kernel/linux.git/include/linux/libata.h, branch v6.19.11

ata: libata-scsi: avoid Non-NCQ command starvation

2026-02-26T23:01:40+00:00

commit 0ea84089dbf62a92dc7889c79e6b18fc89260808 upstream. When a non-NCQ command is issued while NCQ commands are being executed, ata_scsi_qc_issue() indicates to the SCSI layer that the command issuing should be deferred by returning SCSI_MLQUEUE_XXX_BUSY. This command deferring is correct and as mandated by the ACS specifications since NCQ and non-NCQ commands cannot be mixed. However, in the case of a host adapter using multiple submission queues, when the target device is under a constant load of NCQ commands, there are no guarantees that requeueing the non-NCQ command will be executed later and it may be deferred again repeatedly as other submission queues can constantly issue NCQ commands from different CPUs ahead of the non-NCQ command. This can lead to very long delays for the execution of non-NCQ commands, and even complete starvation for these commands in the worst case scenario. Since the block layer and the SCSI layer do not distinguish between queueable (NCQ) and non queueable (non-NCQ) commands, libata-scsi SAT implementation must ensure forward progress for non-NCQ commands in the presence of NCQ command traffic. This is similar to what SAS HBAs with a hardware/firmware based SAT implementation do. Implement such forward progress guarantee by limiting requeueing of non-NCQ commands from ata_scsi_qc_issue(): when a non-NCQ command is received and NCQ commands are in-flight, do not force a requeue of the non-NCQ command by returning SCSI_MLQUEUE_XXX_BUSY and instead return 0 to indicate that the command was accepted but hold on to the qc using the new deferred_qc field of struct ata_port. This deferred qc will be issued using the work item deferred_qc_work running the function ata_scsi_deferred_qc_work() once all in-flight commands complete, which is checked with the port qc_defer() callback return value indicating that no further delay is necessary. This check is done using the helper function ata_scsi_schedule_deferred_qc() which is called from ata_scsi_qc_complete(). This thus excludes this mechanism from all internal non-NCQ commands issued by ATA EH. When a port deferred_qc is non NULL, that is, the port has a command waiting for the device queue to drain, the issuing of all incoming commands (both NCQ and non-NCQ) is deferred using the regular busy mechanism. This simplifies the code and also avoids potential denial of service problems if a user issues too many non-NCQ commands. Finally, whenever ata EH is scheduled, regardless of the reason, a deferred qc is always requeued so that it can be retried once EH completes. This is done by calling the function ata_scsi_requeue_deferred_qc() from ata_eh_set_pending(). This avoids the need for any special processing for the deferred qc in case of NCQ error, link or device reset, or device timeout. Reported-by: Xingui Yang Reported-by: Igor Pylypiv Fixes: bdb01301f3ea ("scsi: Add host and host template flag 'host_tagset'") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Martin K. Petersen Reviewed-by: John Garry Tested-by: Igor Pylypiv Tested-by: Xingui Yang Signed-off-by: Greg Kroah-Hartman

ata: libata: Add ATA_QUIRK_MAX_SEC and convert all device quirks

2026-02-26T23:01:17+00:00

[ Upstream commit 59b7bb3d48333889adb1dd2aac3ab0cf26714390 ] Add a new quirk ATA_QUIRK_MAX_SEC, which has a separate table with device specific values. Convert all existing ATA_QUIRK_MAX_SEC_XXX device quirks in __ata_dev_quirks to the new format. Quirks ATA_QUIRK_MAX_SEC_128 and ATA_QUIRK_MAX_SEC_1024 cannot be removed yet, since they are also used by libata.force, which functionally, is a separate user of the quirks. The quirks will be removed once all users have been converted to use the new format. The quirk ATA_QUIRK_MAX_SEC_8191 can be removed since it has no equivalent libata.force parameter. Signed-off-by: Niklas Cassel Reviewed-by: Damien Le Moal Reviewed-by: Martin K. Petersen Signed-off-by: Damien Le Moal Stable-dep-of: 5f64ae1ef639 ("ata: libata-core: Quirk INTEL SSDSC2KG480G8 max_sectors") Signed-off-by: Sasha Levin

Merge tag 'ata-6.19-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux

2025-12-06T04:41:20+00:00

Pull ata fix from Niklas Cassel: - The DELLBOSS VD SATA controller times out when sending I/Os of size 4096 KiB or larger, even though it claims LBA48 support, which per the ACS standard requires support for a maximum command size of 65535 sectors, i.e. 32 MiB - 512. Thus, quirk the device so that it sets a lower maximum command size (me) * tag 'ata-6.19-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux: ata: libata-core: Quirk DELLBOSS VD max_sectors ata: libata: Move quirk flags to their own enum

ata: libata-core: Quirk DELLBOSS VD max_sectors

2025-12-02T10:17:56+00:00

Commit 9b8b84879d4a ("block: Increase BLK_DEF_MAX_SECTORS_CAP") increased the default max_sectors_kb from 1280 KiB to 4096 KiB. DELLBOSS VD with FW rev MV.R00-0 times out when sending I/Os of size 4096 KiB. Enable ATA_QUIRK_MAX_SEC, with value 8191 (sectors) for this device, since any I/O with more sectors than that lead to I/O timeouts. With this, the DELLBOSS VD SATA controller is usable again. Cc: stable+noautosel@kernel.org # depends on Move quirk flags to their own enum Fixes: 9b8b84879d4a ("block: Increase BLK_DEF_MAX_SECTORS_CAP") Reviewed-by: Damien Le Moal Signed-off-by: Niklas Cassel

ata: libata: Move quirk flags to their own enum

2025-12-02T10:17:56+00:00

The anonymous enum in include/linux/libata.h that is used to store various global constants can currently be backed by type int. (It contains both negative and positive constants.) __ATA_QUIRK_MAX is currently 31. The quirk flags in the various global constants enum are defined as "1U << quirk_flag_bit". Thus if we simply add an additional quirk, the quirk flag will be 1 << 31, which is a value that is too large to be represented by a signed int. The various global constants enum will thus therefore be backed by type long. This will lead to error prints like e.g.: ata_port_err(ap, "EH pending after %d tries, giving up\n", ATA_EH_MAX_TRIES); now failing to build, with build error: error: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘long int’ [-Werror=format=] This is because all constants in the various global constants enum now has to be printed as a long, as that is now the backing type of the enum. Since the compiler will use the smallest possible backing type for an enum, it is good practice to not mix unrelated things in a single enum. Move the quirk flags to a separate enum, so that we don't need to change the printf specifier for all other constants in the "various global constants" enum when adding an additional quirk. Reviewed-by: Damien Le Moal Reviewed-by: Martin K. Petersen Signed-off-by: Niklas Cassel

ata: libata-core: relax checks in ata_read_log_directory()

2025-10-13T07:12:36+00:00

Commit 6d4405b16d37 ("ata: libata-core: Cache the general purpose log directory") introduced caching of a device general purpose log directory to avoid repeated access to this log page during device scan. This change also added a check on this log page to verify that the log page version is 0x0001 as mandated by the ACS specifications. And it turns out that some devices do not bother reporting this version, instead reporting a version 0, resulting in error messages such as: ata6.00: Invalid log directory version 0x0000 and to the device being marked as not supporting the general purpose log directory log page. Since before commit 6d4405b16d37 the log page version check did not exist and things were still working correctly for these devices, relax ata_read_log_directory() version check and only warn about the invalid log page version number without disabling access to the log directory page. Fixes: 6d4405b16d37 ("ata: libata-core: Cache the general purpose log directory") Cc: stable@vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220635 Signed-off-by: Damien Le Moal Signed-off-by: Niklas Cassel

scsi: switch ->bios_param() to passing gendisk

2025-08-13T06:59:28+00:00

Instances are passed struct block_device *bdev argument; the only thing it is used for (if it's used in the first place) is bdev->bd_disk. Might as well pass that in the first place... Reviewed-by: Martin K. Petersen Reviewed-by: Christoph Hellwig Acked-by: Jens Axboe Signed-off-by: Al Viro

ata: libata-sata: Add link_power_management_supported sysfs attribute

2025-07-31T03:56:21+00:00

A port link power management (LPM) policy can be controlled using the link_power_management_policy sysfs host attribute. However, this attribute exists also for hosts that do not support LPM and in such case, attempting to change the LPM policy for the host (port) will fail with -EOPNOTSUPP. Introduce the new sysfs link_power_management_supported host attribute to indicate to the user if a the port and the devices connected to the port for the host support LPM, which implies that the link_power_management_policy attribute can be used. Since checking that a port and its devices support LPM is common between the new ata_scsi_lpm_supported_show() function and the existing ata_scsi_lpm_store() function, the new helper ata_scsi_lpm_supported() is introduced. Fixes: 413e800cadbf ("ata: libata-sata: Disallow changing LPM state if not supported") Reported-by: Borah, Chaitanya Kumar Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202507251014.a5becc3b-lkp@intel.com Signed-off-by: Damien Le Moal Reviewed-by: Martin K. Petersen

ata: libata-eh: Simplify reset operation management

2025-07-16T07:31:43+00:00

Introduce struct ata_reset_operations to aggregate in a single structure the definitions of the 4 reset methods (prereset, softreset, hardreset and postreset) for a port. This new structure is used in struct ata_port to define the reset methods for a regular port (reset field) and for a port-multiplier port (pmp_reset field). A pointer to either of these fields replaces the 4 reset method arguments passed to ata_eh_recover() and ata_eh_reset(). The definition of the reset methods for all drivers is changed to use the reset and pmp_reset fields in struct ata_port_operations. A large number of files is modifed, but no functional changes are introduced. Suggested-by: Niklas Cassel Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20250716020315.235457-3-dlemoal@kernel.org Signed-off-by: Niklas Cassel

ata: libata-eh: Remove ata_do_eh()

2025-07-16T07:31:43+00:00

The only reason for ata_do_eh() to exist is that the two caller sites, ata_std_error_handler() and ata_sff_error_handler() may pass it a NULL hardreset operation so that the built-in (generic) hardreset operation for a driver is ignored if the adapter SCR access is not available. However, ata_std_error_handler() and ata_sff_error_handler() modifications of the hardreset port operation can easily be combined as they are mutually exclusive. That is, a driver using sata_std_hardreset() as its hardreset operation cannot use sata_sff_hardreset() and vice-versa. With this observation, ata_do_eh() can be removed and its code moved to ata_std_error_handler(). The condition used to ignore the built-in hardreset port operation is modified to be the one that was used in ata_sff_error_handler(). This requires defining a stub for the function sata_sff_hardreset() to avoid compilation errors when CONFIG_ATA_SFF is not enabled. Furthermore, instead of modifying the local hardreset operation definition, set the ATA_LFLAG_NO_HRST link flag to prevent the use of built-in hardreset methods for ports without a valid scr_read function. This flag is checked in ata_eh_reset() and if set, the hardreset method is ignored. This change simplifies ata_sff_error_handler() as this function now only needs to call ata_std_error_handler(). No functional changes. Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20250716020315.235457-2-dlemoal@kernel.org Signed-off-by: Niklas Cassel