ata: libata: Improve CDL resource management

The ncq_sense_buf buffer field of struct ata_port is allocated and used
only for devices that support the Command Duration Limits (CDL) feature.
However, the cdl buffer of struct ata_device, which is used to cache the
command duration limits log page for devices supporting CDL is always
allocated as part of struct ata_device, which is wasteful of memory for
devices that do not support this feature.

Clean this up by defining both buffers as part of the new ata_cdl
structure and allocating this structure only for devices that support
the CDL feature. This new structure is attached to struct ata_device
using the cdl pointer.

The functions ata_dev_init_cdl_resources() and
ata_dev_cleanup_cdl_resources() are defined to manage this new structure
allocation, initialization and freeing when a port is removed or a
device disabled. ata_dev_init_cdl_resources() is called from
ata_dev_config_cdl() only for devices that support CDL.
ata_dev_cleanup_cdl_resources() is called from ata_dev_free_resources()
to free the ata_cdl structure when a device is being disabled by EH.

Note that the name of the former cdl log buffer of struct ata_device is
changed to desc_log_buf to make it clearer that it is a buffer for the
limit descriptors log page.

This change reduces the size of struct ata_device, thus reducing memory
usage for ATA devices that do not support the CDL feature.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index 498430db86f7..c8b119a06bb2 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -1505,7 +1505,7 @@ int ata_eh_get_ncq_success_sense(struct ata_link *link)
 {
 	struct ata_device *dev = link->device;
 	struct ata_port *ap = dev->link->ap;
-	u8 *buf = ap->ncq_sense_buf;
+	u8 *buf = dev->cdl->ncq_sense_log_buf;
 	struct ata_queued_cmd *qc;
 	unsigned int err_mask, tag;
 	u8 *sense, sk = 0, asc = 0, ascq = 0;