linux.git/drivers/scsi/sd.c, branch v3.10

Merge branch 'postmerge' into for-linus

2013-05-10T14:54:01+00:00

Signed-off-by: James Bottomley

Merge branch 'misc' into for-linus

2013-05-10T14:53:40+00:00

Signed-off-by: James Bottomley

block_device_operations->release() should return void

2013-05-07T06:16:21+00:00

The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.

Signed-off-by: Al Viro

[SCSI] sd: change to auto suspend mode

2013-05-06T19:48:31+00:00

Uses block layer runtime pm helper functions in
scsi_runtime_suspend/resume for devices that take advantage of it.

Remove scsi_autopm_* from sd open/release path and check_events path.

Signed-off-by: Lin Ming 
Signed-off-by: Aaron Lu 
Acked-by: Alan Stern 
Signed-off-by: James Bottomley

[SCSI] sd: use REQ_PM in sd's runtime suspend operation

2013-05-06T19:48:17+00:00

With the introduction of REQ_PM, modify sd's runtime suspend operation
functions to use that flag so that the operations to put the device into
runtime suspended state(i.e. sync cache and stop device) will not affect
its runtime PM status.

Signed-off-by: Lin Ming 
Signed-off-by: Aaron Lu 
Acked-by: Alan Stern 
Signed-off-by: James Bottomley

[SCSI] sd: fix array cache flushing bug causing performance problems

2013-05-02T23:15:54+00:00

Some arrays synchronize their full non volatile cache when the sd driver sends
a SYNCHRONIZE CACHE command.  Unfortunately, they can have Terrabytes of this
and we send a SYNCHRONIZE CACHE for every barrier if an array reports it has a
writeback cache.  This leads to massive slowdowns on journalled filesystems.

The fix is to allow userspace to turn off the writeback cache setting as a
temporary measure (i.e. without doing the MODE SELECT to write it back to the
device), so even though the device reported it has a writeback cache, the
user, knowing that the cache is non volatile and all they care about is
filesystem correctness, can turn that bit off in the kernel and avoid the
performance ruinous (and safety irrelevant) SYNCHRONIZE CACHE commands.

The way you do this is add a 'temporary' prefix when performing the usual
cache setting operations, so

echo temporary write through > /sys/class/scsi_disk//cache_type

Reported-by: Ric Wheeler 
Cc: 
Signed-off-by: James Bottomley

[SCSI] sd: update sd to use the new pm callbacks

2012-11-30T09:28:34+00:00

Update sd driver to use the callbacks defined in dev_pm_ops.

sd_freeze is NULL, the bus level callback has taken care of quiescing
the device so there should be nothing needs to be done here.
Consequently, sd_thaw is not needed here either.

suspend, poweroff and runtime suspend share the same routine sd_suspend,
which will sync flush and then stop the drive, this is the same as before.

resume, restore and runtime resume share the same routine sd_resume,
which will start the drive by putting it into active power state, this
is also the same as before.

Signed-off-by: Aaron Lu 
Acked-by: Alan Stern 
Acked-by: Rafael J. Wysocki 
Signed-off-by: James Bottomley

[SCSI] sd: put to stopped power state when runtime suspend

2012-11-30T09:22:09+00:00

When device is runtime suspended, put it to stopped power state to save
some power.

This will also make the behaviour consistent with what the scsi_pm.c
thinks about sd as the comment says:
sd treats runtime suspend, system suspend and system hibernate identical.
With this patch, it is now identical.
And sd_shutdown will also do nothing when it finds the device has been
runtime suspended, if we do not spin down the disk in runtime suspend
by putting it into stopped power state, the disk will be shut down
incorrectly.
And the the same problem can be solved for runtime power off after
runtime suspended case by this change.

With the current runtime scheme for disk, it will only be runtime
suspended when no process opens the disk, so this shouldn't happen a
lot, which makes it acceptable to spin down the disk when runtime
suspended. If some day a more aggressive runtime scheme is used, like
the 'request based runtime pm for disk' that Alan Stern and Lin Ming
has been working, we can introduce some policy to control this. But for
now, make it simple and correct by spinning down the disk.

Signed-off-by: Aaron Lu 
Acked-by: Alan Stern 
Acked-by: Rafael J. Wysocki 
Signed-off-by: James Bottomley

[SCSI] sd: Use SCSI read/write(16) with > 32-bit LBA drives

2012-11-27T05:00:38+00:00

Force large capacity (> 0xFFFFFFFF blocks) drives to use READ/WRITE(16) instead
of READ/WRITE(10). Some(most/all?) USB enclosures do not like READ(10) commands
when a large capacity drive is installed. This issue was reported and discussed
here: http://marc.info/?l=linux-usb&m=135247705222324

Signed-off-by: Jason J. Herne 
Signed-off-by: James Bottomley

[SCSI] sd: Reshuffle init_sd to avoid crash

2012-11-27T04:59:34+00:00

scsi_register_driver will register a prep_fn() function, which
in turn migh need to use the sd_cdp_pool for DIF.
Which hasn't been initialised at this point, leading to
a crash. So reshuffle the init_sd() and exit_sd() paths
to have the driver registered last.

Signed-off-by: Joel D. Diaz 
Signed-off-by: Hannes Reinecke 
Signed-off-by: James Bottomley