linux.git/drivers/ata, branch v6.6-rc4

Merge tag 'ata-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata

2023-09-29T20:38:34+00:00

Pull ATA fixes from Damien Le Moal:
 "A larger than usual set of fixes for 6.6-rc4 due to the unexpected
  number of fixes needed to address ATA disks suspend/resume issues.

  In more detail:

   - Add missing additionalProperties on child nodes to the pata-common
     DT bindings (Rob)

   - Fix handling of the REPORT SUPPORTED OPERATION CODES command to
     ignore reserved bits (Niklas)

   - Increase port multiplier soft reset timeout to accomodate slow
     devices and avoid issues on wakeup (Matthias)

   - A couple of minor code fixes to avoid compilation warnings in
     libata-core and libata-eh (me)

   - Many patches from me to address suspend/resume issues, and in
     particular a potential deadlock on resume due to the SCSI disk
     driver resume operation not being synchronized with libata EH port
     resume handling.

     This is addressed by changing the scsi disk driver disk start/stop
     control to allow libata to execute disk suspend (spin down) and
     resume (spin up) on its own during system suspend/resume. Runtime
     suspend/resume control remains with the SCSI disk driver.

     Other fixes include:
      - Fix libata power management request issuing to avoid races
      - Establish a link between ATA ports and SCSI devices to order PM
        operations
      - Fix device removal to avoid issues with driver rmmod removal
      - Fix synchronization of libata device rescan and SCSI disk resume
        operation
      - Remove libsas PM operations as suspend/resume is handled
        directly by the sas controller resume
      - Fix the SCSI disk driver to not issue commands to suspended
        disks, thus avoiding potential system lock-up on resume"

* tag 'ata-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata:
  ata: libata-eh: Fix compilation warning in ata_eh_link_report()
  ata: libata-core: Fix compilation warning in ata_dev_config_ncq()
  scsi: sd: Do not issue commands to suspended disks on shutdown
  ata: libata-core: Do not register PM operations for SAS ports
  ata: libata-scsi: Fix delayed scsi_rescan_device() execution
  scsi: Do not attempt to rescan suspended devices
  ata: libata-scsi: Disable scsi device manage_system_start_stop
  scsi: sd: Differentiate system and runtime start/stop management
  ata: libata-scsi: link ata port and scsi device
  ata: libata-core: Fix port and device removal
  ata: libata-core: Fix ata_port_request_pm() locking
  ata: libata-sata: increase PMP SRST timeout to 10s
  ata: libata-scsi: ignore reserved bits for REPORT SUPPORTED OPERATION CODES
  dt-bindings: ata: pata-common: Add missing additionalProperties on child nodes

ata: libata-eh: Fix compilation warning in ata_eh_link_report()

2023-09-28T12:24:18+00:00

The 6 bytes length of the tries_buf string in ata_eh_link_report() is
too short and results in a gcc compilation warning with W-!:

drivers/ata/libata-eh.c: In function ‘ata_eh_link_report’:
drivers/ata/libata-eh.c:2371:59: warning: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 4 [-Wformat-truncation=]
 2371 |                 snprintf(tries_buf, sizeof(tries_buf), " t%d",
      |                                                           ^~
drivers/ata/libata-eh.c:2371:56: note: directive argument in the range [-2147483648, 4]
 2371 |                 snprintf(tries_buf, sizeof(tries_buf), " t%d",
      |                                                        ^~~~~~
drivers/ata/libata-eh.c:2371:17: note: ‘snprintf’ output between 4 and 14 bytes into a destination of size 6
 2371 |                 snprintf(tries_buf, sizeof(tries_buf), " t%d",
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 2372 |                          ap->eh_tries);
      |                          ~~~~~~~~~~~~~

Avoid this warning by increasing the string size to 16B.

Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Martin K. Petersen

ata: libata-core: Fix compilation warning in ata_dev_config_ncq()

2023-09-28T12:24:10+00:00

The 24 bytes length allocated to the ncq_desc string in
ata_dev_config_lba() for ata_dev_config_ncq() to use is too short,
causing the following gcc compilation warnings when compiling with W=1:

drivers/ata/libata-core.c: In function ‘ata_dev_configure’:
drivers/ata/libata-core.c:2378:56: warning: ‘%d’ directive output may be truncated writing between 1 and 2 bytes into a region of size between 1 and 11 [-Wformat-truncation=]
 2378 |                 snprintf(desc, desc_sz, "NCQ (depth %d/%d)%s", hdepth,
      |                                                        ^~
In function ‘ata_dev_config_ncq’,
    inlined from ‘ata_dev_config_lba’ at drivers/ata/libata-core.c:2649:8,
    inlined from ‘ata_dev_configure’ at drivers/ata/libata-core.c:2952:9:
drivers/ata/libata-core.c:2378:41: note: directive argument in the range [1, 32]
 2378 |                 snprintf(desc, desc_sz, "NCQ (depth %d/%d)%s", hdepth,
      |                                         ^~~~~~~~~~~~~~~~~~~~~
drivers/ata/libata-core.c:2378:17: note: ‘snprintf’ output between 16 and 31 bytes into a destination of size 24
 2378 |                 snprintf(desc, desc_sz, "NCQ (depth %d/%d)%s", hdepth,
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 2379 |                         ddepth, aa_desc);
      |                         ~~~~~~~~~~~~~~~~

Avoid these warnings and the potential truncation by changing the size
of the ncq_desc string to 32 characters.

Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Martin K. Petersen

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: Fix delayed scsi_rescan_device() execution

2023-09-28T12:23:10+00:00

Commit 6aa0365a3c85 ("ata: libata-scsi: Avoid deadlock on rescan after
device resume") modified ata_scsi_dev_rescan() to check the scsi device
"is_suspended" power field to ensure that the scsi device associated
with an ATA device is fully resumed when scsi_rescan_device() is
executed. However, this fix is problematic as:
1) It relies on a PM internal field that should not be used without PM
   device locking protection.
2) The check for is_suspended and the call to scsi_rescan_device() are
   not atomic and a suspend PM event may be triggered between them,
   casuing scsi_rescan_device() to be called on a suspended device and
   in that function blocking while holding the scsi device lock. This
   would deadlock a following resume operation.
These problems can trigger PM deadlocks on resume, especially with
resume operations triggered quickly after or during suspend operations.
E.g., a simple bash script like:

for (( i=0; i<10; i++ )); do
	echo "+2 > /sys/class/rtc/rtc0/wakealarm
	echo mem > /sys/power/state
done

that triggers a resume 2 seconds after starting suspending a system can
quickly lead to a PM deadlock preventing the system from correctly
resuming.

Fix this by replacing the check on is_suspended with a check on the
return value given by scsi_rescan_device() as that function will fail if
called against a suspended device. Also make sure rescan tasks already
scheduled are first cancelled before suspending an ata port.

Fixes: 6aa0365a3c85 ("ata: libata-scsi: Avoid deadlock on rescan after device resume")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Niklas Cassel 
Tested-by: Geert Uytterhoeven 
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

scsi: sd: Differentiate system and runtime start/stop management

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

The underlying device and driver of a SCSI disk may have different
system and runtime power mode control requirements. This is because
runtime power management affects only the SCSI disk, while system level
power management affects all devices, including the controller for the
SCSI disk.

For instance, issuing a START STOP UNIT command when a SCSI disk is
runtime suspended and resumed is fine: the command is translated to a
STANDBY IMMEDIATE command to spin down the ATA disk and to a VERIFY
command to wake it up. The SCSI disk runtime operations have no effect
on the ata port device used to connect the ATA disk. However, for
system suspend/resume operations, the ATA port used to connect the
device will also be suspended and resumed, with the resume operation
requiring re-validating the device link and the device itself. In this
case, issuing a VERIFY command to spinup the disk must be done before
starting to revalidate the device, when the ata port is being resumed.
In such case, we must not allow the SCSI disk driver to issue START STOP
UNIT commands.

Allow a low level driver to refine the SCSI disk start/stop management
by differentiating system and runtime cases with two new SCSI device
flags: manage_system_start_stop and manage_runtime_start_stop. These new
flags replace the current manage_start_stop flag. Drivers setting the
manage_start_stop are modifed to set both new flags, thus preserving the
existing start/stop management behavior. For backward compatibility, the
old manage_start_stop sysfs device attribute is kept as a read-only
attribute showing a value of 1 for devices enabling both new flags and 0
otherwise.

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-scsi: link ata port and scsi device

2023-09-28T12:22:57+00:00

There is no direct device ancestry defined between an ata_device and
its scsi device which prevents the power management code from correctly
ordering suspend and resume operations. Create such ancestry with the
ata device as the parent to ensure that the scsi device (child) is
suspended before the ata device and that resume handles the ata device
before the scsi device.

The parent-child (supplier-consumer) relationship is established between
the ata_port (parent) and the scsi device (child) with the function
device_add_link(). The parent used is not the ata_device as the PM
operations are defined per port and the status of all devices connected
through that port is controlled from the port operations.

The device link is established with the new function
ata_scsi_slave_alloc(), and this function is used to define the
->slave_alloc callback of the scsi host template of all ata drivers.

Fixes: a19a93e4c6a9 ("scsi: core: pm: Rely on the device driver core for async power management")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Niklas Cassel 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Martin K. Petersen 
Reviewed-by: John Garry

ata: libata-core: Fix port and device removal

2023-09-28T12:22:53+00:00

Whenever an ATA adapter driver is removed (e.g. rmmod),
ata_port_detach() is called repeatedly for all the adapter ports to
remove (unload) the devices attached to the port and delete the port
device itself. Removing of devices is done using libata EH with the
ATA_PFLAG_UNLOADING port flag set. This causes libata EH to execute
ata_eh_unload() which disables all devices attached to the port.

ata_port_detach() finishes by calling scsi_remove_host() to remove the
scsi host associated with the port. This function will trigger the
removal of all scsi devices attached to the host and in the case of
disks, calls to sd_shutdown() which will flush the device write cache
and stop the device. However, given that the devices were already
disabled by ata_eh_unload(), the synchronize write cache command and
start stop unit commands fail. E.g. running "rmmod ahci" with first
removing sd_mod results in error messages like:

ata13.00: disable device
sd 0:0:0:0: [sda] Synchronizing SCSI cache
sd 0:0:0:0: [sda] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
sd 0:0:0:0: [sda] Stopping disk
sd 0:0:0:0: [sda] Start/Stop Unit failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK

Fix this by removing all scsi devices of the ata devices connected to
the port before scheduling libata EH to disable the ATA devices.

Fixes: 720ba12620ee ("[PATCH] libata-hp: update unload-unplug")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Niklas Cassel 
Tested-by: Chia-Lin Kao (AceLan) 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Martin K. Petersen

ata: libata-core: Fix ata_port_request_pm() locking

2023-09-28T12:22:50+00:00

The function ata_port_request_pm() checks the port flag
ATA_PFLAG_PM_PENDING and calls ata_port_wait_eh() if this flag is set to
ensure that power management operations for a port are not scheduled
simultaneously. However, this flag check is done without holding the
port lock.

Fix this by taking the port lock on entry to the function and checking
the flag under this lock. The lock is released and re-taken if
ata_port_wait_eh() needs to be called. The two WARN_ON() macros checking
that the ATA_PFLAG_PM_PENDING flag was cleared are removed as the first
call is racy and the second one done without holding the port lock.

Fixes: 5ef41082912b ("ata: add ata port system PM callbacks")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Tested-by: Chia-Lin Kao (AceLan) 
Reviewed-by: Niklas Cassel 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Bart Van Assche