linux-toradex.git/drivers/scsi/hosts.c, branch v4.4.63

Merge branch 'mkp-fixes' into fixes

2015-12-03T17:32:33+00:00

Fix a memory leak in scsi_host_dev_release()

2015-12-01T01:33:34+00:00

Avoid that kmemleak reports the following memory leak if a
SCSI LLD calls scsi_host_alloc() and scsi_host_put() but neither
scsi_host_add() nor scsi_host_remove(). The following shell
command triggers that scenario:

for ((i=0; i<2; i++)); do
  srp_daemon -oac |
  while read line; do
    echo $line >/sys/class/infiniband_srp/srp-mlx4_0-1/add_target
  done
done

unreferenced object 0xffff88021b24a220 (size 8):
  comm "srp_daemon", pid 56421, jiffies 4295006762 (age 4240.750s)
  hex dump (first 8 bytes):
    68 6f 73 74 35 38 00 a5                          host58..
  backtrace:
    [] kmemleak_alloc+0x7a/0xc0
    [] __kmalloc_track_caller+0xfe/0x160
    [] kvasprintf+0x5b/0x90
    [] kvasprintf_const+0x8d/0xb0
    [] kobject_set_name_vargs+0x3c/0xa0
    [] dev_set_name+0x3c/0x40
    [] scsi_host_alloc+0x327/0x4b0
    [] srp_create_target+0x4e/0x8a0 [ib_srp]
    [] dev_attr_store+0x1b/0x20
    [] sysfs_kf_write+0x4a/0x60
    [] kernfs_fop_write+0x14e/0x180
    [] __vfs_write+0x2f/0xf0
    [] vfs_write+0xa4/0x100
    [] SyS_write+0x54/0xc0
    [] entry_SYSCALL_64_fastpath+0x12/0x6f

Signed-off-by: Bart Van Assche 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Sagi Grimberg 
Reviewed-by: Lee Duncan 
Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Cc: stable 
Signed-off-by: Martin K. Petersen

scsi: use host wide tags by default

2015-11-10T01:11:57+00:00

This patch changes the !blk-mq path to the same defaults as the blk-mq
I/O path by always enabling block tagging, and always using host wide
tags.  We've had blk-mq available for a few releases so bugs with
this mode should have been ironed out, and this ensures we get better
coverage of over tagging setup over different configs.

Signed-off-by: Christoph Hellwig 
Acked-by: Jens Axboe 
Reviewed-by: Hannes Reinecke 
Signed-off-by: James Bottomley

scsi: remove ordered_tag host template field

2014-11-12T10:19:41+00:00

Signed-off-by: Christoph Hellwig 
Reviewed-by: Bart Van Assche 
Reviewed-by: Mike Christie 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke

scsi: fixup logging messages in scsi_error.c

2014-11-12T10:16:06+00:00

Use the matching scope for logging messages to allow for
better command tracing.

Signed-off-by: Hannes Reinecke 
Suggested-by: Robert Elliott 
Reviewed-by: Robert Elliott 
Signed-off-by: Christoph Hellwig

scsi: add support for a blk-mq based I/O path.

2014-07-25T21:16:28+00:00

This patch adds support for an alternate I/O path in the scsi midlayer
which uses the blk-mq infrastructure instead of the legacy request code.

Use of blk-mq is fully transparent to drivers, although for now a host
template field is provided to opt out of blk-mq usage in case any unforseen
incompatibilities arise.

In general replacing the legacy request code with blk-mq is a simple and
mostly mechanical transformation.  The biggest exception is the new code
that deals with the fact the I/O submissions in blk-mq must happen from
process context, which slightly complicates the I/O completion handler.
The second biggest differences is that blk-mq is build around the concept
of preallocated requests that also include driver specific data, which
in SCSI context means the scsi_cmnd structure.  This completely avoids
dynamic memory allocations for the fast path through I/O submission.

Due the preallocated requests the MQ code path exclusively uses the
host-wide shared tag allocator instead of a per-LUN one.  This only
affects drivers actually using the block layer provided tag allocator
instead of their own.  Unlike the old path blk-mq always provides a tag,
although drivers don't have to use it.

For now the blk-mq path is disable by defauly and must be enabled using
the "use_blk_mq" module parameter.  Once the remaining work in the block
layer to make blk-mq more suitable for slow devices is complete I hope
to make it the default and eventually even remove the old code path.

Based on the earlier scsi-mq prototype by Nicholas Bellinger.

Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and
various sugestions and code contributions.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Webb Scales 
Acked-by: Jens Axboe 
Tested-by: Bart Van Assche 
Tested-by: Robert Elliott

scsi: use dev_printk variants where possible

2014-07-17T20:07:42+00:00

Using dev_printk variants prefixes the logging message with
the originating device, which makes debugging easier.

Signed-off-by: Hannes Reinecke 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christoph Hellwig

[SCSI] scsi_error: disable eh_deadline if no host_reset_handler is set

2014-03-15T17:18:59+00:00

When the host template doesn't declare an eh_host_reset_handler
the eh_deadline mechanism is pointless and will set the
device to offline. So disable eh_deadline if no
eh_host_reset_handler is present.

Signed-off-by: Hannes Reinecke 
Signed-off-by: James Bottomley

[SCSI] Set the minimum valid value of 'eh_deadline' as 0

2013-12-19T15:39:02+00:00

The former minimum valid value of 'eh_deadline' is 1s, which means
the earliest occasion to shorten EH is 1 second later since a
command is failed or timed out. But if we want to skip EH steps
ASAP, we have to wait until the first EH step is finished. If the
duration of the first EH step is long, this waiting time is
excruciating. So, it is necessary to accept 0 as the minimum valid
value for 'eh_deadline'.

According to my test, with Hannes' patchset 'New EH command timeout
handler' as well, the minimum IO time is improved from 73s
(eh_deadline = 1) to 43s(eh_deadline = 0) when commands are timed
out by disabling RSCN and target port.

Signed-off-by: Ren Mingxin 
Signed-off-by: Hannes Reinecke 
Signed-off-by: James Bottomley

[SCSI] improved eh timeout handler

2013-12-19T15:39:02+00:00

When a command runs into a timeout we need to send an 'ABORT TASK'
TMF. This is typically done by the 'eh_abort_handler' LLDD callback.

Conceptually, however, this function is a normal SCSI command, so
there is no need to enter the error handler.

This patch implements a new scsi_abort_command() function which
invokes an asynchronous function scsi_eh_abort_handler() to
abort the commands via the usual 'eh_abort_handler'.

If abort succeeds the command is either retried or terminated,
depending on the number of allowed retries. However, 'eh_eflags'
records the abort, so if the retry would fail again the
command is pushed onto the error handler without trying to
abort it (again); it'll be cleared up from SCSI EH.

[hare: smatch detected stray switch fixed]
Signed-off-by: Hannes Reinecke 
Signed-off-by: James Bottomley