c index 88d313229b43..4d37e53b50ee 100644 --- a/drivers/md/dm-zone.c +++ b/drivers/md/dm-zone.c @@ -13,8 +13,6 @@ #define DM_MSG_PREFIX "zone" -#define DM_ZONE_INVALID_WP_OFST UINT_MAX - /* * For internal zone reports bypassing the top BIO submission path. */ @@ -146,34 +144,27 @@ bool dm_is_zone_write(struct mapped_device *md, struct bio *bio) } /* - * Count conventional zones of a mapped zoned device. If the device - * only has conventional zones, do not expose it as zoned. - */ -static int dm_check_zoned_cb(struct blk_zone *zone, unsigned int idx, - void *data) -{ - unsigned int *nr_conv_zones = data; - - if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL) - (*nr_conv_zones)++; - - return 0; -} - -/* * Revalidate the zones of a mapped device to initialize resource necessary * for zone append emulation. Note that we cannot simply use the block layer * blk_revalidate_disk_zones() function here as the mapped device is suspended * (this is called from __bind() context). */ -static int dm_revalidate_zones(struct mapped_device *md, struct dm_table *t) +int dm_revalidate_zones(struct dm_table *t, struct request_queue *q) { + struct mapped_device *md = t->md; struct gendisk *disk = md->disk; int ret; + if (!get_capacity(disk)) + return 0; + /* Revalidate only if something changed. */ - if (!disk->nr_zones || disk->nr_zones != md->nr_zones) + if (!disk->nr_zones || disk->nr_zones != md->nr_zones) { + DMINFO("%s using %s zone append", + disk->disk_name, + queue_emulates_zone_append(q) ? "emulated" : "native"); md->nr_zones = 0; + } if (md->nr_zones) return 0; @@ -220,13 +211,127 @@ static bool dm_table_supports_zone_append(struct dm_table *t) return true; } +struct dm_device_zone_count { + sector_t start; + sector_t len; + unsigned int total_nr_seq_zones; + unsigned int target_nr_seq_zones; +}; + +/* + * Count the total number of and the number of mapped sequential zones of a + * target zoned device. + */ +static int dm_device_count_zones_cb(struct blk_zone *zone, + unsigned int idx, void *data) +{ + struct dm_device_zone_count *zc = data; + + if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL) { + zc->total_nr_seq_zones++; + if (zone->start >= zc->start && + zone->start < zc->start + zc->len) + zc->target_nr_seq_zones++; + } + + return 0; +} + +static int dm_device_count_zones(struct dm_dev *dev, + struct dm_device_zone_count *zc) +{ + int ret; + + ret = blkdev_report_zones(dev->bdev, 0, BLK_ALL_ZONES, + dm_device_count_zones_cb, zc); + if (ret < 0) + return ret; + if (!ret) + return -EIO; + return 0; +} + +struct dm_zone_resource_limits { + unsigned int mapped_nr_seq_zones; + struct queue_limits *lim; + bool reliable_limits; +}; + +static int device_get_zone_resource_limits(struct dm_target *ti, + struct dm_dev *dev, sector_t start, + sector_t len, void *data) +{ + struct dm_zone_resource_limits *zlim = data; + struct gendisk *disk = dev->bdev->bd_disk; + unsigned int max_open_zones, max_active_zones; + int ret; + struct dm_device_zone_count zc = { + .start = start, + .len = len, + }; + + /* + * If the target is not the whole device, the device zone resources may + * be shared between different targets. Check this by counting the + * number of mapped sequential zones: if this number is smaller than the + * total number of sequential zones of the target device, then resource + * sharing may happen and the zone limits will not be reliable. + */ + ret = dm_device_count_zones(dev, &zc); + if (ret) { + DMERR("Count %s zones failed %d", disk->disk_name, ret); + return ret; + } + + /* + * If the target does not map any sequential zones, then we do not need + * any zone resource limits. + */ + if (!zc.target_nr_seq_zones) + return 0; + + /* + * If the target does not map all sequential zones, the limits + * will not be reliable. + */ + if (zc.target_nr_seq_zones < zc.total_nr_seq_zones) + zlim->reliable_limits = false; + + /* + * If the target maps less sequential zones than the limit values, then + * we do not have limits for this target. + */ + max_active_zones = disk->queue->limits.max_active_zones; + if (max_active_zones >= zc.target_nr_seq_zones) + max_active_zones = 0; + zlim->lim->max_active_zones = + min_not_zero(max_active_zones, zlim->lim->max_active_zones); + + max_open_zones = disk->queue->limits.max_open_zones; + if (max_open_zones >= zc.target_nr_seq_zones) + max_open_zones = 0; + zlim->lim->max_open_zones = + min_not_zero(max_open_zones, zlim->lim->max_open_zones); + + /* + * Also count the total number of sequential zones for the mapped + * device so that when we are done inspecting all its targets, we are + * able to check if the mapped device actually has any sequential zones. + */ + zlim->mapped_nr_seq_zones += zc.target_nr_seq_zones; + + return 0; +} + int dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q, struct queue_limits *lim) { struct mapped_device *md = t->md; struct gendisk *disk = md->disk; - unsigned int nr_conv_zones = 0; - int ret; + struct dm_zone_resource_limits zlim = { + .reliable_limits = true, + .lim = lim, + }; /* * Check if zone append is natively supported, and if not, set the @@ -240,46 +345,55 @@ int dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q, lim->max_zone_append_sectors = 0; } - if (!get_capacity(md->disk)) - return 0; - /* - * Count conventional zones to check that the mapped device will indeed - * have sequential write required zones. + * Determine the max open and max active zone limits for the mapped + * device by inspecting the zone resource limits and the zones mapped + * by each target. */ - md->zone_revalidate_map = t; - ret = dm_blk_report_zones(disk, 0, UINT_MAX, - dm_check_zoned_cb, &nr_conv_zones); - md->zone_revalidate_map = NULL; - if (ret < 0) { - DMERR("Check zoned failed %d", ret); - return ret; + for (unsigned int i = 0; i < t->num_targets; i++) { + struct dm_target *ti = dm_table_get_target(t, i); + + if (!ti->type->iterate_devices || + ti->type->iterate_devices(ti, + device_get_zone_resource_limits, &zlim)) { + DMERR("Could not determine %s zone resource limits", + disk->disk_name); + return -ENODEV; + } } /* - * If we only have conventional zones, expose the mapped device as - * a regular device. + * If we only have conventional zones mapped, expose the mapped device + + as a regular device. */ - if (nr_conv_zones >= ret) { + if (!zlim.mapped_nr_seq_zones) { lim->max_open_zones = 0; lim->max_active_zones = 0; + lim->max_zone_append_sectors = 0; + lim->zone_write_granularity = 0; + lim->chunk_sectors = 0; lim->features &= ~BLK_FEAT_ZONED; clear_bit(DMF_EMULATE_ZONE_APPEND, &md->flags); + md->nr_zones = 0; disk->nr_zones = 0; return 0; } - if (!md->disk->nr_zones) { - DMINFO("%s using %s zone append", - md->disk->disk_name, - queue_emulates_zone_append(q) ? "emulated" : "native"); - } - - ret = dm_revalidate_zones(md, t); - if (ret < 0) - return ret; + /* + * Warn once (when the capacity is not yet set) if the mapped device is + * partially using zone resources of the target devices as that leads to + * unreliable limits, i.e. if another mapped device uses the same + * underlying devices, we cannot enforce zone limits to guarantee that + * writing will not lead to errors. Note that we really should return + * an error for such case but there is no easy way to find out if + * another mapped device uses the same underlying zoned devices. + */ + if (!get_capacity(disk) && !zlim.reliable_limits) + DMWARN("%s zone resource limits may be unreliable", + disk->disk_name); - if (!static_key_enabled(&zoned_enabled.key)) + if (lim->features & BLK_FEAT_ZONED && + !static_key_enabled(&zoned_enabled.key)) static_branch_enable(&zoned_enabled); return 0; } diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 53ef8207fe2c..c984ecb64b1e 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -103,6 +103,7 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t); */ int dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q, struct queue_limits *lim); +int dm_revalidate_zones(struct dm_table *t, struct request_queue *q); void dm_zone_endio(struct dm_io *io, struct bio *clone); #ifdef CONFIG_BLK_DEV_ZONED int dm_blk_report_zones(struct gendisk *disk, sector_t sector, diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index 0a2d37eb38ef..08232d8dc815 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -227,6 +227,8 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap, struct block_device *bdev; struct mddev *mddev = bitmap->mddev; struct bitmap_storage *store = &bitmap->storage; + unsigned int bitmap_limit = (bitmap->storage.file_pages - pg_index) << + PAGE_SHIFT; loff_t sboff, offset = mddev->bitmap_info.offset; sector_t ps = pg_index * PAGE_SIZE / SECTOR_SIZE; unsigned int size = PAGE_SIZE; @@ -269,11 +271,9 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap, if (size == 0) /* bitmap runs in to data */ return -EINVAL; - } else { - /* DATA METADATA BITMAP - no problems */ } - md_super_write(mddev, rdev, sboff + ps, (int) size, page); + md_super_write(mddev, rdev, sboff + ps, (int)min(size, bitmap_limit), page); return 0; } diff --git a/drivers/md/md.c b/drivers/md/md.c index f1c7d4f281c5..69ea54aedd99 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -69,6 +69,16 @@ #include "md-bitmap.h" #include "md-cluster.h" +static const char *action_name[NR_SYNC_ACTIONS] = { + [ACTION_RESYNC] = "resync", + [ACTION_RECOVER] = "recover", + [ACTION_CHECK] = "check", + [ACTION_REPAIR] = "repair", + [ACTION_RESHAPE] = "reshape", + [ACTION_FROZEN] = "frozen", + [ACTION_IDLE] = "idle", +}; + /* pers_list is a list of registered personalities protected by pers_lock. */ static LIST_HEAD(pers_list); static DEFINE_SPINLOCK(pers_lock); @@ -479,7 +489,6 @@ int mddev_suspend(struct mddev *mddev, bool interruptible) */ WRITE_ONCE(mddev->suspended, mddev->suspended + 1); - del_timer_sync(&mddev->safemode_timer); /* restrict memory reclaim I/O during raid array is suspend */ mddev->noio_flag = memalloc_noio_save(); @@ -550,13 +559,9 @@ static void md_end_flush(struct bio *bio) rdev_dec_pending(rdev, mddev); - if (atomic_dec_and_test(&mddev->flush_pending)) { - /* The pair is percpu_ref_get() from md_flush_request() */ - percpu_ref_put(&mddev->active_io); - + if (atomic_dec_and_test(&mddev->flush_pending)) /* The pre-request flush has finished */ queue_work(md_wq, &mddev->flush_work); - } } static void md_submit_flush_data(struct work_struct *ws); @@ -587,12 +592,8 @@ static void submit_flushes(struct work_struct *ws) rcu_read_lock(); } rcu_read_unlock(); - if (atomic_dec_and_test(&mddev->flush_pending)) { - /* The pair is percpu_ref_get() from md_flush_request() */ - percpu_ref_put(&mddev->active_io); - + if (atomic_dec_and_test(&mddev->flush_pending)) queue_work(md_wq, &mddev->flush_work); - } } static void md_submit_flush_data(struct work_struct *ws) @@ -617,8 +618,20 @@ static void md_submit_flush_data(struct work_struct *ws) bio_endio(bio); } else { bio->bi_opf &= ~REQ_PREFLUSH; - md_handle_request(mddev, bio); + + /* + * make_requst() will never return error here, it only + * returns error in raid5_make_request() by dm-raid. + * Since dm always splits data and flush operation into + * two separate io, io size of flush submitted by dm + * always is 0, make_request() will not be called here. + */ + if (WARN_ON_ONCE(!mddev->pers->make_request(mddev, bio))) + bio_io_error(bio);; } + + /* The pair is percpu_ref_get() from md_flush_request() */ + percpu_ref_put(&mddev->active_io); } /* @@ -654,24 +667,22 @@ bool md_flush_request(struct mddev *mddev, struct bio *bio) WARN_ON(percpu_ref_is_zero(&mddev->active_io)); percpu_ref_get(&mddev->active_io); mddev->flush_bio = bio; - bio = NULL; - } - spin_unlock_irq(&mddev->lock); - - if (!bio) { + spin_unlock_irq(&mddev->lock); INIT_WORK(&mddev->flush_work, submit_flushes); queue_work(md_wq, &mddev->flush_work); - } else { - /* flush was performed for some other bio while we waited. */ - if (bio->bi_iter.bi_size == 0) - /* an empty barrier - all done */ - bio_endio(bio); - else { - bio->bi_opf &= ~REQ_PREFLUSH; - return false; - } + return true; } - return true; + + /* flush was performed for some other bio while we waited. */ + spin_unlock_irq(&mddev->lock); + if (bio->bi_iter.bi_size == 0) { + /* pure flush without data - all done */ + bio_endio(bio); + return true; + } + + bio->bi_opf &= ~REQ_PREFLUSH; + return false; } EXPORT_SYMBOL(md_flush_request); @@ -742,7 +753,6 @@ int mddev_init(struct mddev *mddev) mutex_init(&mddev->open_mutex); mutex_init(&mddev->reconfig_mutex); - mutex_init(&mddev->sync_mutex); mutex_init(&mddev->suspend_mutex); mutex_init(&mddev->bitmap_info.mutex); INIT_LIST_HEAD(&mddev->disks); @@ -758,7 +768,7 @@ int mddev_init(struct mddev *mddev) init_waitqueue_head(&mddev->recovery_wait); mddev->reshape_position = MaxSector; mddev->reshape_backwards = 0; - mddev->last_sync_action = "none"; + mddev->last_sync_action = ACTION_IDLE; mddev->resync_min = 0; mddev->resync_max = MaxSector; mddev->level = LEVEL_NONE; @@ -4815,30 +4825,81 @@ out_unlock: static struct md_sysfs_entry md_metadata = __ATTR_PREALLOC(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store); -static ssize_t -action_show(struct mddev *mddev, char *page) +enum sync_action md_sync_action(struct mddev *mddev) { - char *type = "idle"; unsigned long recovery = mddev->recovery; + + /* + * frozen has the highest priority, means running sync_thread will be + * stopped immediately, and no new sync_thread can start. + */ if (test_bit(MD_RECOVERY_FROZEN, &recovery)) - type = "frozen"; - else if (test_bit(MD_RECOVERY_RUNNING, &recovery) || - (md_is_rdwr(mddev) && test_bit(MD_RECOVERY_NEEDED, &recovery))) { - if (test_bit(MD_RECOVERY_RESHAPE, &recovery)) - type = "reshape"; - else if (test_bit(MD_RECOVERY_SYNC, &recovery)) { - if (!test_bit(MD_RECOVERY_REQUESTED, &recovery)) - type = "resync"; - else if (test_bit(MD_RECOVERY_CHECK, &recovery)) - type = "check"; - else - type = "repair"; - } else if (test_bit(MD_RECOVERY_RECOVER, &recovery)) - type = "recover"; - else if (mddev->reshape_position != MaxSector) - type = "reshape"; + return ACTION_FROZEN; + + /* + * read-only array can't register sync_thread, and it can only + * add/remove spares. + */ + if (!md_is_rdwr(mddev)) + return ACTION_IDLE; + + /* + * idle means no sync_thread is running, and no new sync_thread is + * requested. + */ + if (!test_bit(MD_RECOVERY_RUNNING, &recovery) && + !test_bit(MD_RECOVERY_NEEDED, &recovery)) + return ACTION_IDLE; + + if (test_bit(MD_RECOVERY_RESHAPE, &recovery) || + mddev->reshape_position != MaxSector) + return ACTION_RESHAPE; + + if (test_bit(MD_RECOVERY_RECOVER, &recovery)) + return ACTION_RECOVER; + + if (test_bit(MD_RECOVERY_SYNC, &recovery)) { + /* + * MD_RECOVERY_CHECK must be paired with + * MD_RECOVERY_REQUESTED. + */ + if (test_bit(MD_RECOVERY_CHECK, &recovery)) + return ACTION_CHECK; + if (test_bit(MD_RECOVERY_REQUESTED, &recovery)) + return ACTION_REPAIR; + return ACTION_RESYNC; } - return sprintf(page, "%s\n", type); + + /* + * MD_RECOVERY_NEEDED or MD_RECOVERY_RUNNING is set, however, no + * sync_action is specified. + */ + return ACTION_IDLE; +} + +enum sync_action md_sync_action_by_name(const char *page) +{ + enum sync_action action; + + for (action = 0; action < NR_SYNC_ACTIONS; ++action) { + if (cmd_match(page, action_name[action])) + return action; + } + + return NR_SYNC_ACTIONS; +} + +const char *md_sync_action_name(enum sync_action action) +{ + return action_name[action]; +} + +static ssize_t +action_show(struct mddev *mddev, char *page) +{ + enum sync_action action = md_sync_action(mddev); + + return sprintf(page, "%s\n", md_sync_action_name(action)); } /** @@ -4847,15 +4908,10 @@ action_show(struct mddev *mddev, char *page) * @locked: if set, reconfig_mutex will still be held after this function * return; if not set, reconfig_mutex will be released after this * function return. - * @check_seq: if set, only wait for curent running sync_thread to stop, noted - * that new sync_thread can still start. */ -static void stop_sync_thread(struct mddev *mddev, bool locked, bool check_seq) +static void stop_sync_thread(struct mddev *mddev, bool locked) { - int sync_seq; - - if (check_seq) - sync_seq = atomic_read(&mddev->sync_seq); + int sync_seq = atomic_read(&mddev->sync_seq); if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { if (!locked) @@ -4876,7 +4932,8 @@ static void stop_sync_thread(struct mddev *mddev, bool locked, bool check_seq) wait_event(resync_wait, !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) || - (check_seq && sync_seq != atomic_read(&mddev->sync_seq))); + (!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery) && + sync_seq != atomic_read(&mddev->sync_seq))); if (locked) mddev_lock_nointr(mddev); @@ -4887,7 +4944,7 @@ void md_idle_sync_thread(struct mddev *mddev) lockdep_assert_held(&mddev->reconfig_mutex); clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - stop_sync_thread(mddev, true, true); + stop_sync_thread(mddev, true); } EXPORT_SYMBOL_GPL(md_idle_sync_thread); @@ -4896,7 +4953,7 @@ void md_frozen_sync_thread(struct mddev *mddev) lockdep_assert_held(&mddev->reconfig_mutex); set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - stop_sync_thread(mddev, true, false); + stop_sync_thread(mddev, true); } EXPORT_SYMBOL_GPL(md_frozen_sync_thread); @@ -4911,100 +4968,127 @@ void md_unfrozen_sync_thread(struct mddev *mddev) } EXPORT_SYMBOL_GPL(md_unfrozen_sync_thread); -static void idle_sync_thread(struct mddev *mddev) +static int mddev_start_reshape(struct mddev *mddev) { - mutex_lock(&mddev->sync_mutex); - clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - - if (mddev_lock(mddev)) { - mutex_unlock(&mddev->sync_mutex); - return; - } - - stop_sync_thread(mddev, false, true); - mutex_unlock(&mddev->sync_mutex); -} + int ret; -static void frozen_sync_thread(struct mddev *mddev) -{ - mutex_lock(&mddev->sync_mutex); - set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + if (mddev->pers->start_reshape == NULL) + return -EINVAL; - if (mddev_lock(mddev)) { - mutex_unlock(&mddev->sync_mutex); - return; + if (mddev->reshape_position == MaxSector || + mddev->pers->check_reshape == NULL || + mddev->pers->check_reshape(mddev)) { + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + ret = mddev->pers->start_reshape(mddev); + if (ret) + return ret; + } else { + /* + * If reshape is still in progress, and md_check_recovery() can + * continue to reshape, don't restart reshape because data can + * be corrupted for raid456. + */ + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); } - stop_sync_thread(mddev, false, false); - mutex_unlock(&mddev->sync_mutex); + sysfs_notify_dirent_safe(mddev->sysfs_degraded); + return 0; } static ssize_t action_store(struct mddev *mddev, const char *page, size_t len) { + int ret; + enum sync_action action; + if (!mddev->pers || !mddev->pers->sync_request) return -EINVAL; +retry: + if (work_busy(&mddev->sync_work)) + flush_work(&mddev->sync_work); - if (cmd_match(page, "idle")) - idle_sync_thread(mddev); - else if (cmd_match(page, "frozen")) - frozen_sync_thread(mddev); - else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) - return -EBUSY; - else if (cmd_match(page, "resync")) - clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - else if (cmd_match(page, "recover")) { - clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - set_bit(MD_RECOVERY_RECOVER, &mddev->recovery); - } else if (cmd_match(page, "reshape")) { - int err; - if (mddev->pers->start_reshape == NULL) - return -EINVAL; - err = mddev_lock(mddev); - if (!err) { - if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { - err = -EBUSY; - } else if (mddev->reshape_position == MaxSector || - mddev->pers->check_reshape == NULL || - mddev->pers->check_reshape(mddev)) { - clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - err = mddev->pers->start_reshape(mddev); - } else { - /* - * If reshape is still in progress, and - * md_check_recovery() can continue to reshape, - * don't restart reshape because data can be - * corrupted for raid456. - */ - clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - } - mddev_unlock(mddev); + ret = mddev_lock(mddev); + if (ret) + return ret; + + if (work_busy(&mddev->sync_work)) { + mddev_unlock(mddev); + goto retry; + } + + action = md_sync_action_by_name(page); + + /* TODO: mdadm rely on "idle" to start sync_thread. */ + if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { + switch (action) { + case ACTION_FROZEN: + md_frozen_sync_thread(mddev); + ret = len; + goto out; + case ACTION_IDLE: + md_idle_sync_thread(mddev); + break; + case ACTION_RESHAPE: + case ACTION_RECOVER: + case ACTION_CHECK: + case ACTION_REPAIR: + case ACTION_RESYNC: + ret = -EBUSY; + goto out; + default: + ret = -EINVAL; + goto out; } - if (err) - return err; - sysfs_notify_dirent_safe(mddev->sysfs_degraded); } else { - if (cmd_match(page, "check")) + switch (action) { + case ACTION_FROZEN: + set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + ret = len; + goto out; + case ACTION_RESHAPE: + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + ret = mddev_start_reshape(mddev); + if (ret) + goto out; + break; + case ACTION_RECOVER: + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + set_bit(MD_RECOVERY_RECOVER, &mddev->recovery); + break; + case ACTION_CHECK: set_bit(MD_RECOVERY_CHECK, &mddev->recovery); - else if (!cmd_match(page, "repair")) - return -EINVAL; - clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery); - set_bit(MD_RECOVERY_SYNC, &mddev->recovery); + fallthrough; + case ACTION_REPAIR: + set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery); + set_bit(MD_RECOVERY_SYNC, &mddev->recovery); + fallthrough; + case ACTION_RESYNC: + case ACTION_IDLE: + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + break; + default: + ret = -EINVAL; + goto out; + } } + if (mddev->ro == MD_AUTO_READ) { /* A write to sync_action is enough to justify * canceling read-auto mode */ - flush_work(&mddev->sync_work); mddev->ro = MD_RDWR; md_wakeup_thread(mddev->sync_thread); } + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); md_wakeup_thread(mddev->thread); sysfs_notify_dirent_safe(mddev->sysfs_action); - return len; + ret = len; + +out: + mddev_unlock(mddev); + return ret; } static struct md_sysfs_entry md_scan_mode = @@ -5013,7 +5097,8 @@ __ATTR_PREALLOC(sync_action, S_IRUGO|S_IWUSR, action_show, action_store); static ssize_t last_sync_action_show(struct mddev *mddev, char *page) { - return sprintf(page, "%s\n", mddev->last_sync_action); + return sprintf(page, "%s\n", + md_sync_action_name(mddev->last_sync_action)); } static struct md_sysfs_entry md_last_scan_mode = __ATTR_RO(last_sync_action); @@ -6380,7 +6465,7 @@ void md_stop_writes(struct mddev *mddev) { mddev_lock_nointr(mddev); set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); - stop_sync_thread(mddev, true, false); + stop_sync_thread(mddev, true); __md_stop_writes(mddev); mddev_unlock(mddev); } @@ -6448,7 +6533,7 @@ static int md_set_readonly(struct mddev *mddev) set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); } - stop_sync_thread(mddev, false, false); + stop_sync_thread(mddev, false); wait_event(mddev->sb_wait, !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)); mddev_lock_nointr(mddev); @@ -6494,7 +6579,7 @@ static int do_md_stop(struct mddev *mddev, int mode) set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); } - stop_sync_thread(mddev, true, false); + stop_sync_thread(mddev, true); if (mddev->sysfs_active || test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { @@ -8575,12 +8660,12 @@ EXPORT_SYMBOL(md_done_sync); * A return value of 'false' means that the write wasn't recorded * and cannot proceed as the array is being suspend. */ -bool md_write_start(struct mddev *mddev, struct bio *bi) +void md_write_start(struct mddev *mddev, struct bio *bi) { int did_change = 0; if (bio_data_dir(bi) != WRITE) - return true; + return; BUG_ON(mddev->ro == MD_RDONLY); if (mddev->ro == MD_AUTO_READ) { @@ -8613,15 +8698,9 @@ bool md_write_start(struct mddev *mddev, struct bio *bi) if (did_change) sysfs_notify_dirent_safe(mddev->sysfs_state); if (!mddev->has_superblocks) - return true; + return; wait_event(mddev->sb_wait, - !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) || - is_md_suspended(mddev)); - if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) { - percpu_ref_put(&mddev->writes_pending); - return false; - } - return true; + !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)); } EXPORT_SYMBOL(md_write_start); @@ -8769,6 +8848,77 @@ void md_allow_write(struct mddev *mddev) } EXPORT_SYMBOL_GPL(md_allow_write); +static sector_t md_sync_max_sectors(struct mddev *mddev, + enum sync_action action) +{ + switch (action) { + case ACTION_RESYNC: + case ACTION_CHECK: + case ACTION_REPAIR: + atomic64_set(&mddev->resync_mismatches, 0); + fallthrough; + case ACTION_RESHAPE: + return mddev->resync_max_sectors; + case ACTION_RECOVER: + return mddev->dev_sectors; + default: + return 0; + } +} + +static sector_t md_sync_position(struct mddev *mddev, enum sync_action action) +{ + sector_t start = 0; + struct md_rdev *rdev; + + switch (action) { + case ACTION_CHECK: + case ACTION_REPAIR: + return mddev->resync_min; + case ACTION_RESYNC: + if (!mddev->bitmap) + return mddev->recovery_cp; + return 0; + case ACTION_RESHAPE: + /* + * If the original node aborts reshaping then we continue the + * reshaping, so set again to avoid restart reshape from the + * first beginning + */ + if (mddev_is_clustered(mddev) && + mddev->reshape_position != MaxSector) + return mddev->reshape_position; + return 0; + case ACTION_RECOVER: + start = MaxSector; + rcu_read_lock(); + rdev_for_each_rcu(rdev, mddev) + if (rdev->raid_disk >= 0 && + !test_bit(Journal, &rdev->flags) && + !test_bit(Faulty, &rdev->flags) && + !test_bit(In_sync, &rdev->flags) && + rdev->recovery_offset < start) + start = rdev->recovery_offset; + rcu_read_unlock(); + + /* If there is a bitmap, we need to make sure all + * writes that started before we added a spare + * complete before we start doing a recovery. + * Otherwise the write might complete and (via + * bitmap_endwrite) set a bit in the bitmap after the + * recovery has checked that bit and skipped that + * region. + */ + if (mddev->bitmap) { + mddev->pers->quiesce(mddev, 1); + mddev->pers->quiesce(mddev, 0); + } + return start; + default: + return MaxSector; + } +} + #define SYNC_MARKS 10 #define SYNC_MARK_STEP (3*HZ) #define UPDATE_FREQUENCY (5*60*HZ) @@ -8785,7 +8935,8 @@ void md_do_sync(struct md_thread *thread) sector_t last_check; int skipped = 0; struct md_rdev *rdev; - char *desc, *action = NULL; + enum sync_action action; + const char *desc; struct blk_plug plug; int ret; @@ -8816,21 +8967,9 @@ void md_do_sync(struct md_thread *thread) goto skip; } - if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { - if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) { - desc = "data-check"; - action = "check"; - } else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { - desc = "requested-resync"; - action = "repair"; - } else - desc = "resync"; - } else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) - desc = "reshape"; - else - desc = "recovery"; - - mddev->last_sync_action = action ?: desc; + action = md_sync_action(mddev); + desc = md_sync_action_name(action); + mddev->last_sync_action = action; /* * Before starting a resync we must have set curr_resync to @@ -8898,56 +9037,8 @@ void md_do_sync(struct md_thread *thread) spin_unlock(&all_mddevs_lock); } while (mddev->curr_resync < MD_RESYNC_DELAYED); - j = 0; - if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { - /* resync follows the size requested by the personality, - * which defaults to physical size, but can be virtual size - */ - max_sectors = mddev->resync_max_sectors; - atomic64_set(&mddev->resync_mismatches, 0); - /* we don't use the checkpoint if there's a bitmap */ - if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) - j = mddev->resync_min; - else if (!mddev->bitmap) - j = mddev->recovery_cp; - - } else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) { - max_sectors = mddev->resync_max_sectors; - /* - * If the original node aborts reshaping then we continue the - * reshaping, so set j again to avoid restart reshape from the - * first beginning - */ - if (mddev_is_clustered(mddev) && - mddev->reshape_position != MaxSector) - j = mddev->reshape_position; - } else { - /* recovery follows the physical size of devices */ - max_sectors = mddev->dev_sectors; - j = MaxSector; - rcu_read_lock(); - rdev_for_each_rcu(rdev, mddev) - if (rdev->raid_disk >= 0 && - !test_bit(Journal, &rdev->flags) && - !test_bit(Faulty, &rdev->flags) && - !test_bit(In_sync, &rdev->flags) && - rdev->recovery_offset < j) - j = rdev->recovery_offset; - rcu_read_unlock(); - - /* If there is a bitmap, we need to make sure all - * writes that started before we added a spare - * complete before we start doing a recovery. - * Otherwise the write might complete and (via - * bitmap_endwrite) set a bit in the bitmap after the - * recovery has checked that bit and skipped that - * region. - */ - if (mddev->bitmap) { - mddev->pers->quiesce(mddev, 1); - mddev->pers->quiesce(mddev, 0); - } - } + max_sectors = md_sync_max_sectors(mddev, action); + j = md_sync_position(mddev, action); pr_info("md: %s of RAID array %s\n", desc, mdname(mddev)); pr_debug("md: minimum _guaranteed_ speed: %d KB/sec/disk.\n", speed_min(mddev)); @@ -9029,7 +9120,8 @@ void md_do_sync(struct md_thread *thread) if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) break; - sectors = mddev->pers->sync_request(mddev, j, &skipped); + sectors = mddev->pers->sync_request(mddev, j, max_sectors, + &skipped); if (sectors == 0) { set_bit(MD_RECOVERY_INTR, &mddev->recovery); break; @@ -9119,7 +9211,7 @@ void md_do_sync(struct md_thread *thread) mddev->curr_resync_completed = mddev->curr_resync; sysfs_notify_dirent_safe(mddev->sysfs_completed); } - mddev->pers->sync_request(mddev, max_sectors, &skipped); + mddev->pers->sync_request(mddev, max_sectors, max_sectors, &skipped); if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) && mddev->curr_resync > MD_RESYNC_ACTIVE) { diff --git a/drivers/md/md.h b/drivers/md/md.h index 6733b0b0abf9..c4d7ebf9587d 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -34,6 +34,61 @@ */ #define MD_FAILFAST (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT) +/* Status of sync thread. */ +enum sync_action { + /* + * Represent by MD_RECOVERY_SYNC, start when: + * 1) after assemble, sync data from first rdev to other copies, this + * must be done first before other sync actions and will only execute + * once; + * 2) resize the array(notice that this is not reshape), sync data for + * the new range; + */ + ACTION_RESYNC, + /* + * Represent by MD_RECOVERY_RECOVER, start when: + * 1) for new replacement, sync data based on the replace rdev or + * available copies from other rdev; + * 2) for new member disk while the array is degraded, sync data from + * other rdev; + * 3) reassemble after power failure or re-add a hot removed rdev, sync + * data from first rdev to other copies based on bitmap; + */ + ACTION_RECOVER, + /* + * Represent by MD_RECOVERY_SYNC | MD_RECOVERY_REQUESTED | + * MD_RECOVERY_CHECK, start when user echo "check" to sysfs api + * sync_action, used to check if data copies from differenct rdev are + * the same. The number of mismatch sectors will be exported to user + * by sysfs api mismatch_cnt; + */ + ACTION_CHECK, + /* + * Represent by MD_RECOVERY_SYNC | MD_RECOVERY_REQUESTED, start when + * user echo "repair" to sysfs api sync_action, usually paired with + * ACTION_CHECK, used to force syncing data once user found that there + * are inconsistent data, + */ + ACTION_REPAIR, + /* + * Represent by MD_RECOVERY_RESHAPE, start when new member disk is added + * to the conf, notice that this is different from spares or + * replacement; + */ + ACTION_RESHAPE, + /* + * Represent by MD_RECOVERY_FROZEN, can be set by sysfs api sync_action + * or internal usage like setting the array read-only, will forbid above + * actions. + */ + ACTION_FROZEN, + /* + * All above actions don't match. + */ + ACTION_IDLE, + NR_SYNC_ACTIONS, +}; + /* * The struct embedded in rdev is used to serialize IO. */ @@ -371,13 +426,12 @@ struct mddev { struct md_thread __rcu *thread; /* management thread */ struct md_thread __rcu *sync_thread; /* doing resync or reconstruct */ - /* 'last_sync_action' is initialized to "none". It is set when a - * sync operation (i.e "data-check", "requested-resync", "resync", - * "recovery", or "reshape") is started. It holds this value even + /* + * Set when a sync operation is started. It holds this value even * when the sync thread is "frozen" (interrupted) or "idle" (stopped - * or finished). It is overwritten when a new sync operation is begun. + * or finished). It is overwritten when a new sync operation is begun. */ - char *last_sync_action; + enum sync_action last_sync_action; sector_t curr_resync; /* last block scheduled */ /* As resync requests can complete out of order, we cannot easily track * how much resync has been completed. So we occasionally pause until @@ -540,8 +594,6 @@ struct mddev { */ struct list_head deleting; - /* Used to synchronize idle and frozen for action_store() */ - struct mutex sync_mutex; /* The sequence number for sync thread */ atomic_t sync_seq; @@ -551,22 +603,46 @@ struct mddev { }; enum recovery_flags { + /* flags for sync thread running status */ + + /* + * set when one of sync action is set and new sync thread need to be + * registered, or just add/remove spares from conf. + */ + MD_RECOVERY_NEEDED, + /* sync thread is running, or about to be started */ + MD_RECOVERY_RUNNING, + /* sync thread needs to be aborted for some reason */ + MD_RECOVERY_INTR, + /* sync thread is done and is waiting to be unregistered */ + MD_RECOVERY_DONE, + /* running sync thread must abort immediately, and not restart */ + MD_RECOVERY_FROZEN, + /* waiting for pers->start() to finish */ + MD_RECOVERY_WAIT, + /* interrupted because io-error */ + MD_RECOVERY_ERROR, + + /* flags determines sync action, see details in enum sync_action */ + + /* if just this flag is set, action is resync. */ + MD_RECOVERY_SYNC, + /* + * paired with MD_RECOVERY_SYNC, if MD_RECOVERY_CHECK is not set, + * action is repair, means user requested resync. + */ + MD_RECOVERY_REQUESTED, /* - * If neither SYNC or RESHAPE are set, then it is a recovery. + * paired with MD_RECOVERY_SYNC and MD_RECOVERY_REQUESTED, action is + * check. */ - MD_RECOVERY_RUNNING, /* a thread is running, or about to be started */ - MD_RECOVERY_SYNC, /* actually doing a resync, not a recovery */ - MD_RECOVERY_RECOVER, /* doing recovery, or need to try it. */ - MD_RECOVERY_INTR, /* resync needs to be aborted for some reason */ - MD_RECOVERY_DONE, /* thread is done and is waiting to be reaped */ - MD_RECOVERY_NEEDED, /* we might need to start a resync/recover */ - MD_RECOVERY_REQUESTED, /* user-space has requested a sync (used with SYNC) */ - MD_RECOVERY_CHECK, /* user-space request for check-only, no repair */ - MD_RECOVERY_RESHAPE, /* A reshape is happening */ - MD_RECOVERY_FROZEN, /* User request to abort, and not restart, any action */ - MD_RECOVERY_ERROR, /* sync-action interrupted because io-error */ - MD_RECOVERY_WAIT, /* waiting for pers->start() to finish */ - MD_RESYNCING_REMOTE, /* remote node is running resync thread */ + MD_RECOVERY_CHECK, + /* recovery, or need to try it */ + MD_RECOVERY_RECOVER, + /* reshape */ + MD_RECOVERY_RESHAPE, + /* remote node is running resync thread */ + MD_RESYNCING_REMOTE, }; enum md_ro_state { @@ -653,7 +729,8 @@ struct md_personality int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev); int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev); int (*spare_active) (struct mddev *mddev); - sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped); + sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, + sector_t max_sector, int *skipped); int (*resize) (struct mddev *mddev, sector_t sectors); sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks); int (*check_reshape) (struct mddev *mddev); @@ -785,7 +862,10 @@ extern void md_unregister_thread(struct mddev *mddev, struct md_thread __rcu **t extern void md_wakeup_thread(struct md_thread __rcu *thread); extern void md_check_recovery(struct mddev *mddev); extern void md_reap_sync_thread(struct mddev *mddev); -extern bool md_write_start(struct mddev *mddev, struct bio *bi); +extern enum sync_action md_sync_action(struct mddev *mddev); +extern enum sync_action md_sync_action_by_name(const char *page); +extern const char *md_sync_action_name(enum sync_action action); +extern void md_write_start(struct mddev *mddev, struct bio *bi); extern void md_write_inc(struct mddev *mddev, struct bio *bi); extern void md_write_end(struct mddev *mddev); extern void md_done_sync(struct mddev *mddev, int blocks, int ok); diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 779cad62f6f8..1a0eba65b8a9 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1687,8 +1687,7 @@ static bool raid1_make_request(struct mddev *mddev, struct bio *bio) if (bio_data_dir(bio) == READ) raid1_read_request(mddev, bio, sectors, NULL); else { - if (!md_write_start(mddev,bio)) - return false; + md_write_start(mddev,bio); raid1_write_request(mddev, bio, sectors); } return true; @@ -2754,12 +2753,12 @@ static struct r1bio *raid1_alloc_init_r1buf(struct r1conf *conf) */ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr, - int *skipped) + sector_t max_sector, int *skipped) { struct r1conf *conf = mddev->private; struct r1bio *r1_bio; struct bio *bio; - sector_t max_sector, nr_sectors; + sector_t nr_sectors; int disk = -1; int i; int wonly = -1; @@ -2775,7 +2774,6 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr, if (init_resync(conf)) return 0; - max_sector = mddev->dev_sectors; if (sector_nr >= max_sector) { /* If we aborted, we need to abort the * sync on the 'current' bitmap chunk (there will diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 5f6885b53b69..3334aa803c83 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1836,8 +1836,7 @@ static bool raid10_make_request(struct mddev *mddev, struct bio *bio) && md_flush_request(mddev, bio)) return true; - if (!md_write_start(mddev, bio)) - return false; + md_write_start(mddev, bio); if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) if (!raid10_handle_discard(mddev, bio)) @@ -3137,12 +3136,12 @@ static void raid10_set_cluster_sync_high(struct r10conf *conf) */ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr, - int *skipped) + sector_t max_sector, int *skipped) { struct r10conf *conf = mddev->private; struct r10bio *r10_bio; struct bio *biolist = NULL, *bio; - sector_t max_sector, nr_sectors; + sector_t nr_sectors; int i; int max_sync; sector_t sync_blocks; @@ -3172,10 +3171,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr, return 0; skipped: - max_sector = mddev->dev_sectors; - if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) || - test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) - max_sector = mddev->resync_max_sectors; if (sector_nr >= max_sector) { conf->cluster_sync_low = 0; conf->cluster_sync_high = 0; diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 72f91eaa3201..0192a6323f09 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6078,8 +6078,7 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) ctx.do_flush = bi->bi_opf & REQ_PREFLUSH; } - if (!md_write_start(mddev, bi)) - return false; + md_write_start(mddev, bi); /* * If array is degraded, better not do chunk aligned read because * later we might have to read it again in order to reconstruct @@ -6255,7 +6254,9 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk safepos = conf->reshape_safe; sector_div(safepos, data_disks); if (mddev->reshape_backwards) { - BUG_ON(writepos < reshape_sectors); + if (WARN_ON(writepos < reshape_sectors)) + return MaxSector; + writepos -= reshape_sectors; readpos += reshape_sectors; safepos += reshape_sectors; @@ -6273,14 +6274,18 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk * to set 'stripe_addr' which is where we will write to. */ if (mddev->reshape_backwards) { - BUG_ON(conf->reshape_progress == 0); + if (WARN_ON(conf->reshape_progress == 0)) + return MaxSector; + stripe_addr = writepos; - BUG_ON((mddev->dev_sectors & - ~((sector_t)reshape_sectors - 1)) - - reshape_sectors - stripe_addr - != sector_nr); + if (WARN_ON((mddev->dev_sectors & + ~((sector_t)reshape_sectors - 1)) - + reshape_sectors - stripe_addr != sector_nr)) + return MaxSector; } else { - BUG_ON(writepos != sector_nr + reshape_sectors); + if (WARN_ON(writepos != sector_nr + reshape_sectors)) + return MaxSector; + stripe_addr = sector_nr; } @@ -6458,11 +6463,10 @@ ret: } static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr, - int *skipped) + sector_t max_sector, int *skipped) { struct r5conf *conf = mddev->private; struct stripe_head *sh; - sector_t max_sector = mddev->dev_sectors; sector_t sync_blocks; int still_degraded = 0; int i; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1fa2b148c206..0e8253c1507a 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -931,7 +931,6 @@ static inline unsigned int blk_chunk_sectors_left(sector_t offset, */ static inline struct queue_limits queue_limits_start_update(struct request_queue *q) - __acquires(q->limits_lock) { mutex_lock(&q->limits_lock); return q->limits; diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index ddb5644d4fd9..84f601d7068e 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -7,6 +7,8 @@ */ #include <kunit/test.h> +#include <linux/blk_types.h> +#include <linux/blk-mq.h> #include <linux/errname.h> #include <linux/ethtool.h> #include <linux/jiffies.h> @@ -20,6 +22,7 @@ /* `bindgen` gets confused at certain things. */ const size_t RUST_CONST_HELPER_ARCH_SLAB_MINALIGN = ARCH_SLAB_MINALIGN; +const size_t RUST_CONST_HELPER_PAGE_SIZE = PAGE_SIZE; const gfp_t RUST_CONST_HELPER_GFP_ATOMIC = GFP_ATOMIC; const gfp_t RUST_CONST_HELPER_GFP_KERNEL = GFP_KERNEL; const gfp_t RUST_CONST_HELPER_GFP_KERNEL_ACCOUNT = GFP_KERNEL_ACCOUNT; diff --git a/rust/helpers.c b/rust/helpers.c index 2c37a0f5d7a8..3df5217fb2ff 100644 --- a/rust/helpers.c +++ b/rust/helpers.c @@ -186,3 +186,19 @@ static_assert( __alignof__(size_t) == __alignof__(uintptr_t), "Rust code expects C `size_t` to match Rust `usize`" ); + +// This will soon be moved to a separate file, so no need to merge with above. +#include <linux/blk-mq.h> +#include <linux/blkdev.h> + +void *rust_helper_blk_mq_rq_to_pdu(struct request *rq) +{ + return blk_mq_rq_to_pdu(rq); +} +EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_to_pdu); + +struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu) +{ + return blk_mq_rq_from_pdu(pdu); +} +EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_from_pdu); diff --git a/rust/kernel/block.rs b/rust/kernel/block.rs new file mode 100644 index 000000000000..150f710efe5b --- /dev/null +++ b/rust/kernel/block.rs @@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Types for working with the block layer. + +pub mod mq; diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs new file mode 100644 index 000000000000..fb0f393c1cea --- /dev/null +++ b/rust/kernel/block/mq.rs @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! This module provides types for implementing block drivers that interface the +//! blk-mq subsystem. +//! +//! To implement a block device driver, a Rust module must do the following: +//! +//! - Implement [`Operations`] for a type `T`. +//! - Create a [`TagSet<T>`]. +//! - Create a [`GenDisk<T>`], via the [`GenDiskBuilder`]. +//! - Add the disk to the system by calling [`GenDiskBuilder::build`] passing in +//! the `TagSet` reference. +//! +//! The types available in this module that have direct C counterparts are: +//! +//! - The [`TagSet`] type that abstracts the C type `struct tag_set`. +//! - The [`GenDisk`] type that abstracts the C type `struct gendisk`. +//! - The [`Request`] type that abstracts the C type `struct request`. +//! +//! The kernel will interface with the block device driver by calling the method +//! implementations of the `Operations` trait. +//! +//! IO requests are passed to the driver as [`kernel::types::ARef<Request>`] +//! instances. The `Request` type is a wrapper around the C `struct request`. +//! The driver must mark end of processing by calling one of the +//! `Request::end`, methods. Failure to do so can lead to deadlock or timeout +//! errors. Please note that the C function `blk_mq_start_request` is implicitly +//! called when the request is queued with the driver. +//! +//! The `TagSet` is responsible for creating and maintaining a mapping between +//! `Request`s and integer ids as well as carrying a pointer to the vtable +//! generated by `Operations`. This mapping is useful for associating +//! completions from hardware with the correct `Request` instance. The `TagSet` +//! determines the maximum queue depth by setting the number of `Request` +//! instances available to the driver, and it determines the number of queues to +//! instantiate for the driver. If possible, a driver should allocate one queue +//! per core, to keep queue data local to a core. +//! +//! One `TagSet` instance can be shared between multiple `GenDisk` instances. +//! This can be useful when implementing drivers where one piece of hardware +//! with one set of IO resources are represented to the user as multiple disks. +//! +//! One significant difference between block device drivers implemented with +//! these Rust abstractions and drivers implemented in C, is that the Rust +//! drivers have to own a reference count on the `Request` type when the IO is +//! in flight. This is to ensure that the C `struct request` instances backing +//! the Rust `Request` instances are live while the Rust driver holds a +//! reference to the `Request`. In addition, the conversion of an integer tag to +//! a `Request` via the `TagSet` would not be sound without this bookkeeping. +//! +//! [`GenDisk`]: gen_disk::GenDisk +//! [`GenDisk<T>`]: gen_disk::GenDisk +//! [`GenDiskBuilder`]: gen_disk::GenDiskBuilder +//! [`GenDiskBuilder::build`]: gen_disk::GenDiskBuilder::build +//! +//! # Example +//! +//! ```rust +//! use kernel::{ +//! alloc::flags, +//! block::mq::*, +//! new_mutex, +//! prelude::*, +//! sync::{Arc, Mutex}, +//! types::{ARef, ForeignOwnable}, +//! }; +//! +//! struct MyBlkDevice; +//! +//! #[vtable] +//! impl Operations for MyBlkDevice { +//! +//! fn queue_rq(rq: ARef<Request<Self>>, _is_last: bool) -> Result { +//! Request::end_ok(rq); +//! Ok(()) +//! } +//! +//! fn commit_rqs() {} +//! } +//! +//! let tagset: Arc<TagSet<MyBlkDevice>> = +//! Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?; +//! let mut disk = gen_disk::GenDiskBuilder::new() +//! .capacity_sectors(4096) +//! .build(format_args!("myblk"), tagset)?; +//! +//! # Ok::<(), kernel::error::Error>(()) +//! ``` + +pub mod gen_disk; +mod operations; +mod raw_writer; +mod request; +mod tag_set; + +pub use operations::Operations; +pub use request::Request; +pub use tag_set::TagSet; diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs new file mode 100644 index 000000000000..f548a6199847 --- /dev/null +++ b/rust/kernel/block/mq/gen_disk.rs @@ -0,0 +1,198 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Generic disk abstraction. +//! +//! C header: [`include/linux/blkdev.h`](srctree/include/linux/blkdev.h) +//! C header: [`include/linux/blk_mq.h`](srctree/include/linux/blk_mq.h) + +use crate::block::mq::{raw_writer::RawWriter, Operations, TagSet}; +use crate::error; +use crate::{bindings, error::from_err_ptr, error::Result, sync::Arc}; +use core::fmt::{self, Write}; + +/// A builder for [`GenDisk`]. +/// +/// Use this struct to configure and add new [`GenDisk`] to the VFS. +pub struct GenDiskBuilder { + rotational: bool, + logical_block_size: u32, + physical_block_size: u32, + capacity_sectors: u64, +} + +impl Default for GenDiskBuilder { + fn default() -> Self { + Self { + rotational: false, + logical_block_size: bindings::PAGE_SIZE as u32, + physical_block_size: bindings::PAGE_SIZE as u32, + capacity_sectors: 0, + } + } +} + +impl GenDiskBuilder { + /// Create a new instance. + pub fn new() -> Self { + Self::default() + } + + /// Set the rotational media attribute for the device to be built. + pub fn rotational(mut self, rotational: bool) -> Self { + self.rotational = rotational; + self + } + + /// Validate block size by verifying that it is between 512 and `PAGE_SIZE`, + /// and that it is a power of two. + fn validate_block_size(size: u32) -> Result<()> { + if !(512..=bindings::PAGE_SIZE as u32).contains(&size) || !size.is_power_of_two() { + Err(error::code::EINVAL) + } else { + Ok(()) + } + } + + /// Set the logical block size of the device to be built. + /// + /// This method will check that block size is a power of two and between 512 + /// and 4096. If not, an error is returned and the block size is not set. + /// + /// This is the smallest unit the storage device can address. It is + /// typically 4096 bytes. + pub fn logical_block_size(mut self, block_size: u32) -> Result<Self> { + Self::validate_block_size(block_size)?; + self.logical_block_size = block_size; + Ok(self) + } + + /// Set the physical block size of the device to be built. + /// + /// This method will check that block size is a power of two and between 512 + /// and 4096. If not, an error is returned and the block size is not set. + /// + /// This is the smallest unit a physical storage device can write + /// atomically. It is usually the same as the logical block size but may be + /// bigger. One example is SATA drives with 4096 byte physical block size + /// that expose a 512 byte logical block size to the operating system. + pub fn physical_block_size(mut self, block_size: u32) -> Result<Self> { + Self::validate_block_size(block_size)?; + self.physical_block_size = block_size; + Ok(self) + } + + /// Set the capacity of the device to be built, in sectors (512 bytes). + pub fn capacity_sectors(mut self, capacity: u64) -> Self { + self.capacity_sectors = capacity; + self + } + + /// Build a new `GenDisk` and add it to the VFS. + pub fn build<T: Operations>( + self, + name: fmt::Arguments<'_>, + tagset: Arc<TagSet<T>>, + ) -> Result<GenDisk<T>> { + let lock_class_key = crate::sync::LockClassKey::new(); + + // SAFETY: `bindings::queue_limits` contain only fields that are valid when zeroed. + let mut lim: bindings::queue_limits = unsafe { core::mem::zeroed() }; + + lim.logical_block_size = self.logical_block_size; + lim.physical_block_size = self.physical_block_size; + if self.rotational { + lim.features = bindings::BLK_FEAT_ROTATIONAL; + } + + // SAFETY: `tagset.raw_tag_set()` points to a valid and initialized tag set + let gendisk = from_err_ptr(unsafe { + bindings::__blk_mq_alloc_disk( + tagset.raw_tag_set(), + &mut lim, + core::ptr::null_mut(), + lock_class_key.as_ptr(), + ) + })?; + + const TABLE: bindings::block_device_operations = bindings::block_device_operations { + submit_bio: None, + open: None, + release: None, + ioctl: None, + compat_ioctl: None, + check_events: None, + unlock_native_capacity: None, + getgeo: None, + set_read_only: None, + swap_slot_free_notify: None, + report_zones: None, + devnode: None, + alternative_gpt_sector: None, + get_unique_id: None, + // TODO: Set to THIS_MODULE. Waiting for const_refs_to_static feature to + // be merged (unstable in rustc 1.78 which is staged for linux 6.10) + // https://github.com/rust-lang/rust/issues/119618 + owner: core::ptr::null_mut(), + pr_ops: core::ptr::null_mut(), + free_disk: None, + poll_bio: None, + }; + + // SAFETY: `gendisk` is a valid pointer as we initialized it above + unsafe { (*gendisk).fops = &TABLE }; + + let mut raw_writer = RawWriter::from_array( + // SAFETY: `gendisk` points to a valid and initialized instance. We + // have exclusive access, since the disk is not added to the VFS + // yet. + unsafe { &mut (*gendisk).disk_name }, + )?; + raw_writer.write_fmt(name)?; + raw_writer.write_char('\0')?; + + // SAFETY: `gendisk` points to a valid and initialized instance of + // `struct gendisk`. `set_capacity` takes a lock to synchronize this + // operation, so we will not race. + unsafe { bindings::set_capacity(gendisk, self.capacity_sectors) }; + + crate::error::to_result( + // SAFETY: `gendisk` points to a valid and initialized instance of + // `struct gendisk`. + unsafe { + bindings::device_add_disk(core::ptr::null_mut(), gendisk, core::ptr::null_mut()) + }, + )?; + + // INVARIANT: `gendisk` was initialized above. + // INVARIANT: `gendisk` was added to the VFS via `device_add_disk` above. + Ok(GenDisk { + _tagset: tagset, + gendisk, + }) + } +} + +/// A generic block device. +/// +/// # Invariants +/// +/// - `gendisk` must always point to an initialized and valid `struct gendisk`. +/// - `gendisk` was added to the VFS through a call to +/// `bindings::device_add_disk`. +pub struct GenDisk<T: Operations> { + _tagset: Arc<TagSet<T>>, + gendisk: *mut bindings::gendisk, +} + +// SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a +// `TagSet` It is safe to send this to other threads as long as T is Send. +unsafe impl<T: Operations + Send> Send for GenDisk<T> {} + +impl<T: Operations> Drop for GenDisk<T> { + fn drop(&mut self) { + // SAFETY: By type invariant, `self.gendisk` points to a valid and + // initialized instance of `struct gendisk`, and it was previously added + // to the VFS. + unsafe { bindings::del_gendisk(self.gendisk) }; + } +} diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs new file mode 100644 index 000000000000..9ba7fdfeb4b2 --- /dev/null +++ b/rust/kernel/block/mq/operations.rs @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! This module provides an interface for blk-mq drivers to implement. +//! +//! C header: [`include/linux/blk-mq.h`](srctree/include/linux/blk-mq.h) + +use crate::{ + bindings, + block::mq::request::RequestDataWrapper, + block::mq::Request, + error::{from_result, Result}, + types::ARef, +}; +use core::{marker::PhantomData, sync::atomic::AtomicU64, sync::atomic::Ordering}; + +/// Implement this trait to interface blk-mq as block devices. +/// +/// To implement a block device driver, implement this trait as described in the +/// [module level documentation]. The kernel will use the implementation of the +/// functions defined in this trait to interface a block device driver. Note: +/// There is no need for an exit_request() implementation, because the `drop` +/// implementation of the [`Request`] type will be invoked by automatically by +/// the C/Rust glue logic. +/// +/// [module level documentation]: kernel::block::mq +#[macros::vtable] +pub trait Operations: Sized { + /// Called by the kernel to queue a request with the driver. If `is_last` is + /// `false`, the driver is allowed to defer committing the request. + fn queue_rq(rq: ARef<Request<Self>>, is_last: bool) -> Result; + + /// Called by the kernel to indicate that queued requests should be submitted. + fn commit_rqs(); + + /// Called by the kernel to poll the device for completed requests. Only + /// used for poll queues. + fn poll() -> bool { + crate::build_error(crate::error::VTABLE_DEFAULT_ERROR) + } +} + +/// A vtable for blk-mq to interact with a block device driver. +/// +/// A `bindings::blk_mq_ops` vtable is constructed from pointers to the `extern +/// "C"` functions of this struct, exposed through the `OperationsVTable::VTABLE`. +/// +/// For general documentation of these methods, see the kernel source +/// documentation related to `struct blk_mq_operations` in +/// [`include/linux/blk-mq.h`]. +/// +/// [`include/linux/blk-mq.h`]: srctree/include/linux/blk-mq.h +pub(crate) struct OperationsVTable<T: Operations>(PhantomData<T>); + +impl<T: Operations> OperationsVTable<T> { + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. + /// + /// # Safety + /// + /// - The caller of this function must ensure that the pointee of `bd` is + /// valid for reads for the duration of this function. + /// - This function must be called for an initialized and live `hctx`. That + /// is, `Self::init_hctx_callback` was called and + /// `Self::exit_hctx_callback()` was not yet called. + /// - `(*bd).rq` must point to an initialized and live `bindings:request`. + /// That is, `Self::init_request_callback` was called but + /// `Self::exit_request_callback` was not yet called for the request. + /// - `(*bd).rq` must be owned by the driver. That is, the block layer must + /// promise to not access the request until the driver calls + /// `bindings::blk_mq_end_request` for the request. + unsafe extern "C" fn queue_rq_callback( + _hctx: *mut bindings::blk_mq_hw_ctx, + bd: *const bindings::blk_mq_queue_data, + ) -> bindings::blk_status_t { + // SAFETY: `bd.rq` is valid as required by the safety requirement for + // this function. + let request = unsafe { &*(*bd).rq.cast::<Request<T>>() }; + + // One refcount for the ARef, one for being in flight + request.wrapper_ref().refcount().store(2, Ordering::Relaxed); + + // SAFETY: + // - We own a refcount that we took above. We pass that to `ARef`. + // - By the safety requirements of this function, `request` is a valid + // `struct request` and the private data is properly initialized. + // - `rq` will be alive until `blk_mq_end_request` is called and is + // reference counted by `ARef` until then. + let rq = unsafe { Request::aref_from_raw((*bd).rq) }; + + // SAFETY: We have exclusive access and we just set the refcount above. + unsafe { Request::start_unchecked(&rq) }; + + let ret = T::queue_rq( + rq, + // SAFETY: `bd` is valid as required by the safety requirement for + // this function. + unsafe { (*bd).last }, + ); + + if let Err(e) = ret { + e.to_blk_status() + } else { + bindings::BLK_STS_OK as _ + } + } + + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. + /// + /// # Safety + /// + /// This function may only be called by blk-mq C infrastructure. + unsafe extern "C" fn commit_rqs_callback(_hctx: *mut bindings::blk_mq_hw_ctx) { + T::commit_rqs() + } + + /// This function is called by the C kernel. It is not currently + /// implemented, and there is no way to exercise this code path. + /// + /// # Safety + /// + /// This function may only be called by blk-mq C infrastructure. + unsafe extern "C" fn complete_callback(_rq: *mut bindings::request) {} + + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. + /// + /// # Safety + /// + /// This function may only be called by blk-mq C infrastructure. + unsafe extern "C" fn poll_callback( + _hctx: *mut bindings::blk_mq_hw_ctx, + _iob: *mut bindings::io_comp_batch, + ) -> core::ffi::c_int { + T::poll().into() + } + + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. + /// + /// # Safety + /// + /// This function may only be called by blk-mq C infrastructure. This + /// function may only be called once before `exit_hctx_callback` is called + /// for the same context. + unsafe extern "C" fn init_hctx_callback( + _hctx: *mut bindings::blk_mq_hw_ctx, + _tagset_data: *mut core::ffi::c_void, + _hctx_idx: core::ffi::c_uint, + ) -> core::ffi::c_int { + from_result(|| Ok(0)) + } + + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. + /// + /// # Safety + /// + /// This function may only be called by blk-mq C infrastructure. + unsafe extern "C" fn exit_hctx_callback( + _hctx: *mut bindings::blk_mq_hw_ctx, + _hctx_idx: core::ffi::c_uint, + ) { + } + + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. + /// + /// # Safety + /// + /// - This function may only be called by blk-mq C infrastructure. + /// - `_set` must point to an initialized `TagSet<T>`. + /// - `rq` must point to an initialized `bindings::request`. + /// - The allocation pointed to by `rq` must be at the size of `Request` + /// plus the size of `RequestDataWrapper`. + unsafe extern "C" fn init_request_callback( + _set: *mut bindings::blk_mq_tag_set, + rq: *mut bindings::request, + _hctx_idx: core::ffi::c_uint, + _numa_node: core::ffi::c_uint, + ) -> core::ffi::c_int { + from_result(|| { + // SAFETY: By the safety requirements of this function, `rq` points + // to a valid allocation. + let pdu = unsafe { Request::wrapper_ptr(rq.cast::<Request<T>>()) }; + + // SAFETY: The refcount field is allocated but not initialized, so + // it is valid for writes. + unsafe { RequestDataWrapper::refcount_ptr(pdu.as_ptr()).write(AtomicU64::new(0)) }; + + Ok(0) + }) + } + + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. + /// + /// # Safety + /// + /// - This function may only be called by blk-mq C infrastructure. + /// - `_set` must point to an initialized `TagSet<T>`. + /// - `rq` must point to an initialized and valid `Request`. + unsafe extern "C" fn exit_request_callback( + _set: *mut bindings::blk_mq_tag_set, + rq: *mut bindings::request, + _hctx_idx: core::ffi::c_uint, + ) { + // SAFETY: The tagset invariants guarantee that all requests are allocated with extra memory + // for the request data. + let pdu = unsafe { bindings::blk_mq_rq_to_pdu(rq) }.cast::<RequestDataWrapper>(); + + // SAFETY: `pdu` is valid for read and write and is properly initialised. + unsafe { core::ptr::drop_in_place(pdu) }; + } + + const VTABLE: bindings::blk_mq_ops = bindings::blk_mq_ops { + queue_rq: Some(Self::queue_rq_callback), + queue_rqs: None, + commit_rqs: Some(Self::commit_rqs_callback), + get_budget: None, + put_budget: None, + set_rq_budget_token: None, + get_rq_budget_token: None, + timeout: None, + poll: if T::HAS_POLL { + Some(Self::poll_callback) + } else { + None + }, + complete: Some(Self::complete_callback), + init_hctx: Some(Self::init_hctx_callback), + exit_hctx: Some(Self::exit_hctx_callback), + init_request: Some(Self::init_request_callback), + exit_request: Some(Self::exit_request_callback), + cleanup_rq: None, + busy: None, + map_queues: None, + #[cfg(CONFIG_BLK_DEBUG_FS)] + show_rq: None, + }; + + pub(crate) const fn build() -> &'static bindings::blk_mq_ops { + &Self::VTABLE + } +} diff --git a/rust/kernel/block/mq/raw_writer.rs b/rust/kernel/block/mq/raw_writer.rs new file mode 100644 index 000000000000..9222465d670b --- /dev/null +++ b/rust/kernel/block/mq/raw_writer.rs @@ -0,0 +1,55 @@ +// SPDX-License-Identifier: GPL-2.0 + +use core::fmt::{self, Write}; + +use crate::error::Result; +use crate::prelude::EINVAL; + +/// A mutable reference to a byte buffer where a string can be written into. +/// +/// # Invariants +/// +/// `buffer` is always null terminated. +pub(crate) struct RawWriter<'a> { + buffer: &'a mut [u8], + pos: usize, +} + +impl<'a> RawWriter<'a> { + /// Create a new `RawWriter` instance. + fn new(buffer: &'a mut [u8]) -> Result<RawWriter<'a>> { + *(buffer.last_mut().ok_or(EINVAL)?) = 0; + + // INVARIANT: We null terminated the buffer above. + Ok(Self { buffer, pos: 0 }) + } + + pub(crate) fn from_array<const N: usize>( + a: &'a mut [core::ffi::c_char; N], + ) -> Result<RawWriter<'a>> { + Self::new( + // SAFETY: the buffer of `a` is valid for read and write as `u8` for + // at least `N` bytes. + unsafe { core::slice::from_raw_parts_mut(a.as_mut_ptr().cast::<u8>(), N) }, + ) + } +} + +impl Write for RawWriter<'_> { + fn write_str(&mut self, s: &str) -> fmt::Result { + let bytes = s.as_bytes(); + let len = bytes.len(); + + // We do not want to overwrite our null terminator + if self.pos + len > self.buffer.len() - 1 { + return Err(fmt::Error); + } + + // INVARIANT: We are not overwriting the last byte + self.buffer[self.pos..self.pos + len].copy_from_slice(bytes); + + self.pos += len; + + Ok(()) + } +} diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs new file mode 100644 index 000000000000..a0e22827f3f4 --- /dev/null +++ b/rust/kernel/block/mq/request.rs @@ -0,0 +1,253 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! This module provides a wrapper for the C `struct request` type. +//! +//! C header: [`include/linux/blk-mq.h`](srctree/include/linux/blk-mq.h) + +use crate::{ + bindings, + block::mq::Operations, + error::Result, + types::{ARef, AlwaysRefCounted, Opaque}, +}; +use core::{ + marker::PhantomData, + ptr::{addr_of_mut, NonNull}, + sync::atomic::{AtomicU64, Ordering}, +}; + +/// A wrapper around a blk-mq `struct request`. This represents an IO request. +/// +/// # Implementation details +/// +/// There are four states for a request that the Rust bindings care about: +/// +/// A) Request is owned by block layer (refcount 0) +/// B) Request is owned by driver but with zero `ARef`s in existence +/// (refcount 1) +/// C) Request is owned by driver with exactly one `ARef` in existence +/// (refcount 2) +/// D) Request is owned by driver with more than one `ARef` in existence +/// (refcount > 2) +/// +/// +/// We need to track A and B to ensure we fail tag to request conversions for +/// requests that are not owned by the driver. +/// +/// We need to track C and D to ensure that it is safe to end the request and hand +/// back ownership to the block layer. +/// +/// The states are tracked through the private `refcount` field of +/// `RequestDataWrapper`. This structure lives in the private data area of the C +/// `struct request`. +/// +/// # Invariants +/// +/// * `self.0` is a valid `struct request` created by the C portion of the kernel. +/// * The private data area associated with this request must be an initialized +/// and valid `RequestDataWrapper<T>`. +/// * `self` is reference counted by atomic modification of +/// self.wrapper_ref().refcount(). +/// +#[repr(transparent)] +pub struct Request<T: Operations>(Opaque<bindings::request>, PhantomData<T>); + +impl<T: Operations> Request<T> { + /// Create an `ARef<Request>` from a `struct request` pointer. + /// + /// # Safety + /// + /// * The caller must own a refcount on `ptr` that is transferred to the + /// returned `ARef`. + /// * The type invariants for `Request` must hold for the pointee of `ptr`. + pub(crate) unsafe fn aref_from_raw(ptr: *mut bindings::request) -> ARef<Self> { + // INVARIANT: By the safety requirements of this function, invariants are upheld. + // SAFETY: By the safety requirement of this function, we own a + // reference count that we can pass to `ARef`. + unsafe { ARef::from_raw(NonNull::new_unchecked(ptr as *const Self as *mut Self)) } + } + + /// Notify the block layer that a request is going to be processed now. + /// + /// The block layer uses this hook to do proper initializations such as + /// starting the timeout timer. It is a requirement that block device + /// drivers call this function when starting to process a request. + /// + /// # Safety + /// + /// The caller must have exclusive ownership of `self`, that is + /// `self.wrapper_ref().refcount() == 2`. + pub(crate) unsafe fn start_unchecked(this: &ARef<Self>) { + // SAFETY: By type invariant, `self.0` is a valid `struct request` and + // we have exclusive access. + unsafe { bindings::blk_mq_start_request(this.0.get()) }; + } + + /// Try to take exclusive ownership of `this` by dropping the refcount to 0. + /// This fails if `this` is not the only `ARef` pointing to the underlying + /// `Request`. + /// + /// If the operation is successful, `Ok` is returned with a pointer to the + /// C `struct request`. If the operation fails, `this` is returned in the + /// `Err` variant. + fn try_set_end(this: ARef<Self>) -> Result<*mut bindings::request, ARef<Self>> { + // We can race with `TagSet::tag_to_rq` + if let Err(_old) = this.wrapper_ref().refcount().compare_exchange( + 2, + 0, + Ordering::Relaxed, + Ordering::Relaxed, + ) { + return Err(this); + } + + let request_ptr = this.0.get(); + core::mem::forget(this); + + Ok(request_ptr) + } + + /// Notify the block layer that the request has been completed without errors. + /// + /// This function will return `Err` if `this` is not the only `ARef` + /// referencing the request. + pub fn end_ok(this: ARef<Self>) -> Result<(), ARef<Self>> { + let request_ptr = Self::try_set_end(this)?; + + // SAFETY: By type invariant, `this.0` was a valid `struct request`. The + // success of the call to `try_set_end` guarantees that there are no + // `ARef`s pointing to this request. Therefore it is safe to hand it + // back to the block layer. + unsafe { bindings::blk_mq_end_request(request_ptr, bindings::BLK_STS_OK as _) }; + + Ok(()) + } + + /// Return a pointer to the `RequestDataWrapper` stored in the private area + /// of the request structure. + /// + /// # Safety + /// + /// - `this` must point to a valid allocation of size at least size of + /// `Self` plus size of `RequestDataWrapper`. + pub(crate) unsafe fn wrapper_ptr(this: *mut Self) -> NonNull<RequestDataWrapper> { + let request_ptr = this.cast::<bindings::request>(); + // SAFETY: By safety requirements for this function, `this` is a + // valid allocation. + let wrapper_ptr = + unsafe { bindings::blk_mq_rq_to_pdu(request_ptr).cast::<RequestDataWrapper>() }; + // SAFETY: By C API contract, wrapper_ptr points to a valid allocation + // and is not null. + unsafe { NonNull::new_unchecked(wrapper_ptr) } + } + + /// Return a reference to the `RequestDataWrapper` stored in the private + /// area of the request structure. + pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper { + // SAFETY: By type invariant, `self.0` is a valid allocation. Further, + // the private data associated with this request is initialized and + // valid. The existence of `&self` guarantees that the private data is + // valid as a shared reference. + unsafe { Self::wrapper_ptr(self as *const Self as *mut Self).as_ref() } + } +} + +/// A wrapper around data stored in the private area of the C `struct request`. +pub(crate) struct RequestDataWrapper { + /// The Rust request refcount has the following states: + /// + /// - 0: The request is owned by C block layer. + /// - 1: The request is owned by Rust abstractions but there are no ARef references to it. + /// - 2+: There are `ARef` references to the request. + refcount: AtomicU64, +} + +impl RequestDataWrapper { + /// Return a reference to the refcount of the request that is embedding + /// `self`. + pub(crate) fn refcount(&self) -> &AtomicU64 { + &self.refcount + } + + /// Return a pointer to the refcount of the request that is embedding the + /// pointee of `this`. + /// + /// # Safety + /// + /// - `this` must point to a live allocation of at least the size of `Self`. + pub(crate) unsafe fn refcount_ptr(this: *mut Self) -> *mut AtomicU64 { + // SAFETY: Because of the safety requirements of this function, the + // field projection is safe. + unsafe { addr_of_mut!((*this).refcount) } + } +} + +// SAFETY: Exclusive access is thread-safe for `Request`. `Request` has no `&mut +// self` methods and `&self` methods that mutate `self` are internally +// synchronized. +unsafe impl<T: Operations> Send for Request<T> {} + +// SAFETY: Shared access is thread-safe for `Request`. `&self` methods that +// mutate `self` are internally synchronized` +unsafe impl<T: Operations> Sync for Request<T> {} + +/// Store the result of `op(target.load())` in target, returning new value of +/// target. +fn atomic_relaxed_op_return(target: &AtomicU64, op: impl Fn(u64) -> u64) -> u64 { + let old = target.fetch_update(Ordering::Relaxed, Ordering::Relaxed, |x| Some(op(x))); + + // SAFETY: Because the operation passed to `fetch_update` above always + // return `Some`, `old` will always be `Ok`. + let old = unsafe { old.unwrap_unchecked() }; + + op(old) +} + +/// Store the result of `op(target.load)` in `target` if `target.load() != +/// pred`, returning true if the target was updated. +fn atomic_relaxed_op_unless(target: &AtomicU64, op: impl Fn(u64) -> u64, pred: u64) -> bool { + target + .fetch_update(Ordering::Relaxed, Ordering::Relaxed, |x| { + if x == pred { + None + } else { + Some(op(x)) + } + }) + .is_ok() +} + +// SAFETY: All instances of `Request<T>` are reference counted. This +// implementation of `AlwaysRefCounted` ensure that increments to the ref count +// keeps the object alive in memory at least until a matching reference count +// decrement is executed. +unsafe impl<T: Operations> AlwaysRefCounted for Request<T> { + fn inc_ref(&self) { + let refcount = &self.wrapper_ref().refcount(); + + #[cfg_attr(not(CONFIG_DEBUG_MISC), allow(unused_variables))] + let updated = atomic_relaxed_op_unless(refcount, |x| x + 1, 0); + + #[cfg(CONFIG_DEBUG_MISC)] + if !updated { + panic!("Request refcount zero on clone") + } + } + + unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) { + // SAFETY: The type invariants of `ARef` guarantee that `obj` is valid + // for read. + let wrapper_ptr = unsafe { Self::wrapper_ptr(obj.as_ptr()).as_ptr() }; + // SAFETY: The type invariant of `Request` guarantees that the private + // data area is initialized and valid. + let refcount = unsafe { &*RequestDataWrapper::refcount_ptr(wrapper_ptr) }; + + #[cfg_attr(not(CONFIG_DEBUG_MISC), allow(unused_variables))] + let new_refcount = atomic_relaxed_op_return(refcount, |x| x - 1); + + #[cfg(CONFIG_DEBUG_MISC)] + if new_refcount == 0 { + panic!("Request reached refcount zero in Rust abstractions"); + } + } +} diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs new file mode 100644 index 000000000000..f9a1ca655a35 --- /dev/null +++ b/rust/kernel/block/mq/tag_set.rs @@ -0,0 +1,86 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! This module provides the `TagSet` struct to wrap the C `struct blk_mq_tag_set`. +//! +//! C header: [`include/linux/blk-mq.h`](srctree/include/linux/blk-mq.h) + +use core::pin::Pin; + +use crate::{ + bindings, + block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations}, + error, + prelude::PinInit, + try_pin_init, + types::Opaque, +}; +use core::{convert::TryInto, marker::PhantomData}; +use macros::{pin_data, pinned_drop}; + +/// A wrapper for the C `struct blk_mq_tag_set`. +/// +/// `struct blk_mq_tag_set` contains a `struct list_head` and so must be pinned. +/// +/// # Invariants +/// +/// - `inner` is initialized and valid. +#[pin_data(PinnedDrop)] +#[repr(transparent)] +pub struct TagSet<T: Operations> { + #[pin] + inner: Opaque<bindings::blk_mq_tag_set>, + _p: PhantomData<T>, +} + +impl<T: Operations> TagSet<T> { + /// Try to create a new tag set + pub fn new( + nr_hw_queues: u32, + num_tags: u32, + num_maps: u32, + ) -> impl PinInit<Self, error::Error> { + // SAFETY: `blk_mq_tag_set` only contains integers and pointers, which + // all are allowed to be 0. + let tag_set: bindings::blk_mq_tag_set = unsafe { core::mem::zeroed() }; + let tag_set = core::mem::size_of::<RequestDataWrapper>() + .try_into() + .map(|cmd_size| { + bindings::blk_mq_tag_set { + ops: OperationsVTable::<T>::build(), + nr_hw_queues, + timeout: 0, // 0 means default which is 30Hz in C + numa_node: bindings::NUMA_NO_NODE, + queue_depth: num_tags, + cmd_size, + flags: bindings::BLK_MQ_F_SHOULD_MERGE, + driver_data: core::ptr::null_mut::<core::ffi::c_void>(), + nr_maps: num_maps, + ..tag_set + } + }); + + try_pin_init!(TagSet { + inner <- PinInit::<_, error::Error>::pin_chain(Opaque::new(tag_set?), |tag_set| { + // SAFETY: we do not move out of `tag_set`. + let tag_set = unsafe { Pin::get_unchecked_mut(tag_set) }; + // SAFETY: `tag_set` is a reference to an initialized `blk_mq_tag_set`. + error::to_result( unsafe { bindings::blk_mq_alloc_tag_set(tag_set.get())}) + }), + _p: PhantomData, + }) + } + + /// Return the pointer to the wrapped `struct blk_mq_tag_set` + pub(crate) fn raw_tag_set(&self) -> *mut bindings::blk_mq_tag_set { + self.inner.get() + } +} + +#[pinned_drop] +impl<T: Operations> PinnedDrop for TagSet<T> { + fn drop(self: Pin<&mut Self>) { + // SAFETY: By type invariant `inner` is valid and has been properly + // initialized during construction. + unsafe { bindings::blk_mq_free_tag_set(self.inner.get()) }; + } +} diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 55280ae9fe40..145f5c397009 100644 --- a/rust/kernel/error.rs +++ b/rust/kernel/error.rs @@ -126,6 +126,12 @@ impl Error { self.0 } + #[cfg(CONFIG_BLOCK)] + pub(crate) fn to_blk_status(self) -> bindings::blk_status_t { + // SAFETY: `self.0` is a valid error due to its invariant. + unsafe { bindings::errno_to_blk_status(self.0) } + } + /// Returns the error encoded as a pointer. #[allow(dead_code)] pub(crate) fn to_ptr<T>(self) -> *mut T { diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index fbd91a48ff8b..2cf7c6b6f66b 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -27,6 +27,8 @@ compile_error!("Missing kernel configuration for conditional compilation"); extern crate self as kernel; pub mod alloc; +#[cfg(CONFIG_BLOCK)] +pub mod block; mod build_assert; pub mod error; pub mod init; |