Commit ac61d195 (scsi: set correct completion code in
scsi_send_eh_cmnd()) introduced a bug.  It changed the stored return
value from a queuecommand call, but it didn't take into account that
the return value was used again later on.  This patch fixes the bug by
changing the later usage.

There is a big comment in the middle of scsi_send_eh_cmnd() which
does a good job of explaining how the routine works.  But it mentions
a "rtn = FAILURE" value that doesn't exist in the code.  This patch
adjusts the code to match the comment (I assume the comment is right
and the code is wrong).

This fixes Bugzilla #88341.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-by: NАндрей Аладьев <aladjev.andrew@gmail.com>
Tested-by: NАндрей Аладьев <aladjev.andrew@gmail.com>
Fixes: ac61d195Acked-by: NHannes Reinecke <hare@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

scsi_reset_provider already manually runs all queues for the given host,
so it doesn't need the scsi_run_queues call from it, and it doesn't need
a reference on the device because it's synchronous.

So let's just call scsi_put_command directly and avoid the device reference
dance to simplify the code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NHannes Reinecke <hare@suse.de>

Drop the now unused reason argument from the ->change_queue_depth method.
Also add a return value to scsi_adjust_queue_depth, and rename it to
scsi_change_queue_depth now that it can be used as the default
->change_queue_depth implementation.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

All drivers use the implementation for ramping the queue up and down, so
instead of overloading the change_queue_depth method call the
implementation diretly if the driver opts into it by setting the
track_queue_depth flag in the host template.

Note that a few drivers validated the new queue depth in their
change_queue_depth method, but as we never go over the queue depth
set during slave_configure or the sysfs file this isn't nessecary
and can safely be removed.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NVenkatesh Srinivas <venkateshs@google.com>

Pull the common code from the two callers into the function,
and rename it to scsi_ioctl_reset.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>

scsi_try_to_abort_cmd() should only return SUCCESS, FAILED, or
FAST_IO_FAIL. So document that in the function description and simplify
the logging message.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Suggested-by: NChristoph Hellwig <hch@infradead.org>
Reviewed-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The EH statistics are per host, so we should be using
shost_printk() here.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Suggested-by: NRobert Elliott <elliott@hp.com>
Reviewed-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Use the matching scope for logging messages to allow for
better command tracing.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Suggested-by: NRobert Elliott <elliott@hp.com>
Reviewed-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Convert scsi_normalize_sense() and friends to return 'bool'
instead of an integer.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NRobert Elliott <elliott@hp.com>
Reviewed-by: NYoshihiro Yunomae <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We should be using the standard dev_printk() variants for
sense code printing.

[hch: remove __scsi_print_sense call in xen-scsiback, Acked by Juergen]
[hch: folded bracing fix from Dan Carpenter]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Further to a January 2013 thread titled: "[PATCH] SG_SCSI_RESET ioctl
should only perform requested operation" by Jeremy Linton a patch (v3)
is presented that expands the existing ioctl to include "no_escalate"
versions to the existing resets. This requires no changes to SCSI low
level drivers (LLDs); it adds several more finely tuned reset options
to the user space. For example:

   /* This call remains the same, with the same escalating semantics
    * if the device (LU) reset fail. That is: on failure to try a
    * target reset and if that fails, try a bus reset, and if that fails
    * try a host (i.e. LLD) reset. */
   val = SG_SCSI_RESET_DEVICE;
   res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val);

   /* What follows is a new option introduced by this patch series. Only
    * a device reset is attempted. If that fails then an appropriate
    * error code is provided. N.B. There is no reset escalation. */
   val = SG_SCSI_RESET_DEVICE | SG_SCSI_RESET_NO_ESCALATE;
   res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val);
Signed-off-by: NDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: NJeremy Linton <jlinton@tributary.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Multipath devices using the TUR path checker need to see the sense
code for a failed TUR command in their device handler.  Since commit
14216561 we always return success for mid
layer issued TUR commands before calling the device handler, which
stopped the TUR path checker from working.

Move the call to the device handler check sense method before the early
return for TUR commands to give the device handler a chance to intercept
them.
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Tested-by: NWen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>

Setups that use the blk-mq I/O path can lock up if a host with a single
device that has its door locked enters EH.  Make sure to only send the
command to re-lock the door to devices that actually were reset and thus
might have lost their state.  Otherwise the EH code might be get blocked
on blk_get_request as all requests for non-reset devices might be in use.

Cc: stable@vger.kernel.org
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NMeelis Roos <meelis.roos@ut.ee>
Tested-by: NMeelis Roos <meelis.roos@ut.ee>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>

Convert spaces to tabs in kernel-doc notation.
Correct duplicated (copy-paste) kernel-doc comments that are incorrect.
Fix kernel-doc warning:

Warning(..//drivers/scsi/scsi_error.c:1647): No description found for parameter 'shost'
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The blk_get_request function may fail in low-memory conditions or during
device removal (even if __GFP_WAIT is set). To distinguish between these
errors, modify the blk_get_request call stack to return the appropriate
ERR_PTR. Verify that all callers check the return status and consider
IS_ERR instead of a simple NULL pointer check.

For consistency, make a similar change to the blk_mq_alloc_request leg
of blk_get_request.  It may fail if the queue is dead, or the caller was
unwilling to wait.
Signed-off-by: NJoe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Acked-by: Boaz Harrosh <bharrosh@panasas.com> [for osd]
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

The blk-core dead queue checks introduce an error scenario to
blk_get_request that returns NULL if the request queue has been
shutdown. This affects the behavior for __GFP_WAIT callers, who should
verify the return value before dereferencing.
Signed-off-by: NJoe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Avoid taking the host-wide host_lock to check the per-host queue limit.
Instead we do an atomic_inc_return early on to grab our slot in the queue,
and if necessary decrement it after finishing all checks.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NWebb Scales <webbnh@hp.com>
Acked-by: NJens Axboe <axboe@kernel.dk>
Tested-by: NBart Van Assche <bvanassche@acm.org>
Tested-by: NRobert Elliott <elliott@hp.com>

Using dev_printk variants prefixes the logging message with
the originating device, which makes debugging easier.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

scsi_put_command() is either invoked before blk_start_request() or
after block layer processing has completed.  scsi_cmnd.abort_work
is scheduled from inside the SCSI timeout handler.  The block layer
guarantees that either the regular completion handler
(softirq_done_fn()) or the timeout handler (rq_timed_out_fn()) is
invoked but not both. This means that scsi_put_command() is never
invoked while abort_work is scheduled.  Hence remove the
cancel_delayed_work() call from scsi_put_command().

Similarly, scsi_abort_command() is only invoked from the SCSI
timeout handler. If scsi_abort_command() is invoked for a SCSI
command with the SCSI_EH_ABORT_SCHEDULED flag set this means that
scmd_eh_abort_handler() has already invoked scsi_queue_insert() and
hence that scsi_cmnd.abort_work is no longer pending. Hence also
remove the cancel_delayed_work() call from scsi_abort_command().
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Any callbacks in scsi_timeout_out() might return BLK_EH_RESET_TIMER,
in which case we should leave the result alone and not set
DID_TIME_OUT, as the command didn't actually timeout.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>

After scsi_try_to_abort_cmd returns, the eh_abort_handler may have
already found that the command has completed in the device, causing
the host_byte to be nonzero (e.g. it could be DID_ABORT).  When
this happens, ORing DID_TIME_OUT into the host byte will corrupt
the result field and initiate an unwanted command retry.

Fix this by using set_host_byte instead, following the model of
commit 2082ebc4.

Cc: stable@vger.kernel.org
Signed-off-by: NUlrich Obergfell <uobergfe@redhat.com>
[Fix all instances according to review comments. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>

With the optimizations around not clearing the full request at alloc
time, we are leaving some of the needed init for REQ_TYPE_BLOCK_PC
up to the user allocating the request.

Add a blk_rq_set_block_pc() that sets the command type to
REQ_TYPE_BLOCK_PC, and properly initializes the members associated
with this type of request. Update callers to use this function instead
of manipulating rq->cmd_type directly.

Includes fixes from Christoph Hellwig <hch@lst.de> for my half-assed
attempt.
Signed-off-by: NJens Axboe <axboe@fb.com>

->queuecommand returns '0' for successful command submission,
so we need to set the correct SCSI midlayer return value
when calling scsi_log_completion().
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reported-by: NRobert Elliott <elliott@hp.com>
Cc: Stephen Cameron <scameron@beardog.cce.hp.com>
Tested-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NNicholas Bellinger <nab@linux-iscsi.org>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

This patch fixes a corner case in the previous USB Deadlock fix patch (12023e7
[SCSI] Fix USB deadlock caused by SCSI error handling).

The scenario is abort command, set flag, abort completes, send TUR, TUR
doesn't return, so we now try to abort the TUR, but scsi_abort_eh_cmnd()
will skip the abort because the flag is set and move straight to reset.
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

USB requires that every command be aborted first before we escalate to reset.
In particular, USB will deadlock if we try to reset first before aborting the
command.

Unfortunately, the flag we use to tell if a command has already been aborted:
SCSI_EH_ABORT_SCHEDULED is not cleared properly leading to cases where we can
requeue a command with the flag set and proceed immediately to reset if it
fails (thus causing USB to deadlock).

Fix by clearing the SCSI_EH_ABORT_SCHEDULED flag if it has been set.  Which
means this will be the second time scsi_abort_command() has been called for
the same command.  IE the first abort went out, did its thing, but now the
same command has timed out again.

So this flag gets cleared, and scsi_abort_command() returns FAILED, and _no_
asynchronous abort is being scheduled.  scsi_times_out() will then proceed to
call scsi_eh_scmd_add().  But as we've cleared the SCSI_EH_ABORT_SCHEDULED
flag the SCSI_EH_CANCEL_CMD flag will continue to be set, and the command will
be aborted with the main SCSI EH routine.
Reported-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NAndreas Reis <andreas.reis@gmail.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

We're seeing a case where the contents of scmd->result isn't being reset after
a SCSI command encounters an error, is resubmitted, times out and then gets
handled.  The error handler acts on the stale result of the previous error
instead of the timeout.  Fix this by properly zeroing the scmd->status before
the command is resubmitted.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

We unconditionally execute scsi_eh_get_sense() to make sure all failed
commands that should have sense attached, do.  However, the routine forgets
that some commands, because of the way they fail, will not have any sense code
... we should not bother them with a REQUEST_SENSE command.  Fix this by
testing to see if we actually got a CHECK_CONDITION return and skip asking for
sense if we don't.
Tested-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Many callers won't need this and we can optimize them away.  In addition
the handling in the __-prefixed variants was inconsistant to start with.

Based on an earlier patch from Bart Van Assche.

[jejb: fix kerneldoc probelm picked up by Fengguang Wu]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

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: NRen Mingxin <renmx@cn.fujitsu.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

32bit accesses are guaranteed to be atomic, so we can remove
the spinlock when checking for eh_deadline. We only need to
make sure to catch any updates which might happened during
the call to time_before(); if so we just recheck with the
correct value.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

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: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Commit 18a4d0a2
(Handle disk devices which can not process medium access commands)
was introduced to offline any device which cannot process medium
access commands.
However, commit 3eef6257
(Reduce error recovery time by reducing use of TURs) reduced
the number of TURs by sending it only on the first failing
command, which might or might not be a medium access command.
So in combination this results in an erratic device offlining
during EH; if the command where the TUR was sent upon happens
to be a medium access command the device will be set offline,
if not everything proceeds as normal.

This patch moves the check to the final test, eliminating
this problem.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

If a command abort fails there is a fair chance that all other
aborts will be failing, too.
So we should be calling LUN reset directly after the first failed
abort and skip aborting the remaining commands.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This patchs adds an 'eh_deadline' sysfs attribute to the scsi
host which limits the overall runtime of the SCSI EH.
The 'eh_deadline' value is stored in the now obsolete field
'resetting'.
When a command is failed the start time of the EH is stored
in 'last_reset'. If the overall runtime of the SCSI EH is longer
than last_reset + eh_deadline, the EH is short-circuited and
falls through to issue a host reset only.

[jejb: add comments in Scsi_Host about new fields]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Generate a uevent when the following Unit Attention ASC/ASCQ
codes are received:

    2A/01  MODE PARAMETERS CHANGED
    2A/09  CAPACITY DATA HAS CHANGED
    38/07  THIN PROVISIONING SOFT THRESHOLD REACHED
    3F/03  INQUIRY DATA HAS CHANGED
    3F/0E  REPORTED LUNS DATA HAS CHANGED

Log kernel messages when the following Unit Attention ASC/ASCQ
codes are received that are not as specific as those above:

    2A/xx  PARAMETERS CHANGED
    3F/xx  TARGET OPERATING CONDITIONS HAVE CHANGED

Added logic to set expecting_lun_change for other LUNs on the target
after REPORTED LUNS DATA HAS CHANGED is received, so that duplicate
uevents are not generated, and clear expecting_lun_change when a
REPORT LUNS command completes, in accordance with the SPC-3
specification regarding reporting of the 3F 0E ASC/ASCQ UA.

[jejb: remove SPC3 test in scsi_report_lun_change and some docbook fixes and
       unused variable fix, both reported by Fengguang Wu]
Signed-off-by: NEwan D. Milne <emilne@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When a medium error is detected the SCSI stack should return
ENODATA to the upper layers.

[jejb: fix whitespace error]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When the thin provisioning hard threshold is reached we
should return ENOSPC to inform upper layers about this fact.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

We should be modifying the host_byte status in scsi_check_sense()
directly; this saves us to introduce a special return code for
each and every condition.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Introduce eh_timeout which can be used for error handling purposes. This
was previously hardcoded to 10 seconds in the SCSI error handling
code. However, for some fast-fail scenarios it is necessary to be able
to tune this as it can take several iterations (bus device, target, bus,
controller) before we give up.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>