linux-toradex.git/drivers/ata/libata-eh.c, branch v6.11-rc5

scsi: sd: Fix TCG OPAL unlock on system resume

2024-03-25T19:46:12+00:00

Commit 3cc2ffe5c16d ("scsi: sd: Differentiate system and runtime start/stop
management") introduced the manage_system_start_stop scsi_device flag to
allow libata to indicate to the SCSI disk driver that nothing should be
done when resuming a disk on system resume. This change turned the
execution of sd_resume() into a no-op for ATA devices on system
resume. While this solved deadlock issues during device resume, this change
also wrongly removed the execution of opal_unlock_from_suspend().  As a
result, devices with TCG OPAL locking enabled remain locked and
inaccessible after a system resume from sleep.

To fix this issue, introduce the SCSI driver resume method and implement it
with the sd_resume() function calling opal_unlock_from_suspend(). The
former sd_resume() function is renamed to sd_resume_common() and modified
to call the new sd_resume() function. For non-ATA devices, this result in
no functional changes.

In order for libata to explicitly execute sd_resume() when a device is
resumed during system restart, the function scsi_resume_device() is
introduced. libata calls this function from the revalidation work executed
on devie resume, a state that is indicated with the new device flag
ATA_DFLAG_RESUMING. Doing so, locked TCG OPAL enabled devices are unlocked
on resume, allowing normal operation.

Fixes: 3cc2ffe5c16d ("scsi: sd: Differentiate system and runtime start/stop management")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218538
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20240319071209.1179257-1-dlemoal@kernel.org
Signed-off-by: Martin K. Petersen

ata: libata-eh: Spinup disk on resume after revalidation

2023-10-13T03:46:03+00:00

Move the call to ata_dev_power_set_active() to transition a disk in
standby power mode to the active power mode from
ata_eh_revalidate_and_attach() before doing revalidation to the end of
ata_eh_recover(), after the link speed for the device is reconfigured
(if that was necessary). This is safer as this ensure that the VERIFY
command executed to spinup the disk is executed with the drive properly
reconfigured first.

Signed-off-by: Damien Le Moal 
Reviewed-by: Niklas Cassel 
Tested-by: Geert Uytterhoeven

ata: libata-eh: Reduce "disable device" message verbosity

2023-10-03T00:39:50+00:00

There is no point in warning about a device being disabled when we
expect it to be, that is, on suspend, shutdown or when detaching the
device.

Suppress the message "disable device" for these cases by introducing the
EH static function ata_eh_dev_disable() and by using it in
ata_eh_unload() and ata_eh_detach_dev(). ata_dev_disable() code is
modified to call this new function after printing the "disable device"
message.

Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Tested-by: Chia-Lin Kao (AceLan) 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Martin K. Petersen

ata: libata-eh: Improve reset error messages

2023-10-03T00:39:50+00:00

Some drives are really slow to spinup on resume, resulting is a very
slow response to COMRESET and to error messages such as:

ata1: COMRESET failed (errno=-16)
ata1: link is slow to respond, please be patient (ready=0)
ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
ata1.00: configured for UDMA/133

Given that the slowness of the response is indicated with the message
"link is slow to respond..." and that resets are retried until the
device is detected as online after up to 1min (ata_eh_reset_timeouts),
there is no point in printing the "COMRESET failed" error message. Let's
not scare the user with non fatal errors and only warn about reset
failures in ata_eh_reset() when all reset retries have been exhausted.

Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Tested-by: Chia-Lin Kao (AceLan) 
Tested-by: Geert Uytterhoeven 
Reviewed-by: Martin K. Petersen

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-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-eh: do not thaw the port twice in ata_eh_reset()

2023-09-16T12:11:28+00:00

commit 1e641060c4b5 ("libata: clear eh_info on reset completion") added
a workaround that broke the retry mechanism in ATA EH.

Tejun himself suggested to remove this workaround when it was identified
to cause additional problems:
https://lore.kernel.org/linux-ide/20110426135027.GI878@htj.dyndns.org/

He even said:
"Hmm... it seems I wasn't thinking straight when I added that work around."
https://lore.kernel.org/linux-ide/20110426155229.GM878@htj.dyndns.org/

While removing the workaround solved the issue, however, the workaround was
kept to avoid "spurious hotplug events during reset", and instead another
workaround was added on top of the existing workaround in commit
8c56cacc724c ("libata: fix unexpectedly frozen port after ata_eh_reset()").

Because these IRQs happened when the port was frozen, we know that they
were actually a side effect of PxIS and IS.IPS(x) not being cleared before
the COMRESET. This is now done in commit 94152042eaa9 ("ata: libahci: clear
pending interrupt status"), so these workarounds can now be removed.

Since commit 1e641060c4b5 ("libata: clear eh_info on reset completion") has
now been reverted, the ATA EH retry mechanism is functional again, so there
is once again no need to thaw the port more than once in ata_eh_reset().

This reverts "the workaround on top of the workaround" introduced in commit
8c56cacc724c ("libata: fix unexpectedly frozen port after ata_eh_reset()").

Signed-off-by: Niklas Cassel 
Signed-off-by: Damien Le Moal

ata: libata-eh: do not clear ATA_PFLAG_EH_PENDING in ata_eh_reset()

2023-09-16T12:10:37+00:00

ata_scsi_port_error_handler() starts off by clearing ATA_PFLAG_EH_PENDING,
before calling ap->ops->error_handler() (without holding the ap->lock).

If an error IRQ is received while ap->ops->error_handler() is running,
the irq handler will set ATA_PFLAG_EH_PENDING.

Once ap->ops->error_handler() returns, ata_scsi_port_error_handler()
checks if ATA_PFLAG_EH_PENDING is set, and if it is, another iteration
of ATA EH is performed.

The problem is that ATA_PFLAG_EH_PENDING is not only cleared by
ata_scsi_port_error_handler(), it is also cleared by ata_eh_reset().

ata_eh_reset() is called by ap->ops->error_handler(). This additional
clearing done by ata_eh_reset() breaks the whole retry logic in
ata_scsi_port_error_handler(). Thus, if an error IRQ is received while
ap->ops->error_handler() is running, the port will currently remain
frozen and will never get re-enabled.

The additional clearing in ata_eh_reset() was introduced in commit
1e641060c4b5 ("libata: clear eh_info on reset completion").

Looking at the original error report:
https://marc.info/?l=linux-ide&m=124765325828495&w=2

We can see the following happening:
[    1.074659] ata3: XXX port freeze
[    1.074700] ata3: XXX hardresetting link, stopping engine
[    1.074746] ata3: XXX flipping SControl

[    1.411471] ata3: XXX irq_stat=400040 CONN|PHY
[    1.411475] ata3: XXX port freeze

[    1.420049] ata3: XXX starting engine
[    1.420096] ata3: XXX rc=0, class=1
[    1.420142] ata3: XXX clearing IRQs for thawing
[    1.420188] ata3: XXX port thawed
[    1.420234] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)

We are not supposed to be able to receive an error IRQ while the port is
frozen (PxIE is set to 0, i.e. all IRQs for the port are disabled).

AHCI 1.3.1 section 10.7.1.1 First Tier (IS Register) states:
"Each bit location can be thought of as reporting a '1' if the virtual
"interrupt line" for that port is indicating it wishes to generate an
interrupt. That is, if a port has one or more interrupt status bit set,
and the enables for those status bits are set, then this bit shall be set."

Additionally, AHCI state P:ComInit clearly shows that the state machine
will only jump to P:ComInitSetIS (which sets IS.IPS(x) to '1'), if PxIE.PCE
is set to '1'. In our case, PxIE is set to 0, so IS.IPS(x) won't get set.

So IS.IPS(x) only gets set if PxIS and PxIE is set.

AHCI 1.3.1 section 10.7.1.1 First Tier (IS Register) also states:
"The bits in this register are read/write clear. It is set by the level of
the virtual interrupt line being a set, and cleared by a write of '1' from
the software."

So if IS.IPS(x) is set, you need to explicitly clear it by writing a 1 to
IS.IPS(x) for that port.

Since PxIE is cleared, the only way to get an interrupt while the port is
frozen, is if IS.IPS(x) is set, and the only way IS.IPS(x) can be set when
the port is frozen, is if it was set before the port was frozen.

However, since commit 737dd811a3db ("ata: libahci: clear pending interrupt
status"), we clear both PxIS and IS.IPS(x) after freezing the port, but
before the COMRESET, so the problem that commit 1e641060c4b5 ("libata:
clear eh_info on reset completion") fixed can no longer happen.

Thus, revert commit 1e641060c4b5 ("libata: clear eh_info on reset
completion"), so that the retry logic in ata_scsi_port_error_handler()
works once again. (The retry logic is still needed, since we can still
get an error IRQ _after_ the port has been thawed, but before
ata_scsi_port_error_handler() takes the ap->lock in order to check
if ATA_PFLAG_EH_PENDING is set.)

Signed-off-by: Niklas Cassel 
Signed-off-by: Damien Le Moal

ata: libata: remove references to non-existing error_handler()

2023-08-02T08:45:10+00:00

With commit 65a15d6560df ("scsi: ipr: Remove SATA support") all
libata drivers now have the error_handler() callback provided,
so we can stop checking for non-existing error_handler callback.

Signed-off-by: Hannes Reinecke 
[niklas: fixed review comments, rebased, solved conflicts during rebase,
fixed bug that unconditionally dumped all QCs, removed the now unused
function ata_dump_status(), removed the now unreachable failure paths in
atapi_qc_complete(), removed the non-EH function to request ATAPI sense]
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: libata-eh: fix reset timeout type

2023-08-02T08:37:06+00:00

ata_eh_reset_timeouts[] stores 'unsigned long' timeouts in ms, while
ata_eh_reset() passes these values to ata_deadline() that takes just
'unsigned int timeout_msecs' parameter.  Change the reset timeout table
element's type to 'unsigned int' -- all timeouts fit into 'unsigned int'
but we have to change ULONG_MAX to UINT_MAX...

Signed-off-by: Sergey Shtylyov 
Signed-off-by: Damien Le Moal