linux.git/drivers/ata/libata.h, branch v7.2-rc2

ata: libata-core: Reject an invalid concurrent positioning ranges count

2026-07-03T04:44:18+00:00

ata_dev_config_cpr() takes the number of range descriptors from buf[0]
of the concurrent positioning ranges log (up to 255), which the device
reports independently of the log size in the GPL directory. The count is
then walked at a fixed 32-byte stride in two places with no bound: the
log read here, and the INQUIRY VPD page B9h emitter, which writes one
descriptor per range into the fixed 2048-byte ata_scsi_rbuf. A device
reporting a count larger than its own log overflows the read buffer (up
to 7704 bytes past a 512-byte slab), and a count above 62 overflows the
response buffer on the emit side.

Bound the count once, on probe, against both the log the device returned
and the number of descriptors the VPD B9h response buffer can hold
(ATA_DEV_MAX_CPR, derived from the rbuf size). Reject an out-of-range
count with a warning; this keeps the emitter in bounds with no separate
change there.

Suggested-by: Damien Le Moal 
Fixes: fe22e1c2f705 ("libata: support concurrent positioning ranges log")
Fixes: c745dfc541e7 ("libata: fix reading concurrent positioning ranges log")
Cc: stable@vger.kernel.org
Signed-off-by: Bryam Vargas 
Reviewed-by: Niklas Cassel 
Signed-off-by: Damien Le Moal

ata: Annotate functions in the issuing path with __must_hold()

2026-06-01T17:14:41+00:00

Annotate the following functions used in the issuing path:
ata_qc_issue(), ata_sas_queuecmd(), ata_scsi_qc_issue(),
ata_scsi_translate(), __ata_scsi_queuecmd()

These functions are all used in the issuing path, so context analysis will
be able to verify that the ap lock is held, from it is taken in
sas_queuecommand() or ata_scsi_queuecmd() all the way down to
ata_qc_issue().

Commenting out the spin_lock_irqsave() successfully results in a compiler
error on Clang 23.

Signed-off-by: Bart Van Assche 
Co-developed-by: Niklas Cassel 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Niklas Cassel

ata: libata: Pass ap parameter directly to functions in the issuing path

2026-06-01T17:14:29+00:00

Context analysis cannot recognize that qc->ap == ap.

Therefore, grow a struct ata_port parameter to the following functions:
ata_qc_issue(), __ata_scsi_queuecmd(), and ata_scsi_translate()
such that we will be able to enable context analysis in a follow-up commit.

No functionality has been changed.

Signed-off-by: Bart Van Assche 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Niklas Cassel

ata: libata: Document when host->eh_mutex should be held

2026-06-01T17:09:08+00:00

Annotate the following functions with __must_hold(&host->eh_mutex):
 * All ata_port_operations.error_handler() implementations.
 * ata_eh_reset() and ata_eh_recover() because these functions call
   ata_eh_release() and ata_eh_acquire().
 * All callers of ata_eh_reset() and ata_eh_recover().

Enable Clang's context analysis. This will cause the build to fail if
e.g. a locking bug would be introduced in an error path. This patch
should not affect the generated assembler code.

Signed-off-by: Bart Van Assche 
[cassel: drop note about clang 23 from commit log]
Signed-off-by: Niklas Cassel

ata: libata: Add an argument to ata_eh_reset()

2026-06-01T17:09:07+00:00

Pass the ATA port pointer as first argument to ata_eh_reset(). No
functionality has been changed. This patch prepares for enabling lock
context analysis. Without this patch, lockdep_assert_held() statements
would have to be added before each ata_eh_reset() call because the
compiler doesn't know that ap->link.p == ap. See also ata_link_init().

Signed-off-by: Bart Van Assche 
Signed-off-by: Niklas Cassel

Merge tag 'ata-6.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux

2026-02-13T01:12:43+00:00

Pull ATA updates from Damien Le Moal:

 - Cleanup IRQ masking in the handling of completed report zones
   commands (Niklas)

 - Improve the handling of Thunderbolt attached devices to speed up
   device removal (Henry)

 - Several patches to generalize the existing max_sec quirks to
   facilitates quirking the maximum command size of buggy drives, many
   of which have recently showed up with the recent increase of the
   default max_sectors block limit (Niklas)

 - Cleanup the ahci-platform and sata dt-bindings schema (Rob,
   Manivannan)

 - Improve device node scan in the ahci-dwc driver (Krzysztof)

 - Remove clang W=1 warnings with the ahci-imx and ahci-xgene drivers
   (Krzysztof)

 - Fix a long standing potential command starvation situation with
   non-NCQ commands issued when NCQ commands are on-going (me)

 - Limit max_sectors to 8191 on the INTEL SSDSC2KG480G8 SSD (Niklas)

 - Remove Vesa Local Bus (VLB) support in the pata_legacy driver (Ethan)

 - Simple fixes in the pata_cypress (typo) and pata_ftide010 (timing)
   drivers (Ethan, Linus W)

* tag 'ata-6.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux:
  ata: pata_ftide010: Fix some DMA timings
  ata: pata_cypress: fix typo in error message
  ata: pata_legacy: remove VLB support
  ata: libata-core: Quirk INTEL SSDSC2KG480G8 max_sectors
  dt-bindings: ata: sata: Document the graph port
  ata: libata-scsi: avoid Non-NCQ command starvation
  ata: libata-scsi: refactor ata_scsi_translate()
  ata: ahci-xgene: Fix Wvoid-pointer-to-enum-cast warning
  ata: ahci-imx: Fix Wvoid-pointer-to-enum-cast warning
  ata: ahci-dwc: Simplify with scoped for each OF child loop
  dt-bindings: ata: ahci-platform: Drop unnecessary select schema
  ata: libata: Allow more quirks
  ata: libata: Add libata.force parameter max_sec
  ata: libata: Add support to parse equal sign in libata.force
  ata: libata: Change libata.force to use the generic ATA_QUIRK_MAX_SEC quirk
  ata: libata: Add ata_force_get_fe_for_dev() helper
  ata: libata: Add ATA_QUIRK_MAX_SEC and convert all device quirks
  ata: libata: avoid long timeouts on hot-unplugged SATA DAS
  ata: libata-scsi: Remove superfluous local_irq_save()

scsi: Change the return type of the .queuecommand() callback

2026-01-24T02:32:34+00:00

In clang version 21.1 and later the -Wimplicit-enum-enum-cast warning
option has been introduced. This warning is enabled by default and can
be used to catch .queuecommand() implementations that return another
value than 0 or one of the SCSI_MLQUEUE_* constants. Hence this patch
that changes the return type of the .queuecommand() implementations from
'int' into 'enum scsi_qc_status'. No functionality has been changed.

Cc: Damien Le Moal 
Cc: John Garry 
Signed-off-by: Bart Van Assche 
Link: https://patch.msgid.link/20260115210357.2501991-6-bvanassche@acm.org
Signed-off-by: Martin K. Petersen

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

2026-01-14T10:07:14+00:00

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

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

2025-12-15T07:32:05+00:00

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

scsi: ata: Stop disk on restart if ACPI power resources are found

2025-11-08T18:24:56+00:00

Some embedded devices have the ability to control whether power is
provided to the disks via the SATA power connector or not. ACPI power
resources are usually off by default, thus making it unclear if the
specific power resource will retain its state after a restart. If power
resources are defined on ATA ports / devices in ACPI, we should stop the
disk on SYSTEM_RESTART, to ensure the disk will not lose power while
active.

Add a new function, ata_acpi_dev_manage_restart(), that will be used to
determine if a disk should be stopped before restarting the system. If a
usable ACPI power resource has been found, it is assumed that the disk
will lose power after a restart and should be stopped to avoid unclean
shutdown due to power loss.

Reviewed-by: Damien Le Moal 
Signed-off-by: Markus Probst 
Link: https://patch.msgid.link/20251104142413.322347-4-markus.probst@posteo.de
Signed-off-by: Martin K. Petersen