23 Jan, 2015
1 commit
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James reported:
> After e513cc1 module: Remove stop_machine from module unloading,
> module_refcount() is returning (unsigned long)-1 when called from within
> a routine that runs in module_exit. This is confusing the scsi device
> put code which is coded to detect a module_refcount() of zero for
> running within a module exit routine and not try to do another
> module_put. The fix is to restore the original behaviour of
> module_refcount() and return zero if we're running inside an exit
> routine.The correct fix is to turn try_module_get() into __module_get(), and
always do the module_put().Acked-by: James Bottomley
Signed-off-by: Rusty Russell
18 Dec, 2014
1 commit
08 Dec, 2014
1 commit
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Conflicts:
drivers/scsi/scsi_debug.cAgreed and tested resolution to a merge problem between a fix in scsi_debug
and a driver updateSigned-off-by: James Bottomley
04 Dec, 2014
2 commits
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Dropping to untagged mode when ramping down a queue due to QUEUE FULL
events has two problems:- nothing in the midlayer or drivers ever moves back to tagged mode
during queue ramp up.
- cmd_per_lun isn't the untagged queue depth for many modern drivers
that can handle multiple untagged commands, and this is the only
place in the midlayer assuming that.Signed-off-by: Christoph Hellwig
Reviewed-by: Bart Van Assche
Reviewed-by: Martin K. Petersen -
Since we got rid of ordered tag support in 2010 the prime use case of
switching on and off ordered tags has been obsolete. The other function
of enabling/disabling tagging entirely has only been correctly implemented
by the 53c700 driver and isn't generally useful.Signed-off-by: Christoph Hellwig
Reviewed-by: Bart Van Assche
Reviewed-by: Martin K. Petersen
25 Nov, 2014
1 commit
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scsi_lib.c is where the rest of the I/O submission path lives, so move
scsi_dispatch_cmd there and mark it static.Signed-off-by: Christoph Hellwig
Reviewed-by: Bart Van Assche
Reviewed-by: Hannes Reinecke
24 Nov, 2014
1 commit
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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: Christoph Hellwig
Reviewed-by: Mike Christie
Reviewed-by: Hannes Reinecke
12 Nov, 2014
6 commits
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Remove the tagged argument from scsi_adjust_queue_depth, and just let it
handle the queue depth. For most drivers those two are fairly separate,
given that most modern drivers don't care about the SCSI "tagged" status
of a command at all, and many old drivers allow queuing of multiple
untagged commands in the driver.Instead we start out with the ->simple_tags flag set before calling
->slave_configure, which is how all drivers actually looking at
->simple_tags except for one worke anyway. The one other case looks
broken, but I've kept the behavior as-is for now.Except for that we only change ->simple_tags from the ->change_queue_type,
and when rejecting a tag message in a single driver, so keeping this
churn out of scsi_adjust_queue_depth is a clear win.Now that the usage of scsi_adjust_queue_depth is more obvious we can
also remove all the trivial instances in ->slave_alloc or ->slave_configure
that just set it to the cmd_per_lun default.Signed-off-by: Christoph Hellwig
Reviewed-by: Mike Christie
Reviewed-by: Hannes Reinecke
Reviewed-by: Martin K. Petersen -
Allow a driver to ask for block layer tags by setting .use_blk_tags in the
host template, in which case it will always see a valid value in
request->tag, similar to the behavior when using blk-mq. This means even
SCSI "untagged" commands will now have a tag, which is especially useful
when using a host-wide tag map.Signed-off-by: Christoph Hellwig
Reviewed-by: Mike Christie
Reviewed-by: Martin K. Petersen
Reviewed-by: Hannes Reinecke -
Remove the ordered_tags field, we haven't been issuing ordered tags based
on it since the big barrier rework in 2010.Signed-off-by: Christoph Hellwig
Reviewed-by: Mike Christie
Reviewed-by: Bart Van Assche
Reviewed-by: Martin K. Petersen -
Most drivers use exactly the same implementation, so provide it as a
library function.Signed-off-by: Christoph Hellwig
Reviewed-by: Bart Van Assche
Reviewed-by: Mike Christie
Reviewed-by: Martin K. Petersen
Reviewed-by: Hannes Reinecke -
Simplify scsi_log_(send|completion) by externalizing
scsi_mlreturn_string() and always print the command address.Signed-off-by: Hannes Reinecke
Reviewed-by: Robert Elliott
Signed-off-by: Christoph Hellwig -
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: Hannes Reinecke
Reviewed-by: Robert Elliott
Signed-off-by: Christoph Hellwig
01 Oct, 2014
1 commit
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Add a Kconfig option to enable the blk-mq path for SCSI by default
to ease testing and deployment in setups that know they benefit
from blk-mq.Signed-off-by: Christoph Hellwig
Reviewed-by: Martin K. Petersen
Reviewed-by: Robert Elliott
Tested-by: Robert Elliott
16 Sep, 2014
1 commit
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The SCSI specification requires that the second Command Data Byte
should contain the LUN value in its high-order bits if the recipient
device reports SCSI level 2 or below. Nevertheless, some USB
mass-storage devices use those bits for other purposes in
vendor-specific commands. Currently Linux has no way to send such
commands, because the SCSI stack always overwrites the LUN bits.Testing shows that Windows 7 and XP do not store the LUN bits in the
CDB when sending commands to a USB device. This doesn't matter if the
device uses the Bulk-Only or UAS transports (which virtually all
modern USB mass-storage devices do), as these have a separate
mechanism for sending the LUN value.Therefore this patch introduces a flag in the Scsi_Host structure to
inform the SCSI midlayer that a transport does not require the LUN
bits to be stored in the CDB, and it makes usb-storage set this flag
for all devices using the Bulk-Only transport. (UAS is handled by a
separate driver, but it doesn't really matter because no SCSI-2 or
lower device is at all likely to use UAS.)The patch also cleans up the code responsible for storing the LUN
value by adding a bitflag to the scsi_device structure. The test for
whether to stick the LUN value in the CDB can be made when the device
is probed, and stored for future use rather than being made over and
over in the fast path.Signed-off-by: Alan Stern
Reported-by: Tiziano Bacocco
Acked-by: Martin K. Petersen
Acked-by: James Bottomley
Signed-off-by: Christoph Hellwig
16 Aug, 2014
1 commit
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If a scsi host driver specifies .cmd_len in it's scsi_host_template, a driver's
private command pool is needed. scsi_find_host_cmd_pool() will locate it, but
scsi_alloc_host_cmd_pool() isn't saving the pool address in the host template.This will result in an access error when the host is removed.
Avoid the problem by saving the address of a new allocated command pool where
it is expected.Signed-off-by: Juergen Gross
Reviewed-by: Hannes Reinecke
Signed-off-by: Christoph Hellwig
Fixes: 89d9a567952baec13e26ada3e438f1b642d66b6e
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley
29 Jul, 2014
1 commit
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hostt->name might contain space, so use the ->proc_name short name instead
when creating per-driver command slabs.Signed-off-by: James Bottomley
Reported-by: poma
Tested-by: poma
Reviewed-by: Vladimir Davydov
Reviewed-by: Martin K. Petersen
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig
26 Jul, 2014
3 commits
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Add two new device types, most importantly the zoned block device
one.Split from an earlier patch by Hannes Reinecke.
Signed-off-by: Christoph Hellwig
Reviewed-by: Hannes Reinecke
Reviewed-by: Martin K. Petersen -
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 -
Seems like these counters are missing any sort of synchronization for
updates, as a over 10 year old comment from me noted. Fix this by
using atomic counters, and while we're at it also make sure they are
in the same cacheline as the _busy counters and not needlessly stored
to in every I/O completion.With the new model the _busy counters can temporarily go negative,
so all the readers are updated to check for > 0 values. Longer
term every successful I/O completion will reset the counters to zero,
so the temporarily negative values will not cause any harm.Signed-off-by: Christoph Hellwig
Reviewed-by: Martin K. Petersen
Reviewed-by: Webb Scales
Acked-by: Jens Axboe
Tested-by: Bart Van Assche
Tested-by: Robert Elliott
25 Jul, 2014
3 commits
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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: 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 -
The blk-mq code path will set this to a different function, so make the
code simpler by setting it up in a legacy-request specific place.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 -
Make sure we only have the logic for requeing commands in one place.
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
18 Jul, 2014
5 commits
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While checking what scsi_adjust_queue_depth() did I thought its switch
statement could be clearer:- remove redundant assignment (to sdev->queue_depth)
- re-order cases (thus removing the fall-through)Signed-off-by: Douglas Gilbert
Reviewed-by: Martin K. Petersen
Reviewed-by: Robert Elliott
Tested-by: Robert Elliott
Signed-off-by: Christoph Hellwig -
Signed-off-by: Christoph Hellwig
Reviewed-by: Paolo Bonzini
Reviewed-by: Hannes Reinecke -
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 -
The SCSI standard defines 64-bit values for LUNs, and large arrays
employing large or hierarchical LUN numbers become more and more
common.So update the linux SCSI stack to use 64-bit LUN numbers.
Signed-off-by: Hannes Reinecke
Reviewed-by: Christoph Hellwig
Reviewed-by: Ewan Milne
Signed-off-by: Christoph Hellwig -
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: Bart Van Assche
Reviewed-by: Hannes Reinecke
Signed-off-by: Christoph Hellwig
12 Apr, 2014
1 commit
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Pull async SCSI resume support from Dan Williams:
"Allow disks and other devices to resume in parallel.This provides a tangible speed up for a non-esoteric use case (laptop
resume):https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach"
* 'async-scsi-resume' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/isci:
scsi: async sd resume
11 Apr, 2014
1 commit
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async_schedule() sd resume work to allow disks and other devices to
resume in parallel.This moves the entirety of scsi_device resume to an async context to
ensure that scsi_device_resume() remains ordered with respect to the
completion of the start/stop command. For the duration of the resume,
new command submissions (that do not originate from the scsi-core) will
be deferred (BLKPREP_DEFER).It adds a new ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain) as a container
of these operations. Like scsi_sd_probe_domain it is flushed at
sd_remove() time to ensure async ops do not continue past the
end-of-life of the sdev. The implementation explicitly refrains from
reusing scsi_sd_probe_domain directly for this purpose as it is flushed
at the end of dpm_resume(), potentially defeating some of the benefit.
Given sdevs are quiesced it is permissible for these resume operations
to bleed past the async_synchronize_full() calls made by the driver
core.We defer the resolution of which pm callback to call until
scsi_dev_type_{suspend|resume} time and guarantee that the callback
parameter is never NULL. With this in place the type of resume
operation is encoded in the async function identifier.There is a concern that async resume could trigger PSU overload. In the
enterprise, storage enclosures enforce staggered spin-up regardless of
what the kernel does making async scanning safe by default. Outside of
that context a user can disable asynchronous scanning via a kernel
command line or CONFIG_SCSI_SCAN_ASYNC. Honor that setting when
deciding whether to do resume asynchronously.Inspired by Todd's analysis and initial proposal [2]:
https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approachCc: Len Brown
Cc: Phillip Susi
[alan: bug fix and clean up suggestion]
Acked-by: Alan Stern
Suggested-by: Todd Brandt
[djbw: kick all resume work to the async queue]
Signed-off-by: Dan Williams
27 Mar, 2014
5 commits
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This allows drivers to specify the size of their per-command private
data in the host template and then get extra memory allocated for
each command instead of needing another allocation in ->queuecommand.With the current SCSI code that already does multiple allocations for
each command this probably doesn't make a big performance impact, but
it allows to clean up the drivers, and prepare them for using the
blk-mq infrastructure where the common allocation will make a difference.Signed-off-by: Christoph Hellwig
Reviewed-by: Paolo Bonzini
Signed-off-by: James Bottomley -
Just have one level of alloc/free functions that take a host instead
of two levels for the allocation and different calling conventions
for the free.[fengguang.wu@intel.com: docbook problems spotted, now fixed]
Signed-off-by: Christoph Hellwig
Reviewed-by: Paolo Bonzini
Signed-off-by: James Bottomley -
We don't use the passed in scsi command for anything, so just add a adapter-
wide internal status to go along with the internal scb that is used unter
int_mtx to pass back the return value and get rid of all the complexities
and abuse of the scsi_cmnd structure.This gets rid of the only user of scsi_allocate_command/scsi_free_command,
which can now be removed.[jejb: checkpatch fixes]
Signed-off-by: Christoph Hellwig
Acked-by: Adam Radford
Signed-off-by: James Bottomley -
EVPD page 0x83 is used to uniquely identify the device.
So instead of having each and every program issue a separate
SG_IO call to retrieve this information it does make far more
sense to display it in sysfs.Some older devices (most notably tapes) will only report reliable
information in page 0x80 (Unit Serial Number). So export this
in the sysfs attribute 'vpd_pg80'.[jejb: checkpatch fix]
[hare: attach after transport configure]
[fengguang.wu@intel.com: spotted problems with the original now fixed]
Signed-off-by: Hannes Reinecke
Signed-off-by: James Bottomley -
We should be returning the number of bytes of the
requested VPD page in scsi_vpd_inquiry.
This makes it easier for the caller to verify the
required space.[jejb: fix up mm warning spotted by Sergey]
Tested-by: Sergey Senozhatsky
Signed-off-by: Hannes Reinecke
Signed-off-by: James Bottomley
16 Mar, 2014
2 commits
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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: Christoph Hellwig
Reviewed-by: Hannes Reinecke
Signed-off-by: James Bottomley -
Avoid hitting the host-wide free_list lock unless we need to put a command
back onto the freelist.Signed-off-by: Christoph Hellwig
Reviewed-by: Hannes Reinecke
Signed-off-by: James Bottomley
19 Dec, 2013
2 commits
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The documentation has gone out-of-sync, so update it to
the current status.Signed-off-by: Hannes Reinecke
Signed-off-by: James Bottomley -
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
25 Oct, 2013
1 commit
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Field is now unused, so this is dead code.
[jejb: remove resetting and last_reset from Scsi_Host]
Signed-off-by: Hannes Reinecke
Signed-off-by: James Bottomley