kernel/linux.git/drivers/ata/libata.h, branch v6.6.132

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

2026-03-04T12:20:50+00:00

[ 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-core: Do not register PM operations for SAS ports

2023-09-28T12:23:14+00:00

libsas does its own domain based power management of ports. For such ports, libata should not use a device type defining power management operations as executing these operations for suspend/resume in addition to libsas calls to ata_sas_port_suspend() and ata_sas_port_resume() is not necessary (and likely dangerous to do, even though problems are not seen currently). Introduce the new ata_port_sas_type device_type for ports managed by libsas. This new device type is used in ata_tport_add() and is defined without power management operations. Fixes: 2fcbdcb4c802 ("[SCSI] libata: export ata_port suspend/resume infrastructure for sas") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Tested-by: Chia-Lin Kao (AceLan) Tested-by: Geert Uytterhoeven Reviewed-by: John Garry Reviewed-by: Martin K. Petersen

ata: libata-scsi: Disable scsi device manage_system_start_stop

2023-09-28T12:23:03+00:00

The introduction of a device link to create a consumer/supplier relationship between the scsi device of an ATA device and the ATA port of that ATA device fixes the ordering of system suspend and resume operations. For suspend, the scsi device is suspended first and the ata port after it. This is fine as this allows the synchronize cache and START STOP UNIT commands issued by the scsi disk driver to be executed before the ata port is disabled. For resume operations, the ata port is resumed first, followed by the scsi device. This allows having the request queue of the scsi device to be unfrozen after the ata port resume is scheduled in EH, thus avoiding to see new requests prematurely issued to the ATA device. Since libata sets manage_system_start_stop to 1, the scsi disk resume operation also results in issuing a START STOP UNIT command to the device being resumed so that the device exits standby power mode. However, restoring the ATA device to the active power mode must be synchronized with libata EH processing of the port resume operation to avoid either 1) seeing the start stop unit command being received too early when the port is not yet resumed and ready to accept commands, or after the port resume process issues commands such as IDENTIFY to revalidate the device. In this last case, the risk is that the device revalidation fails with timeout errors as the drive is still spun down. Commit 0a8589055936 ("ata,scsi: do not issue START STOP UNIT on resume") disabled issuing the START STOP UNIT command to avoid issues with it. But this is incorrect as transitioning a device to the active power mode from the standby power mode set on suspend requires a media access command. The IDENTIFY, READ LOG and SET FEATURES commands executed in libata EH context triggered by the ata port resume operation may thus fail. Fix these synchronization issues is by handling a device power mode transitions for system suspend and resume directly in libata EH context, without relying on the scsi disk driver management triggered with the manage_system_start_stop flag. To do this, the following libata helper functions are introduced: 1) ata_dev_power_set_standby(): This function issues a STANDBY IMMEDIATE command to transitiom a device to the standby power mode. For HDDs, this spins down the disks. This function applies only to ATA and ZAC devices and does nothing otherwise. This function also does nothing for devices that have the ATA_FLAG_NO_POWEROFF_SPINDOWN or ATA_FLAG_NO_HIBERNATE_SPINDOWN flag set. For suspend, call ata_dev_power_set_standby() in ata_eh_handle_port_suspend() before the port is disabled and frozen. ata_eh_unload() is also modified to transition all enabled devices to the standby power mode when the system is shutdown or devices removed. 2) ata_dev_power_set_active() and This function applies to ATA or ZAC devices and issues a VERIFY command for 1 sector at LBA 0 to transition the device to the active power mode. For HDDs, since this function will complete only once the disk spin up. Its execution uses the same timeouts as for reset, to give the drive enough time to complete spinup without triggering a command timeout. For resume, call ata_dev_power_set_active() in ata_eh_revalidate_and_attach() after the port has been enabled and before any other command is issued to the device. With these changes, the manage_system_start_stop and no_start_on_resume scsi device flags do not need to be set in ata_scsi_dev_config(). The flag manage_runtime_start_stop is still set to allow the sd driver to spinup/spindown a disk through the sd runtime operations. Fixes: 0a8589055936 ("ata,scsi: do not issue START STOP UNIT on resume") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Tested-by: Geert Uytterhoeven Reviewed-by: Martin K. Petersen

ata: libata-core: remove ata_bus_probe()

2023-08-02T08:45:36+00:00

Remove ata_bus_probe() as it is unused. Also, remove references to ata_bus_probe and port_disable in Documentation/driver-api/libata.rst, as neither exist anymore. Signed-off-by: Niklas Cassel Reviewed-by: John Garry Reviewed-by: Jason Yan Reviewed-by: Martin K. Petersen Signed-off-by: Damien Le Moal

ata,scsi: cleanup __ata_port_probe()

2023-08-02T08:45:27+00:00

Rename __ata_port_probe() to ata_port_probe() and drop the wrapper ata_sas_async_probe(). Signed-off-by: Hannes Reinecke Signed-off-by: Niklas Cassel Reviewed-by: Jason Yan Reviewed-by: John Garry Reviewed-by: Martin K. Petersen Signed-off-by: Damien Le Moal

scsi: ata: libata: Set read/write commands CDL index

2023-05-22T21:05:20+00:00

For devices supporting the command duration limits feature, translate the dld field of read and write operation to set the command duration limit index field of the command task file when the duration limit feature is enabled. The function ata_set_tf_cdl() is introduced to do this. For unqueued (non NCQ) read and write operations, this function sets the command duration limit index set as the lower 3 bits of the feature field. For queued NCQ read/write commands, the index is set as the lower 3 bits of the auxiliary field. The flag ATA_QCFLAG_HAS_CDL is introduced to indicate that a command taskfile has a non zero cdl field. Signed-off-by: Damien Le Moal Reviewed-by: Igor Pylypiv Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Co-developed-by: Niklas Cassel Signed-off-by: Niklas Cassel Link: https://lore.kernel.org/r/20230511011356.227789-19-nks@flawful.org Signed-off-by: Martin K. Petersen

scsi: ata: Declare SCSI host templates const

2023-03-24T23:19:19+00:00

Make it explicit that ATA host templates are not modified. Reviewed-by: Linus Walleij Acked-by: Damien Le Moal Reviewed-by: Serge Semin (for DWC AHCI SATA) Reviewed-by: John Garry Reviewed-by: Jon Hunter (for Tegra) Cc: Christoph Hellwig Cc: Ming Lei Cc: Hannes Reinecke Cc: John Garry Cc: Mike Christie Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20230322195515.1267197-5-bvanassche@acm.org Signed-off-by: Martin K. Petersen

ata: libata: only set sense valid flag if sense data is valid

2022-10-17T02:31:52+00:00

While this shouldn't be needed if all devices that claim that they support NCQ autosense (ata_id_has_ncq_autosense()) and/or the sense data reporting feature (ata_id_has_sense_reporting()), actually supported those features. However, there might be some old ATA devices that either have these bits set, even when they don't support those features, or they simply return malformed data when using those features. These devices should be quirked, but in order to try to minimize the impact for the users of these such devices, it was suggested by Damien Le Moal that it might be a good idea to sanity check the sense data received from the device. If the sense data looks bogus, then the sense data is never added to the scsi_cmnd command. Introduce a new function, ata_scsi_sense_is_valid(), and use it in all places where sense data is received from the device. Suggested-by: Damien Le Moal Signed-off-by: Niklas Cassel Signed-off-by: Damien Le Moal

ata: libata-core: Simplify ata_build_rw_tf()

2022-08-25T22:46:08+00:00

Since ata_build_rw_tf() is only called from ata_scsi_rw_xlat() with the tf, dev and tag arguments obtained from the queued command structure, we can simplify the interface of ata_build_rw_tf() by passing directly the qc structure as argument. Furthermore, since ata_scsi_rw_xlat() is never used for internal commands, we can also remove the internal tag check for the NCQ case. Signed-off-by: Damien Le Moal

ata: libata-core: improve parameter names for ata_dev_set_feature()

2022-08-17T16:40:42+00:00

ata_dev_set_feature() is currently used for enabling/disabling any ATA feature, e.g. SETFEATURES_SPINUP and SETFEATURE_SENSE_DATA, i.e. it is not only used to enable/disable SATA specific features. For most features, the enable/disable bit is specified in the subcommand specific field "count". It is only for the specific subcommands "Enable SATA feature" (0x10) and "Disable SATA feature" (0x90) where the field "count" is used to specify a feature instead of enable/disable. The parameter names for this function are thus quite misleading. Rename the parameter names to be more generic and in line with ACS-5, and remove the references to "SATA FEATURES" in the kernel-doc. Signed-off-by: Niklas Cassel Signed-off-by: Damien Le Moal