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2015-01-23scsi: always increment reference countRusty Russell1-10/+3
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>
2014-12-18Merge remote-tracking branch 'scsi-queue/drivers-for-3.19' into for-linusJames Bottomley1-22/+0
2014-12-08Merge remote-tracking branch 'scsi-queue/drivers-for-3.19' into for-linusJames Bottomley1-26/+15
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>
2014-12-04scsi: never drop to untagged mode during queue ramp downChristoph Hellwig1-6/+0
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>
2014-12-04scsi: remove ->change_queue_type methodChristoph Hellwig1-16/+0
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>
2014-11-24scsi: move scsi_dispatch_cmd to scsi_lib.cChristoph Hellwig1-81/+0
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>
2014-11-24scsi: drop reason argument from ->change_queue_depthChristoph Hellwig1-26/+15
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>
2014-11-12scsi: don't set tagging state from scsi_adjust_queue_depthChristoph Hellwig1-20/+5
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>
2014-11-12scsi: always assign block layer tags if enabledChristoph Hellwig1-8/+4
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>
2014-11-12scsi: remove ordered_tags scsi_device fieldChristoph Hellwig1-11/+2
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>
2014-11-12scsi: provide a generic change_queue_type methodChristoph Hellwig1-0/+20
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>
2014-11-12scsi: simplify scsi_log_(send|completion)Hannes Reinecke1-37/+6
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>
2014-11-12scsi: use sdev as argument for sense code printingHannes Reinecke1-1/+1
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>
2014-10-01scsi: add a CONFIG_SCSI_MQ_DEFAULT optionChristoph Hellwig1-0/+4
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>
2014-09-16scsi: don't store LUN bits in CDB[1] for USB mass-storage devicesAlan Stern1-6/+2
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>
2014-08-15[SCSI] save command pool address of Scsi_HostJuergen Gross1-2/+10
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: 89d9a567952baec13e26ada3e438f1b642d66b6e Cc: stable@vger.kernel.org Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2014-07-29scsi: use short driver name for per-driver cmd slab cachesJames Bottomley1-2/+2
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>
2014-07-26scsi: update scsi_device_typesChristoph Hellwig1-0/+2
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>
2014-07-26scsi: add support for a blk-mq based I/O path.Christoph Hellwig1-1/+4
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>
2014-07-26scsi: fix the {host,target,device}_blocked counter messChristoph Hellwig1-11/+10
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>
2014-07-25scsi: convert host_busy to atomic_tChristoph Hellwig1-1/+1
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>
2014-07-25scsi: set ->scsi_done before calling scsi_dispatch_cmdChristoph Hellwig1-22/+1
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>
2014-07-25scsi: centralize command re-queueing in scsi_dispatch_fnChristoph Hellwig1-23/+12
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>
2014-07-18scsi: cleanup switch in scsi_adjust_queue_depthDouglas Gilbert1-4/+6
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>
2014-07-18scsi: remove various exports that were only used by scsi_tgtChristoph Hellwig1-7/+3
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-07-18scsi: use dev_printk variants where possibleHannes Reinecke1-9/+9
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>
2014-07-18scsi: use 64-bit LUNsHannes Reinecke1-4/+4
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>
2014-07-18scsi: remove two cancel_delayed_work() calls from the mid-layerBart Van Assche1-1/+1
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 <bvanassche@acm.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-04-12Merge branch 'async-scsi-resume' of ↵Linus Torvalds1-0/+9
git://git.kernel.org/pub/scm/linux/kernel/git/djbw/isci 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
2014-04-11scsi: async sd resumeDan Williams1-0/+9
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-approach Cc: Len Brown <len.brown@intel.com> Cc: Phillip Susi <psusi@ubuntu.com> [alan: bug fix and clean up suggestion] Acked-by: Alan Stern <stern@rowland.harvard.edu> Suggested-by: Todd Brandt <todd.e.brandt@linux.intel.com> [djbw: kick all resume work to the async queue] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2014-03-27[SCSI] add support for per-host cmd poolsChristoph Hellwig1-19/+77
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 <hch@lst.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2014-03-27[SCSI] simplify command allocation and freeing a bitChristoph Hellwig1-42/+25
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 <hch@lst.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2014-03-27[SCSI] megaraid: simplify internal command handlingChristoph Hellwig1-56/+0
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 <hch@lst.de> Acked-by: Adam Radford <aradford@gmail.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2014-03-27[SCSI] Add EVPD page 0x83 and 0x80 to sysfsHannes Reinecke1-0/+87
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 <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2014-03-27[SCSI] Return VPD page length in scsi_vpd_inquiry()Hannes Reinecke1-8/+11
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 <sergey.senozhatsky@gmail.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2014-03-15[SCSI] do not manipulate device reference counts in scsi_get/put_commandChristoph Hellwig1-25/+12
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 <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2014-03-15[SCSI] avoid useless free_list lock roundtripsChristoph Hellwig1-5/+6
Avoid hitting the host-wide free_list lock unless we need to put a command back onto the freelist. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-12-19[SCSI] Update documentationHannes Reinecke1-4/+2
The documentation has gone out-of-sync, so update it to the current status. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-12-19[SCSI] improved eh timeout handlerHannes Reinecke1-0/+3
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 <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-10-25[SCSI] remove check for 'resetting'Hannes Reinecke1-28/+0
Field is now unused, so this is dead code. [jejb: remove resetting and last_reset from Scsi_Host] Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-08-03[SCSI] Don't attempt to send extended INQUIRY command if skip_vpd_pages is setMartin K. Petersen1-0/+3
If a device has the skip_vpd_pages flag set we should simply fail the scsi_get_vpd_page() call. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Stuart Foster <smf.linux@ntlworld.com> Cc: stable@vger.kernel.org Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-06-27[SCSI] sd: Update WRITE SAME heuristicsMartin K. Petersen1-4/+4
SATA drives located behind a SAS controller would incorrectly receive WRITE SAME commands. Tweak the heuristics so that: - If REPORT SUPPORTED OPERATION CODES is provided we will use that to choose between WRITE SAME(16), WRITE SAME(10) and disabled. This also fixes an issue with the old code which would issue WRITE SAME(10) despite the command not being whitelisted in REPORT SUPPORTED OPERATION CODES. - If REPORT SUPPORTED OPERATION CODES is not provided we will fall back to WRITE SAME(10) unless the device has an ATA Information VPD page. The assumption is that a SATL which is smart enough to implement WRITE SAME would also provide REPORT SUPPORTED OPERATION CODES. To facilitate the new heuristics scsi_report_opcode() has been modified to so we can distinguish between "operation not supported" and "RSOC not supported". Reported-by: H. Peter Anvin <hpa@zytor.com> Tested-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-11-14[SCSI] Add a report opcode helperMartin K. Petersen1-0/+45
The REPORT SUPPORTED OPERATION CODES command can be used to query whether a given opcode is supported by a device. Add a helper function that allows us to look up commands. We only issue RSOC if the device reports compliance with SPC-3 or later. But to err on the side of caution we disable the command for ATA, FireWire and USB. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-07-20[SCSI] async: make async_synchronize_full() flush all work regardless of domainDan Williams1-0/+1
In response to an async related regression James noted: "My theory is that this is an init problem: The assumption in a lot of our code is that async_synchronize_full() waits for everything ... even the domain specific async schedules, which isn't true." ...so make this assumption true. Each domain, including the default one, registers itself on a global domain list when work is scheduled. Once all entries complete it exits that list. Waiting for the list to be empty syncs all in-flight work across all domains. Domains can opt-out of global syncing if they are declared as exclusive ASYNC_DOMAIN_EXCLUSIVE(). All stack-based domains have been declared exclusive since the domain may go out of scope as soon as the last work item completes. Statically declared domains are mostly ok, but async_unregister_domain() is there to close any theoretical races with pending async_synchronize_full waiters at module removal time. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Reported-by: Meelis Roos <mroos@linux.ee> Reported-by: Eldad Zack <eldadzack@gmail.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-07-20[SCSI] async: introduce 'async_domain' typeDan Williams1-1/+2
This is in preparation for teaching async_synchronize_full() to sync all pending async work, and not just on the async_running domain. This conversion is functionally equivalent, just embedding the existing list in a new async_domain type. The .registered attribute is used in a later patch to distinguish between domains that want to be flushed by async_synchronize_full() versus those that only expect async_synchronize_{full|cookie}_domain to be used for flushing. [jejb: add async.h to scsi_priv.h for struct async_domain] Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-06-07[SCSI] Fix sd_probe_domain config problemJames Bottomley1-3/+1
With CONFIG_BLK_DEV_SD = n and CONFIG_PM = n, you get this compile failure: (.text+0x4f6c77): undefined reference to `scsi_sd_probe_domain' This was introduced by commit a7a20d103994fd760766e6c9d494daa569cbfe06 Author: Dan Williams <dan.j.williams@intel.com> Date: Thu Mar 22 17:05:11 2012 -0700 [SCSI] sd: limit the scope of the async probe domain And happens because scsi_sd_probe_domain is conditionally defined but unconditionally used. Fix this by making the symbol unconditionally defined. Reported-by: Randy Dunlap <rdunlap@xenotime.net> Cc: Dan Williams <dan.j.williams@intel.com> Tested-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-05-17[SCSI] sd: limit the scope of the async probe domainDan Williams1-0/+6
sd injects and synchronizes probe work on the global kernel-wide domain. This runs into conflict with PM that wants to perform resume actions in async context: [ 494.237079] INFO: task kworker/u:3:554 blocked for more than 120 seconds. [ 494.294396] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 494.360809] kworker/u:3 D 0000000000000000 0 554 2 0x00000000 [ 494.420739] ffff88012e4d3af0 0000000000000046 ffff88013200c160 ffff88012e4d3fd8 [ 494.484392] ffff88012e4d3fd8 0000000000012500 ffff8801394ea0b0 ffff88013200c160 [ 494.548038] ffff88012e4d3ae0 00000000000001e3 ffffffff81a249e0 ffff8801321c5398 [ 494.611685] Call Trace: [ 494.632649] [<ffffffff8149dd25>] schedule+0x5a/0x5c [ 494.674687] [<ffffffff8104b968>] async_synchronize_cookie_domain+0xb6/0x112 [ 494.734177] [<ffffffff810461ff>] ? __init_waitqueue_head+0x50/0x50 [ 494.787134] [<ffffffff8131a224>] ? scsi_remove_target+0x48/0x48 [ 494.837900] [<ffffffff8104b9d9>] async_synchronize_cookie+0x15/0x17 [ 494.891567] [<ffffffff8104ba49>] async_synchronize_full+0x54/0x70 <-- here we wait for async contexts to complete [ 494.943783] [<ffffffff8104b9f5>] ? async_synchronize_full_domain+0x1a/0x1a [ 495.002547] [<ffffffffa00114b1>] sd_remove+0x2c/0xa2 [sd_mod] [ 495.051861] [<ffffffff812fe94f>] __device_release_driver+0x86/0xcf [ 495.104807] [<ffffffff812fe9bd>] device_release_driver+0x25/0x32 <-- here we take device_lock() [ 853.511341] INFO: task kworker/u:4:549 blocked for more than 120 seconds. [ 853.568693] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 853.635119] kworker/u:4 D ffff88013097b5d0 0 549 2 0x00000000 [ 853.695129] ffff880132773c40 0000000000000046 ffff880130790000 ffff880132773fd8 [ 853.758990] ffff880132773fd8 0000000000012500 ffff88013288a0b0 ffff880130790000 [ 853.822796] 0000000000000246 0000000000000040 ffff88013097b5c8 ffff880130790000 [ 853.886633] Call Trace: [ 853.907631] [<ffffffff8149dd25>] schedule+0x5a/0x5c [ 853.949670] [<ffffffff8149cc44>] __mutex_lock_common+0x220/0x351 [ 854.001225] [<ffffffff81304bd7>] ? device_resume+0x58/0x1c4 [ 854.049082] [<ffffffff81304bd7>] ? device_resume+0x58/0x1c4 [ 854.097011] [<ffffffff8149ce48>] mutex_lock_nested+0x2f/0x36 <-- here we wait for device_lock() [ 854.145591] [<ffffffff81304bd7>] device_resume+0x58/0x1c4 [ 854.192066] [<ffffffff81304d61>] async_resume+0x1e/0x45 [ 854.237019] [<ffffffff8104bc93>] async_run_entry_fn+0xc6/0x173 <-- ...while running in async context Provide a 'scsi_sd_probe_domain' so that async probe actions actions can be flushed without regard for the state of PM, and allow for the resume path to handle devices that have transitioned from SDEV_QUIESCE to SDEV_DEL prior to resume. Acked-by: Alan Stern <stern@rowland.harvard.edu> [alan: uplevel scsi_sd_probe_domain, clarify scsi_device_resume] Signed-off-by: Dan Williams <dan.j.williams@intel.com> [jejb: remove unneeded config guards in include file] Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-02-19[SCSI] Handle disk devices which can not process medium access commandsMartin K. Petersen1-6/+0
We have experienced several devices which fail in a fashion we do not currently handle gracefully in SCSI. After a failure these devices will respond to the SCSI primary command set (INQUIRY, TEST UNIT READY, etc.) but any command accessing the storage medium will time out. The following patch adds an callback that can be used by upper level drivers to inspect the results of an error handling command. This in turn has been used to implement additional checking in the SCSI disk driver. If a medium access command fails twice but TEST UNIT READY succeeds both times in the subsequent error handling we will offline the device. The maximum number of failed commands required to take a device offline can be tweaked in sysfs. Also add a new error flag to scsi_debug which allows this scenario to be easily reproduced. [jejb: fix up integer parsing to use kstrtouint] Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2010-11-17SCSI host lock push-downJeff Garzik1-13/+5
Move the mid-layer's ->queuecommand() invocation from being locked with the host lock to being unlocked to facilitate speeding up the critical path for drivers who don't need this lock taken anyway. The patch below presents a simple SCSI host lock push-down as an equivalent transformation. No locking or other behavior should change with this patch. All existing bugs and locking orders are preserved. Additionally, add one parameter to queuecommand, struct Scsi_Host * and remove one parameter from queuecommand, void (*done)(struct scsi_cmnd *) Scsi_Host* is a convenient pointer that most host drivers need anyway, and 'done' is redundant to struct scsi_cmnd->scsi_done. Minimal code disturbance was attempted with this change. Most drivers needed only two one-line modifications for their host lock push-down. Signed-off-by: Jeff Garzik <jgarzik@redhat.com> Acked-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-16[SCSI] Fix VPD inquiry page wrapperMartin K. Petersen1-2/+2
Fix two bugs in the VPD page wrapper: - Don't return failure if the user asked for page 0 - The end of buffer check failed to account for the page header size and consequently didn't work Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Cc: Stable Tree <stable@kernel.org> Signed-off-by: James Bottomley <James.Bottomley@suse.de>