Introduce struct scsi_vpd for the VPD page length, data and the RCU head
that will be used to free the VPD data. Use kfree_rcu() instead of
kfree() to free VPD data. Move the VPD buffer pointer check inside the
RCU read lock in the sysfs code. Only annotate pointers that are shared
across threads with __rcu. Use rcu_dereference() when dereferencing an
RCU pointer. This patch suppresses about twenty sparse complaints about
the vpd_pg8[03] pointers. This patch also fixes a race condition, namely
that updating of the VPD pointers and length variables in struct
scsi_device was not atomic with reference to the code reading these
variables. See also "Does the update code tolerate concurrent accesses?"
in Documentation/RCU/checklist.txt.
Fixes: commit 09e2b0b146 ("scsi: rescan VPD attributes")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Shane Seymour <shane.seymour@hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Introduce the scsi_get_vpd_buf() and scsi_update_vpd_page()
functions. The only functional change in this patch is that if updating
page 0x80 fails that it is attempted to update page 0x83.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Shane M Seymour <shane.seymour@hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Defaulting to scsi-mq in 4.13-rc has shown various regressions
on setups that we didn't previously consider. Fixes for them are
in progress, but too invasive to make it in this cycle. So for
now revert the commit that defaults to blk-mq for SCSI. For 4.14
we'll plan to try again with these fixes.
This reverts commit 5c279bd9e4.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Remove the SCSI_MQ_DEFAULT config option and default to the blk-mq I/O
path now that we had plenty of testing, and have I/O schedulers for
blk-mq. The module option to disable the blk-mq path is kept around for
now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Just like for the scsi-mq code path, in the single queue SCSI code path
only add commands to the per-device command list if required by the SCSI
LLD. This patch will make it easier to merge the single-queue and
multiqueue command initialization code.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
When a device is unplugged from a SCSI controller, if the scsi_device is
still in use by application layer, it won't get released until users
close it.
In this case, scsi_device_remove just set the scsi_device's state to be
SDEV_DEL. But if you plug the disk just before the old scsi_device is
released, then there will be two scsi_device structures in
scsi_host->__devices. When the next unplug event happens, some low-level
drivers will check whether the scsi_device has been added to host (for
example the MegaRAID SAS series controller) by calling
scsi_device_lookup(call __scsi_device_lookup) in function
megasas_aen_polling. __scsi_device_lookup will return the first
scsi_device. Because its state is SDEV_DEL, the scsi_device_lookup will
return NULL, making the low-level driver assume that the scsi_device has
been removed, and won't call scsi_device_remove which will lead to hot
swap failure.
Signed-off-by: Zhou Zhengping <johnzzpcrystal@gmail.com>
Tested-by: Zeng Rujia <ZengRujia@sangfor.com.cn>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195607
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This can be used to check for fs vs non-fs requests and basically
removes all knowledge of BLOCK_PC specific from the block layer,
as well as preparing for removing the cmd_type field in struct request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Rely on the new block layer functionality to allocate additional driver
specific data behind struct request instead of implementing it in SCSI
itѕelf.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
There is no need for GFP_DMA allocations of the scsi_cmnd structures
themselves, all that might be DMAed to or from is the actual payload,
or the sense buffers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently blk-mq always allocates the sense buffer using normal GFP_KERNEL
allocation. Refactor the cmd pool code to split the cmd and sense allocation
and share the code to allocate the sense buffers as well as the sense buffer
slab caches between the legacy and blk-mq path.
Note that this switches to lazy allocation of the sense slab caches - the
slab caches (not the actual allocations) won't be destroy until the scsi
module is unloaded instead of keeping track of hosts using them.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When using the slab allocator we already decide at cache creation time if
an allocation comes from a GFP_DMA pool using the SLAB_CACHE_DMA flag,
and there is no point passing the kmalloc-family only GFP_DMA flag to
kmem_cache_alloc. Drop all the infrastructure for doing so.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
For blk-mq, ->nr_requests does track queue depth, at least at init
time. But for the older queue paths, it's simply a soft setting.
On top of that, it's generally larger than the hardware setting
on purpose, to allow backup of requests for merging.
Fill a hole in struct request with a 'queue_depth' member, that
drivers can call to more closely inform the block layer of the
real queue depth.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Jan Kara <jack@suse.cz>
This patch avoids that the following memory leak is triggered if
use_blk_mq is disabled after a SCSI host has been allocated by the
ib_srp driver and before the same SCSI host is freed:
unreferenced object 0xffff8803a168c568 (size 256):
backtrace:
[<ffffffff81620c95>] kmemleak_alloc+0x45/0xa0
[<ffffffff811bb104>] __kmalloc_node+0x1e4/0x400
[<ffffffff81309fe4>] blk_mq_alloc_tag_set+0xb4/0x230
[<ffffffff814731b7>] scsi_mq_setup_tags+0xc7/0xd0
[<ffffffff81469c26>] scsi_add_host_with_dma+0x216/0x2d0
[<ffffffffa064bef5>] srp_create_target+0xe55/0x13d0 [ib_srp]
[<ffffffff8143ce23>] dev_attr_store+0x13/0x20
[<ffffffff8125f030>] sysfs_kf_write+0x40/0x50
[<ffffffff8125e397>] kernfs_fop_write+0x137/0x1c0
[<ffffffff811d8c13>] __vfs_write+0x23/0x140
[<ffffffff811d92e0>] vfs_write+0xb0/0x190
[<ffffffff811da5b4>] SyS_write+0x44/0xa0
[<ffffffff8162c8a5>] entry_SYSCALL_64_fastpath+0x18/0xa8
Fixes: 9aa9cc4221 ("scsi: remove the disable_blk_mq host flag")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
We've had scsi-mq for 2.5 years now, so we can remove the unused flag to
disable the code on a per-host basis that was put in for unexpected
emergencies during bringup.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The patch "scsi: rescan VPD attributes" introduced a regression in which
devices that don't support VPD were being scanned for VPD attributes
anyway. This could cause issues for some devices and should be avoided
so the check for scsi_level has been moved out of scsi_add_lun and into
scsi_attach_vpd so that all callers will not scan VPD for devices that
don't support it.
[mkp: Merge fix]
Fixes: 09e2b0b146 ("scsi: rescan VPD attributes")
Cc: <stable@vger.kernel.org> #v4.5+
Suggested-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The VPD page information might change, so we need to be able to update
it. This patch implements a VPD page rescan whenever the 'rescan' sysfs
attribute is triggered.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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 <hch@lst.de>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Move the functions that are used by both the initiator and target
subsystems into scsi_common.c/.h. This change will allow to remove
the initiator SCSI header include directives from most SCSI target
source files in a later patch.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
This effectively reverts commits 85b6c7 ("[SCSI] sd: fix cache flushing on
module removal (and individual device removal)" and dc4515ea ("scsi: always
increment reference count").
We now never call scsi_device_get from the shutdown path, and the fact
that we started grabbing reference there in commit 85b6c7 turned out
turned out to create more problems than it solves, and required
workarounds for workarounds for workarounds. Move back to properly checking
the device state and carefully handle module refcounting.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This is the usual grab bag of driver updates (hpsa, storvsc, mp2sas,
megaraid_sas, ses) plus an assortment of minor updates. There's also an
update to ufs which adds new phy drivers and finally a new logging
infrastructure for SCSI.
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull first round of SCSI updates from James Bottomley:
"This is the usual grab bag of driver updates (hpsa, storvsc, mp2sas,
megaraid_sas, ses) plus an assortment of minor updates.
There's also an update to ufs which adds new phy drivers and finally a
new logging infrastructure for SCSI"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (114 commits)
scsi_logging: return void for dev_printk() functions
scsi: print single-character strings with seq_putc
scsi: merge consecutive seq_puts calls
scsi: replace seq_printf with seq_puts
aha152x: replace seq_printf with seq_puts
advansys: replace seq_printf with seq_puts
scsi: remove SPRINTF macro
sg: remove an unused variable
hpsa: Use local workqueues instead of system workqueues
hpsa: add in P840ar controller model name
hpsa: add in gen9 controller model names
hpsa: detect and report failures changing controller transport modes
hpsa: shorten the wait for the CISS doorbell mode change ack
hpsa: refactor duplicated scan completion code into a new routine
hpsa: move SG descriptor set-up out of hpsa_scatter_gather()
hpsa: do not use function pointers in fast path command submission
hpsa: print CDBs instead of kernel virtual addresses for uncommon errors
hpsa: do not use a void pointer for scsi_cmd field of struct CommandList
hpsa: return failed from device reset/abort handlers
hpsa: check for ctlr lockup after command allocation in main io path
...
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 <James.Bottomley@HansenPartnership.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
scsi_log_send() would display buffer pointer for higher logging levels.
This is not only of questionable value but also exposes kernel pointer to
userspace, which is discouraged in some setups. So drop this message
altogether.
Tested-by: Robert Elliott <elliott@hp.com>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Convert scsi_print_result() to use the per-cpu buffer for decoding the
command result and disposition.
Tested-by: Robert Elliott <elliott@hp.com>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Conflicts:
drivers/scsi/scsi_debug.c
Agreed and tested resolution to a merge problem between a fix in scsi_debug
and a driver update
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com
Reviewed-by: Hannes Reinecke <hare@suse.de>
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 <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com
Reviewed-by: Hannes Reinecke <hare@suse.de>
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 <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes 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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
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 <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
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 <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
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 <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Most drivers use exactly the same implementation, so provide it as a
library function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Simplify scsi_log_(send|completion) by externalizing
scsi_mlreturn_string() and always print the command address.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph 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: Hannes Reinecke <hare@suse.de>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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 <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Robert Elliott <elliott@hp.com>
Tested-by: Robert Elliott <elliott@hp.com>
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 <stern@rowland.harvard.edu>
Reported-by: Tiziano Bacocco <tiziano.bacocco@gmail.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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 <jgross@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Fixes: 89d9a56795
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
hostt->name might contain space, so use the ->proc_name short name instead
when creating per-driver command slabs.
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Reported-by: poma <pomidorabelisima@gmail.com>
Tested-by: poma <pomidorabelisima@gmail.com>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
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 <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
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 <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
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 <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
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 <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
Make sure we only have the logic for requeing commands in one place.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
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 <dgilbert@interlog.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Robert Elliott <elliott@hp.com>
Tested-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Using dev_printk variants prefixes the logging message with
the originating device, which makes debugging easier.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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 <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
