kernel/drivers/ata/libata-scsi.c, branch linux-rolling-lts

ata: libata: cancel pending work after clearing deferred_qc

2026-03-13T16:23:30Z

commit aac9b27f7c1f2b2cf7f50a9ca633ecbbcaf22af9 upstream. Syzbot reported a WARN_ON() in ata_scsi_deferred_qc_work(), caused by ap->ops->qc_defer() returning non-zero before issuing the deferred qc. ata_scsi_schedule_deferred_qc() is called during each command completion. This function will check if there is a deferred QC, and if ap->ops->qc_defer() returns zero, meaning that it is possible to queue the deferred qc at this time (without being deferred), then it will queue the work which will issue the deferred qc. Once the work get to run, which can potentially be a very long time after the work was scheduled, there is a WARN_ON() if ap->ops->qc_defer() returns non-zero. While we hold the ap->lock both when assigning and clearing deferred_qc, and the work itself holds the ap->lock, the code currently does not cancel the work after clearing the deferred qc. This means that the following scenario can happen: 1) One or several NCQ commands are queued. 2) A non-NCQ command is queued, gets stored in ap->deferred_qc. 3) Last NCQ command gets completed, work is queued to issue the deferred qc. 4) Timeout or error happens, ap->deferred_qc is cleared. The queued work is currently NOT canceled. 5) Port is reset. 6) One or several NCQ commands are queued. 7) A non-NCQ command is queued, gets stored in ap->deferred_qc. 8) Work is finally run. Yet at this time, there is still NCQ commands in flight. The work in 8) really belongs to the non-NCQ command in 2), not to the non-NCQ command in 7). The reason why the work is executed when it is not supposed to, is because it was never canceled when ap->deferred_qc was cleared in 4). Thus, ensure that we always cancel the work after clearing ap->deferred_qc. Another potential fix would have been to let ata_scsi_deferred_qc_work() do nothing if ap->ops->qc_defer() returns non-zero. However, canceling the work when clearing ap->deferred_qc seems slightly more logical, as we hold the ap->lock when clearing ap->deferred_qc, so we know that the work cannot be holding the lock. (The function could be waiting for the lock, but that is okay since it will do nothing if ap->deferred_qc is not set.) Reported-by: syzbot+bcaf842a1e8ead8dfb89@syzkaller.appspotmail.com Fixes: 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation") Fixes: eddb98ad9364 ("ata: libata-eh: correctly handle deferred qc timeouts") Reviewed-by: Igor Pylypiv Reviewed-by: Damien Le Moal Signed-off-by: Niklas Cassel Signed-off-by: Greg Kroah-Hartman

ata: libata: avoid long timeouts on hot-unplugged SATA DAS

2026-03-04T12:20:28Z

[ Upstream commit 151cabd140322205e27dae5c4bbf261ede0056e3 ] When a SATA DAS enclosure is connected behind a Thunderbolt PCIe switch, hot-unplugging the whole enclosure causes pciehp to tear down the PCI hierarchy before the SCSI layer issues SYNCHRONIZE CACHE and START STOP UNIT for the disks. libata still queues these commands and the AHCI driver tries to access the HBA registers even though the PCI channel is already offline. This results in a series of timeouts and error recovery attempts, e.g.: [ 824.778346] pcieport 0000:00:07.0: pciehp: Slot(14): Link Down [ 891.612720] ata8.00: qc timeout after 5000 msecs (cmd 0xec) [ 902.876501] ata8.00: qc timeout after 10000 msecs (cmd 0xec) [ 934.107998] ata8.00: qc timeout after 30000 msecs (cmd 0xec) [ 936.206431] sd 7:0:0:0: [sda] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK ... [ 1006.298356] ata1.00: qc timeout after 5000 msecs (cmd 0xec) [ 1017.561926] ata1.00: qc timeout after 10000 msecs (cmd 0xec) [ 1048.791790] ata1.00: qc timeout after 30000 msecs (cmd 0xec) [ 1050.890035] sd 0:0:0:0: [sdb] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK With this patch applied, the same hot-unplug looks like: [ 59.965496] pcieport 0000:00:07.0: pciehp: Slot(14): Link Down [ 60.002502] sd 7:0:0:0: [sda] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK ... [ 60.103050] sd 0:0:0:0: [sdb] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK In this test setup with two disks, the hot-unplug sequence shrinks from about 226 seconds (~3.8 minutes) between the Link Down event and the last SYNCHRONIZE CACHE failure to under a second. Without this patch the total delay grows roughly with the number of disks, because each disk gets its own SYNCHRONIZE CACHE and qc timeout series. If the underlying PCI device is already gone, these commands cannot succeed anyway. Avoid issuing them by introducing ata_adapter_is_online(), which checks pci_channel_offline() for PCI-based hosts. It is used from ata_scsi_find_dev() to return NULL, causing the SCSI layer to fail new commands with DID_BAD_TARGET immediately, and from ata_qc_issue() to bail out before touching the HBA registers. Since such failures would otherwise trigger libata error handling, ata_adapter_is_online() is also consulted from ata_scsi_port_error_handler(). When the adapter is offline, libata skips ap->ops->error_handler(ap) and completes error handling using the existing path, rather than running a full EH sequence against a dead adapter. With this change, SYNCHRONIZE CACHE and START STOP UNIT commands issued during hot-unplug fail quickly once the PCI channel is offline, without qc timeout spam or long libata EH delays. Suggested-by: Damien Le Moal Signed-off-by: Henry Tseng Signed-off-by: Damien Le Moal Signed-off-by: Sasha Levin

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

2026-02-26T22:59:46Z

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-scsi: refactor ata_scsi_translate()

2026-02-26T22:59:46Z

commit bb3a8154b1a1dc2c86d037482c0a2cf9186829ed upstream. Factor out of ata_scsi_translate() the code handling queued command deferral using the port qc_defer callback and issuing the queued command with ata_qc_issue() into the new function ata_scsi_qc_issue(), and simplify the goto used in ata_scsi_translate(). While at it, also add a lockdep annotation to check that the port lock is held when ata_scsi_translate() is called. No functional changes. Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Martin K. Petersen Reviewed-by: John Garry Reviewed-by: Igor Pylypiv Signed-off-by: Greg Kroah-Hartman

ata: libata-scsi: Fix system suspend for a security locked drive

2025-11-20T12:37:17Z

Commit cf3fc037623c ("ata: libata-scsi: Fix ata_to_sense_error() status handling") fixed ata_to_sense_error() to properly generate sense key ABORTED COMMAND (without any additional sense code), instead of the previous bogus sense key ILLEGAL REQUEST with the additional sense code UNALIGNED WRITE COMMAND, for a failed command. However, this broke suspend for Security locked drives (drives that have Security enabled, and have not been Security unlocked by boot firmware). The reason for this is that the SCSI disk driver, for the Synchronize Cache command only, treats any sense data with sense key ILLEGAL REQUEST as a successful command (regardless of ASC / ASCQ). After commit cf3fc037623c ("ata: libata-scsi: Fix ata_to_sense_error() status handling") the code that treats any sense data with sense key ILLEGAL REQUEST as a successful command is no longer applicable, so the command fails, which causes the system suspend to be aborted: sd 1:0:0:0: PM: dpm_run_callback(): scsi_bus_suspend returns -5 sd 1:0:0:0: PM: failed to suspend async: error -5 PM: Some devices failed to suspend, or early wake event detected To make suspend work once again, for a Security locked device only, return sense data LOGICAL UNIT ACCESS NOT AUTHORIZED, the actual sense data which a real SCSI device would have returned if locked. The SCSI disk driver treats this sense data as a successful command. Cc: stable@vger.kernel.org Reported-by: Ilia Baryshnikov Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220704 Fixes: cf3fc037623c ("ata: libata-scsi: Fix ata_to_sense_error() status handling") Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen Reviewed-by: Damien Le Moal Signed-off-by: Niklas Cassel

ata: libata-scsi: Add missing scsi_device_put() in ata_scsi_dev_rescan()

2025-11-20T12:12:26Z

Call scsi_device_put() in ata_scsi_dev_rescan() if the device or its queue are not running. Fixes: 0c76106cb975 ("scsi: sd: Fix TCG OPAL unlock on system resume") Cc: stable@vger.kernel.org Signed-off-by: Yihang Li Reviewed-by: Damien Le Moal Signed-off-by: Niklas Cassel

Merge tag 'pull-getgeo' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs into for-6.18/block

2025-09-03T21:15:43Z

Pull struct block_device getgeo changes from Al. "switching ->getgeo() from struct block_device to struct gendisk Signed-off-by: Al Viro " * tag 'pull-getgeo' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: block: switch ->getgeo() to struct gendisk scsi: switch ->bios_param() to passing gendisk scsi: switch scsi_bios_ptable() and scsi_partsize() to gendisk

ata: libata-scsi: Fix CDL control

2025-08-14T09:58:12Z

Delete extra checks for the ATA_DFLAG_CDL_ENABLED flag that prevent SET FEATURES command from being issued to a drive when NCQ commands are active. ata_mselect_control_ata_feature() sets / clears the ATA_DFLAG_CDL_ENABLED flag during the translation of MODE SELECT to SET FEATURES. If SET FEATURES gets deferred due to outstanding NCQ commands, the original MODE SELECT command will be re-queued. When the re-queued MODE SELECT goes through the ata_mselect_control_ata_feature() translation again, SET FEATURES will not be issued because ATA_DFLAG_CDL_ENABLED has been already set or cleared by the initial translation of MODE SELECT. The ATA_DFLAG_CDL_ENABLED checks in ata_mselect_control_ata_feature() are safe to remove because scsi_cdl_enable() implements a similar logic that avoids enabling CDL if it has been enabled already. Fixes: 17e897a45675 ("ata: libata-scsi: Improve CDL control") Cc: stable@vger.kernel.org Signed-off-by: Igor Pylypiv Reviewed-by: Niklas Cassel Signed-off-by: Damien Le Moal

scsi: switch ->bios_param() to passing gendisk

2025-08-13T06:59:28Z

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-scsi: Return aborted command when missing sense and result TF

2025-07-31T03:56:11Z

ata_gen_ata_sense() is always called for a failed qc missing sense data so that a sense key, code and code qualifier can be generated using ata_to_sense_error() from the qc status and error fields of its result task file. However, if the qc does not have its result task file filled, ata_gen_ata_sense() returns early without setting a sense key. Improve this by defaulting to returning ABORTED COMMAND without any additional sense code, since we do not know the reason for the failure. The same fix is also applied in ata_gen_passthru_sense() with the additional check that the qc failed (qc->err_mask is set). Fixes: 816be86c7993 ("ata: libata-scsi: Check ATA_QCFLAG_RTF_FILLED before using result_tf") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen