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Now that sem, msgque and shm, through *_down(), all use the lockless
variant of ipcctl_pre_down(), go ahead and delete it.
[[email protected]: fix function name in kerneldoc, cleanups]
Signed-off-by: Davidlohr Bueso <[email protected]>
Tested-by: Sedat Dilek <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Manfred Spraul <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Instead of holding the ipc lock for the entire function, use the
ipcctl_pre_down_nolock and only acquire the lock for specific commands:
RMID and SET.
Signed-off-by: Davidlohr Bueso <[email protected]>
Tested-by: Sedat Dilek <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Manfred Spraul <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This is the third and final patchset that deals with reducing the amount
of contention we impose on the ipc lock (kern_ipc_perm.lock). These
changes mostly deal with shared memory, previous work has already been
done for semaphores and message queues:
http://lkml.org/lkml/2013/3/20/546 (sems)
http://lkml.org/lkml/2013/5/15/584 (mqueues)
With these patches applied, a custom shm microbenchmark stressing shmctl
doing IPC_STAT with 4 threads a million times, reduces the execution
time by 50%. A similar run, this time with IPC_SET, reduces the
execution time from 3 mins and 35 secs to 27 seconds.
Patches 1-8: replaces blindly taking the ipc lock for a smarter
combination of rcu and ipc_obtain_object, only acquiring the spinlock
when updating.
Patch 9: renames the ids rw_mutex to rwsem, which is what it already was.
Patch 10: is a trivial mqueue leftover cleanup
Patch 11: adds a brief lock scheme description, requested by Andrew.
This patch:
Add shm_obtain_object() and shm_obtain_object_check(), which will allow us
to get the ipc object without acquiring the lock. Just as with other
forms of ipc, these functions are basically wrappers around
ipc_obtain_object*().
Signed-off-by: Davidlohr Bueso <[email protected]>
Tested-by: Sedat Dilek <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Manfred Spraul <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Command line option rootfstype=ramfs to obtain old initramfs behavior, and
use ramfs instead of tmpfs for stub when root= defined (for cosmetic
reasons).
[[email protected]: coding-style fixes]
Signed-off-by: Rob Landley <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Stephen Warren <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Jim Cromie <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Conditionally call the appropriate fs_init function and fill_super
functions. Add a use once guard to shmem_init() to simply succeed on a
second call.
(Note that IS_ENABLED() is a compile time constant so dead code
elimination removes unused function calls when CONFIG_TMPFS is disabled.)
Signed-off-by: Rob Landley <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Stephen Warren <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Jim Cromie <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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When the rootfs code was a wrapper around ramfs, having them in the same
file made sense. Now that it can wrap another filesystem type, move it in
with the init code instead.
This also allows a subsequent patch to access rootfstype= command line
arg.
Signed-off-by: Rob Landley <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Stephen Warren <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Jim Cromie <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Even though ramfs hasn't got a backing device, commit e0bf68ddec4f ("mm:
bdi init hooks") added one anyway, and put the initialization in
init_rootfs() since that's the first user, leaving it out of init_ramfs()
to avoid duplication.
But initmpfs uses init_tmpfs() instead, so move the init into the
filesystem's init function, add a "once" guard to prevent duplicate
initialization, and call the filesystem init from rootfs init.
This goes part of the way to allowing ramfs to be built as a module.
[[email protected]; using bit 1 was odd]
Signed-off-by: Rob Landley <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Stephen Warren <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Jim Cromie <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Mounting MS_NOUSER prevents --bind mounts from rootfs. Prevent new rootfs
mounts with a different mechanism that doesn't affect bind mounts.
Signed-off-by: Rob Landley <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Stephen Warren <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Jim Cromie <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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With users of radix_tree_preload() run from interrupt (block/blk-ioc.c is
one such possible user), the following race can happen:
radix_tree_preload()
...
radix_tree_insert()
radix_tree_node_alloc()
if (rtp->nr) {
ret = rtp->nodes[rtp->nr - 1];
<interrupt>
...
radix_tree_preload()
...
radix_tree_insert()
radix_tree_node_alloc()
if (rtp->nr) {
ret = rtp->nodes[rtp->nr - 1];
And we give out one radix tree node twice. That clearly results in radix
tree corruption with different results (usually OOPS) depending on which
two users of radix tree race.
We fix the problem by making radix_tree_node_alloc() always allocate fresh
radix tree nodes when in interrupt. Using preloading when in interrupt
doesn't make sense since all the allocations have to be atomic anyway and
we cannot steal nodes from process-context users because some users rely
on radix_tree_insert() succeeding after radix_tree_preload().
in_interrupt() check is somewhat ugly but we cannot simply key off passed
gfp_mask as that is acquired from root_gfp_mask() and thus the same for
all preload users.
Another part of the fix is to avoid node preallocation in
radix_tree_preload() when passed gfp_mask doesn't allow waiting. Again,
preallocation in such case doesn't make sense and when preallocation would
happen in interrupt we could possibly leak some allocated nodes. However,
some users of radix_tree_preload() require following radix_tree_insert()
to succeed. To avoid unexpected effects for these users,
radix_tree_preload() only warns if passed gfp mask doesn't allow waiting
and we provide a new function radix_tree_maybe_preload() for those users
which get different gfp mask from different call sites and which are
prepared to handle radix_tree_insert() failure.
Signed-off-by: Jan Kara <[email protected]>
Cc: Jens Axboe <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The driver core clears the driver data to NULL after device_release or on
probe failure. Thus, it is not needed to manually clear the device driver
data to NULL.
Signed-off-by: Jingoo Han <[email protected]>
Cc: Evgeniy Polyakov <[email protected]>
Cc: Greg KH <[email protected]>
Acked-by: Shawn Guo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The usage of strict_strtol() is not preferred, because strict_strtol() is
obsolete. Thus, kstrtol() should be used.
Signed-off-by: Jingoo Han <[email protected]>
Cc: Evgeniy Polyakov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Based partially on MS standard spec quotes from Alex Dubov.
As any code that works with user data this driver isn't recommended to use
to write cards that contain valuable data.
It tries its best though to avoid data corruption and possible damage to
the card.
Tested on MS DUO 64 MB card on Ricoh R592 card reader.
Signed-off-by: Maxim Levitsky <[email protected]>
Cc: Valdis Kletnieks <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Tejun Heo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The driver core clears the driver data to NULL after device_release or on
probe failure. Thus, it is not needed to manually clear the device driver
data to NULL.
Signed-off-by: Jingoo Han <[email protected]>
Cc: Maxim Levitsky <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The driver core clears the driver data to NULL after device_release or on
probe failure. Thus, it is not needed to manually clear the device driver
data to NULL.
Signed-off-by: Jingoo Han <[email protected]>
Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Fix thinkos where pkt_<level> needs a valid pktcdvd_device * and the
pointer is known to be NULL.
Signed-off-by: Joe Perches <[email protected]>
Reported-by: Dan Carpenter <[email protected]> (go smatch!)
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Allow the device name to be emitted with pkt_err when logging the sense
data.
Signed-off-by: Joe Perches <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add a new pkt_info macro to prefix the name to the logging output.
Signed-off-by: Joe Perches <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add a new pkt_notice macro to prefix the name to the logging output.
Signed-off-by: Joe Perches <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add a new pkt_err macro to prefix the name to the logging output. Convert
pr_err where there is a non-null struct pktcdvd_device.
Includes improvements from Andy Shevchenko.
Signed-off-by: Joe Perches <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add pd->name to output for these debugging messages.
Remove normally compiled out pkt_dbg(2, ...) function entry tracing
equivalents as it's better done via the function tracer.
Signed-off-by: Joe Perches <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Use the more common pkt_dbg(level, fmt, ...) form.
These messages are emitted at KERN_NOTICE.
Always emit function name with pkt_dbg(2, ...) uses and remove the
sometimes abbreviated embedded function name.
This form always verifies the format and arguments.
Signed-off-by: Joe Perches <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Use a more current logging style and add messages levels to the logging
messages.
Simplify pkt_dump_sense by using %*ph and adding a simple function to emit
the sense string.
Includes improvements from Andy Shevchenko and Dan Carpenter.
Signed-off-by: Joe Perches <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Macros should be converted to functions where feasible to
verify arguments and the like.
Signed-off-by: Joe Perches <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Since the panic handlers may produce additional information (via printk)
for the kernel log, it should be reported as part of the panic output
saved by kmsg_dump(). Without this re-ordering, nothing that adds
information to a panic will show up in pstore's view when kmsg_dump runs,
and is therefore not visible to crash reporting tools that examine pstore
output.
Signed-off-by: Kees Cook <[email protected]>
Cc: Anton Vorontsov <[email protected]>
Cc: Colin Cross <[email protected]>
Acked-by: Tony Luck <[email protected]>
Cc: Stephen Boyd <[email protected]>
Cc: Vikram Mulukutla <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rusty Russell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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It seems pretty unlikely that AFFS supports files over 4GB but we may as
well leave use loff_t just for cleanness sake instead of truncating it to
32 bits.
Signed-off-by: Dan Carpenter <[email protected]>
Cc: Marco Stornelli <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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When the example udev rules in the documentation are used without
modification, warnings like the one shown below appear in the system logs:
/var/log/messages:Aug 22 11:09:11 kung udevd[445]: NAME="%k" \
is superfluous and breaks kernel supplied names, please remove \
it from /etc/udev/rules.d/60-aoe.rules:26
Removing the term does not cause any problems with the creation of the
special character and block device nodes.
Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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If the system has trouble allocating memory for the creation of the aoe
debugfs directory or of a file inside it, the debugfs member of an aoedev
can be NULL.
Do not treat a NULL debugfs pointer as a BUG on aoedev shutdown, avoiding
the user impact of an unecessary panic.
Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This patch fixes following compiler warnings:
drivers/block/aoe/aoecmd.c: In function `aoecmd_ata_rw':
drivers/block/aoe/aoecmd.c:383:17: warning: variable `t' set but not used [-Wunused-but-set-variable]
struct aoetgt *t;
^
drivers/block/aoe/aoecmd.c: In function `resend':
drivers/block/aoe/aoecmd.c:488:21: warning: variable `ah' set but not used [-Wunused-but-set-variable]
struct aoe_atahdr *ah;
^
Signed-off-by: Andy Shevchenko <[email protected]>
Cc: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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In the kernel we have a nice helper that may be used here. This patch
substitutes the custom implementation by the native function call.
Signed-off-by: Andy Shevchenko <[email protected]>
Cc: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Introduced module params to provide dynamic way of configuring
queue depth.
Added support to get max io throttle count through UCSM to
configure maximum outstanding IOs supported by fnic and push
that value to scsi mid-layer.
Supported IO throttle values:
UCSM IO THROTTLE VALUE FNIC MAX OUTSTANDING IOS
------------------------------------------------------
16 (Default) 2048
<= 256 256
> 256 <ucsm value>
Signed-off-by: Hiral Patel <[email protected]>
Signed-off-by: James Bottomley <[email protected]>
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Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This information is presented in a compact format that has evolved for
easy routine scanning by expert humans, mostly developers and support
technicians helping to troubleshoot or test AoE-based systems.
Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The place holder in the file contents is filled out in the following
patch.
Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This series adds the debugging information that the coraid.com-distributed
aoe driver exports via sysfs, but instead of sysfs, it uses debugfs.
With these patches applied, even without AoE targets on the network, KEDR
reports new possible memory leaks, but these are from callers outside the
aoe driver that have used aoe_devnode to get the name of the character
devices through the aoe_class->devnode callback, and I believe they're
responsible for freeing that memory.
This patch:
Create and destroy the debugfs directory.
Signed-off-by: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Signed-off-by: Cody P Schafer <[email protected]>
Reviewed-by: Seth Jennings <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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No reason require rbtree test code to be a module, allow it to be builtin
(streamlines my development process)
Signed-off-by: Cody P Schafer <[email protected]>
Reviewed-by: Seth Jennings <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Just check that we examine all nodes in the tree for the postorder
iteration.
Signed-off-by: Cody P Schafer <[email protected]>
Reviewed-by: Seth Jennings <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Because deletion (of the entire tree) is a relatively common use of the
rbtree_postorder iteration, and because doing it safely means fiddling
with temporary storage, provide a helper to simplify postorder rbtree
iteration.
Signed-off-by: Cody P Schafer <[email protected]>
Reviewed-by: Seth Jennings <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Postorder iteration yields all of a node's children prior to yielding the
node itself, and this particular implementation also avoids examining the
leaf links in a node after that node has been yielded.
In what I expect will be its most common usage, postorder iteration allows
the deletion of every node in an rbtree without modifying the rbtree nodes
(no _requirement_ that they be nulled) while avoiding referencing child
nodes after they have been "deleted" (most commonly, freed).
I have only updated zswap to use this functionality at this point, but
numerous bits of code (most notably in the filesystem drivers) use a hand
rolled postorder iteration that NULLs child links as it traverses the
tree. Each of those instances could be replaced with this common
implementation.
1 & 2 add rbtree postorder iteration functions.
3 adds testing of the iteration to the rbtree runtime tests
4 allows building the rbtree runtime tests as builtins
5 updates zswap.
This patch:
Add postorder iteration functions for rbtree. These are useful for safely
freeing an entire rbtree without modifying the tree at all.
Signed-off-by: Cody P Schafer <[email protected]>
Reviewed-by: Seth Jennings <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Cc: Davidlohr Bueso <[email protected]>
Cc: Karel Zak <[email protected]>
Cc: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Trivial coding style cleanups - still plenty left.
[[email protected]: coding-style fixes]
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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I love emacs, but these settings for coding style are annoying when trying
to open the efi.h file. More important, we already have checkpatch for
that.
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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When verifying GPT header integrity, make sure that first usable LBA is
smaller than last usable LBA.
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The partition that has the 0xEE (GPT protective), must have the size in
lba field set to the lesser of the size of the disk minus one or
0xFFFFFFFF for larger disks.
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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One of the biggest problems with GPT is compatibility with older, non-GPT
systems. The problem is addressed by creating hybrid mbrs, an extension,
or variant, of the traditional protective mbr. This contains, apart from
the 0xEE partition, up three additional primary partitions that point to
the same space marked by up to three GPT partitions. The result is that
legacy OSs can see the three required MBR partitions and at the same time
ignore the GPT-aware partitions that protect the GPT structures.
While hybrid MBRs are hacks, workarounds and simply not part of the GPT
standard, they do exist and we have no way around them. For instance, by
default, OSX creates a hybrid scheme when using multi-OS booting.
In order for Linux to properly discover protective MBRs, it must be made
aware of devices that have hybrid MBRs. No functionality is changed by
this patch, just a debug message informing the user of the MBR scheme that
is being used.
[[email protected]: coding-style fixes]
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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When detecting a valid protective MBR, the Linux kernel isn't picky about
the partition (1-4) the 0xEE is at, but, unlike other operating systems,
it does require it to begin at the second sector (sector 1). This check,
apart from it not being enforced by UEFI, and causing Linux to potentially
fail to detect any *valid* partitions on the disk, can present problems
when dealing with hybrid MBRs[1].
For compatibility reasons, if the first partition is hybridized, the 0xEE
partition must be small enough to ensure that it only protects the GPT
data structures - as opposed to the the whole disk in a protective MBR.
This problem is very well described by Rod Smith[1]: where MBR-only
partitioning programs (such as older versions of fdisk) can see some of
the disk space as unallocated, thus loosing the purpose of the 0xEE
partition's protection of GPT data structures.
By dropping this check, this patch enables Linux to be more flexible when
probing for GPT disklabels.
[1] http://www.rodsbooks.com/gdisk/hybrid.html#reactions
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Per the UEFI Specs 2.4, June 2013, the starting lba of the partition that
has the EFI GPT (0xEE) must be set to 0x00000001 - this is obviously the
LBA of the GPT Partition Header.
[[email protected]: coding-style fixes]
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The kernel's GPT implementation currently uses the generic 'struct
partition' type for dealing with legacy MBR partition records. While this
is is useful for disklabels that we designed for CHS addressing, such as
msdos, it doesn't adapt well to newer standards that use LBA instead, such
as GUID partition tables. Furthermore, these generic partition structures
do not have all the required fields to properly follow the UEFI specs.
While a CHS address can be translated to LBA, it's much simpler and
cleaner to just replace the partition type. This patch adds a new
'gpt_record' type that is fully compliant with EFI and will allow, in the
next patches, to add more checks to properly verify a protective MBR,
which is paramount to probing a device that makes use of GPT.
[[email protected]: coding-style fixes]
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Karel Zak <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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