- 01 10月, 2015 1 次提交
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由 Christoph Hellwig 提交于
blk_mq_complete_request may be a no-op if the request has already been completed by others means (e.g. a timeout or cancellation), but currently drivers have to set rq->errors before calling blk_mq_complete_request, which might leave us with the wrong error value. Add an error parameter to blk_mq_complete_request so that we can defer setting rq->errors until we known we won the race to complete the request. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NSagi Grimberg <sagig@mellanox.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 29 8月, 2015 1 次提交
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由 Christoph Hellwig 提交于
Add a ->handler and a ->handler_data field to struct scsi_device and kill this indirection. Also move struct scsi_device_handler to scsi_dh.h so that changes to it don't require rebuilding every SCSI LLDD. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> Reviewed-by: NHannes Reinecke <hare@suse.de> Signed-off-by: NJames Bottomley <JBottomley@Odin.com>
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- 26 8月, 2015 1 次提交
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由 Hannes Reinecke 提交于
Log the ALUA state change unit attention correctly with the message log and emit an event to allow user-space tools to react to it. Signed-off-by: NHannes Reinecke <hare@suse.de> Reviewed-by: NEwan D. Milne <emilne@redhat.com> Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: NJames Bottomley <JBottomley@Odin.com>
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- 31 7月, 2015 2 次提交
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由 Hannes Reinecke 提交于
The 'sd' driver is calling scsi_mode_sense() to figure out internal details. But scsi_mode_sense() never checks for any pending unit attentions, so we're getting annoying error messages like: MODE SENSE: unimplemented page/subpage: 0x00/0x00 and a possible wrong decision for device cache handling. Reviewed-by: NEwan Milne <emilne@redhat.com> Signed-off-by: NHannes Reinecke <hare@suse.de> Signed-off-by: NJames Bottomley <JBottomley@Odin.com>
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由 Tony Battersby 提交于
Fix a memory leak with scsi-mq triggered by commands with large data transfer length. __sg_alloc_table() sets both table->nents and table->orig_nents to the same value. When the scatterlist is DMA-mapped, table->nents is overwritten with the (possibly smaller) size of the DMA-mapped scatterlist, while table->orig_nents retains the original size of the allocated scatterlist. scsi_free_sgtable() should therefore check orig_nents instead of nents, and all code that initializes sdb->table without calling __sg_alloc_table() should set both nents and orig_nents. Fixes: d285203c ("scsi: add support for a blk-mq based I/O path.") Cc: <stable@vger.kernel.org> # 3.17+ Signed-off-by: NTony Battersby <tonyb@cybernetics.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NEwan D. Milne <emilne@redhat.com> Signed-off-by: NJames Bottomley <JBottomley@Odin.com>
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- 09 4月, 2015 1 次提交
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由 Bart Van Assche 提交于
SCSI transport drivers and SCSI LLDs block a SCSI device if the transport layer is not operational. This means that in this state no requests should be processed, even if the REQ_PREEMPT flag has been set. This patch avoids that a rescan shortly after a cable pull sporadically triggers the following kernel oops: BUG: unable to handle kernel paging request at ffffc9001a6bc084 IP: [<ffffffffa04e08f2>] mlx4_ib_post_send+0xd2/0xb30 [mlx4_ib] Process rescan-scsi-bus (pid: 9241, threadinfo ffff88053484a000, task ffff880534aae100) Call Trace: [<ffffffffa0718135>] srp_post_send+0x65/0x70 [ib_srp] [<ffffffffa071b9df>] srp_queuecommand+0x1cf/0x3e0 [ib_srp] [<ffffffffa0001ff1>] scsi_dispatch_cmd+0x101/0x280 [scsi_mod] [<ffffffffa0009ad1>] scsi_request_fn+0x411/0x4d0 [scsi_mod] [<ffffffff81223b37>] __blk_run_queue+0x27/0x30 [<ffffffff8122a8d2>] blk_execute_rq_nowait+0x82/0x110 [<ffffffff8122a9c2>] blk_execute_rq+0x62/0xf0 [<ffffffffa000b0e8>] scsi_execute+0xe8/0x190 [scsi_mod] [<ffffffffa000b2f3>] scsi_execute_req+0xa3/0x130 [scsi_mod] [<ffffffffa000c1aa>] scsi_probe_lun+0x17a/0x450 [scsi_mod] [<ffffffffa000ce86>] scsi_probe_and_add_lun+0x156/0x480 [scsi_mod] [<ffffffffa000dc2f>] __scsi_scan_target+0xdf/0x1f0 [scsi_mod] [<ffffffffa000dfa3>] scsi_scan_host_selected+0x183/0x1c0 [scsi_mod] [<ffffffffa000edfb>] scsi_scan+0xdb/0xe0 [scsi_mod] [<ffffffffa000ee13>] store_scan+0x13/0x20 [scsi_mod] [<ffffffff811c8d9b>] sysfs_write_file+0xcb/0x160 [<ffffffff811589de>] vfs_write+0xce/0x140 [<ffffffff81158b53>] sys_write+0x53/0xa0 [<ffffffff81464592>] system_call_fastpath+0x16/0x1b [<00007f611c9d9300>] 0x7f611c9d92ff Reported-by: NMax Gurtuvoy <maxg@mellanox.com> Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: NMike Christie <michaelc@cs.wisc.edu> Cc: <stable@vger.kernel.org> Signed-off-by: NJames Bottomley <JBottomley@Odin.com>
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- 24 1月, 2015 1 次提交
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由 Shaohua Li 提交于
This is the blk-mq part to support tag allocation policy. The default allocation policy isn't changed (though it's not a strict FIFO). The new policy is round-robin for libata. But it's a try-best implementation. If multiple tasks are competing, the tags returned will be mixed (which is unavoidable even with !mq, as requests from different tasks can be mixed in queue) Cc: Jens Axboe <axboe@fb.com> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: NShaohua Li <shli@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 20 1月, 2015 1 次提交
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由 Ewan D. Milne 提交于
This can happen if a multipathed device uses DIX and another path is added via an adapter that does not support it. Multipath should not allow this path to be added, but we should not depend upon that to avoid crashing. Signed-off-by: NEwan D. Milne <emilne@redhat.com> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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- 09 1月, 2015 1 次提交
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由 Christoph Hellwig 提交于
The blk-mq ->queue_rq method is always called from process context, but might have preemption disabled. This means we still always have to use GFP_ATOMIC for memory allocations, and thus need to revert part of commit 3c356bde ("scsi: stop passing a gfp_mask argument down the command setup path"). Signed-off-by: NChristoph Hellwig <hch@lst.de> Reported-by: NSasha Levin <sasha.levin@oracle.com> Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com> Tested-by: NAlexei Starovoitov <alexei.starovoitov@gmail.com>
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- 15 12月, 2014 1 次提交
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由 Tony Battersby 提交于
This fixes random memory corruption triggered when all three of the following are true: * scsi-mq enabled * T10 Protection Information (DIF) enabled * SCSI host with sg_tablesize > SCSI_MAX_SG_SEGMENTS (128) The symptoms of this bug are unpredictable memory corruption, BUG()s, oopses, lockups, etc., any of which may appear to be completely unrelated to the root cause. Cc: <stable@vger.kernel.org> # 3.17.x, 3.18.x Signed-off-by: NTony Battersby <tonyb@cybernetics.com> Reviewed-by: NNicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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- 25 11月, 2014 3 次提交
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由 Christoph Hellwig 提交于
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: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBart Van Assche <bvanassche@acm.org> Reviewed-by: NHannes Reinecke <hare@suse.de>
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由 Christoph Hellwig 提交于
There is no reason for ULDs to pass in a flag on how to allocate the S/G lists. While we don't need GFP_ATOMIC for the blk-mq case because we don't hold locks, that decision can be made way down the chain without having to pass a pointless gfp_mask argument. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBart Van Assche <bvanassche@acm.org> Reviewed-by: NHannes Reinecke <hare@suse.de>
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由 Christoph Hellwig 提交于
There's only one caller left, so inline it and reduce the blk-mq vs !blk-mq diff a litte bit. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBart Van Assche <bvanassche@acm.org> Reviewed-by: NHannes Reinecke <hare@suse.de>
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- 12 11月, 2014 7 次提交
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由 Christoph Hellwig 提交于
Currently scsi piggy backs on the block layer to define the concept of a tagged command. But we want to be able to have block-level host-wide tags assigned even for untagged commands like the initial INQUIRY, so add a new SCSI-level flag for commands that are tagged at the scsi level, so that even commands without that set can have tags assigned to them. Note that this alredy is the case for the blk-mq code path, and this just lets the old path catch up with it. We also set this flag based upon sdev->simple_tags instead of the block queue flag, so that it is entirely independent of the block layer tagging, and thus always correct even if a driver doesn't use block level tagging yet. Also remove the old blk_rq_tagged; it was only used by SCSI drivers, and removing it forces them to look for the proper replacement. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NMike Christie <michaelc@cs.wisc.edu> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> Reviewed-by: NHannes Reinecke <hare@suse.de>
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由 Bart Van Assche 提交于
Allow a SCSI LLD to declare how many hardware queues it supports by setting Scsi_Host.nr_hw_queues before calling scsi_add_host(). Signed-off-by: NBart Van Assche <bvanassche@acm.org> Reviewed-by: NSagi Grimberg <sagig@mellanox.com> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Hannes Reinecke 提交于
There can be quite a lot of I/O error messages, even on smaller machines. So we need to ratelimit them to not overwhelm logging. Signed-off-by: NHannes Reinecke <hare@suse.de> Tested-by: NRobert Elliott <elliott@hp.com> Reviewed-by: NRobert Elliott <elliott@hp.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Hannes Reinecke 提交于
Simplify scsi_log_(send|completion) by externalizing scsi_mlreturn_string() and always print the command address. Signed-off-by: NHannes Reinecke <hare@suse.de> Reviewed-by: NRobert Elliott <elliott@hp.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Hannes Reinecke 提交于
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>
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由 Hannes Reinecke 提交于
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>
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由 Mark Rustad 提交于
Resolve some missing-field-initializers warnings by using designated initialization. [hch: W=2 with modern gcc warns about this. Pretty pointless to me, but I'd prefer to keep us warning free] Signed-off-by: NMark Rustad <mark.d.rustad@intel.com> Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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- 30 10月, 2014 1 次提交
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由 Jens Axboe 提交于
Since we have the notion of a 'last' request in a chain, we can use this to have the hardware optimize the issuing of requests. Add a list_head parameter to queue_rq that the driver can use to temporarily store hw commands for issue when 'last' is true. If we are doing a chain of requests, pass in a NULL list for the first request to force issue of that immediately, then batch the remainder for deferred issue until the last request has been sent. Instead of adding yet another argument to the hot ->queue_rq path, encapsulate the passed arguments in a blk_mq_queue_data structure. This is passed as a constant, and has been tested as faster than passing 4 (or even 3) args through ->queue_rq. Update drivers for the new ->queue_rq() prototype. There are no functional changes in this patch for drivers - if they don't use the passed in list, then they will just queue requests individually like before. Signed-off-by: NJens Axboe <axboe@fb.com>
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- 28 10月, 2014 1 次提交
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由 Christoph Hellwig 提交于
To generate the right SPI tag messages we need to properly set QUEUE_FLAG_QUEUED in the request_queue and mirror it to the request. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> Acked-by: NJens Axboe <axboe@kernel.dk> Reported-by: NMeelis Roos <mroos@linux.ee> Tested-by: NMeelis Roos <mroos@linux.ee> Cc: stable@vger.kernel.org
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- 23 9月, 2014 5 次提交
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由 Christoph Hellwig 提交于
Some ATA drivers need the dma drain size workaround, and thus need to call blk_mq_start_request before the S/G mapping. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Christoph Hellwig 提交于
Allow blk-mq to pass an argument to the timeout handler to indicate if we're timing out a reserved or regular command. For many drivers those need to be handled different. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Christoph Hellwig 提交于
Now that we've changed the driver API on the submission side use the opportunity to fix up the name on the completion side to fit into the general scheme. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Christoph Hellwig 提交于
When we call blk_mq_start_request from the core blk-mq code before calling into ->queue_rq there is a racy window where the timeout handler can hit before we've fully set up the driver specific part of the command. Move the call to blk_mq_start_request into the driver so the driver can start the request only once it is fully set up. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Christoph Hellwig 提交于
Pass an explicit parameter for the last request in a batch to ->queue_rq instead of using a request flag. Besides being a cleaner and non-stateful interface this is also required for the next patch, which fixes the blk-mq I/O submission code to not start a time too early. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 19 9月, 2014 1 次提交
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由 Daniel Gryniewicz 提交于
When ending a bi-directionional SCSI request, blk_finish_request() cleans up and frees the request, but scsi_release_bidi_buffers() tries to indirect through the request to find it's data buffers. This causes a panic due to a null pointer dereference. Move the call to scsi_release_bidi_buffers() before the call to blk_finish_request(). Signed-off-by: NDaniel Gryniewicz <dang@linuxbox.com> Reviewed-by: NWebb Scales <webbnh@hp.com> Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>
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- 16 9月, 2014 1 次提交
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Add a use_cmd_list flag in struct Scsi_Host to request keeping track of all outstanding commands per device. Default behaviour is not to keep track of cmd_list per sdev, as this may introduce lock contention. (overhead is more on multi-node NUMA.), and only enable it on the two drivers that need it. Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> Reviewed-by: NBart Van Assche <bvanassche@acm.org> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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- 29 8月, 2014 1 次提交
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由 Joe Lawrence 提交于
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>
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- 23 8月, 2014 1 次提交
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由 Tony Battersby 提交于
This patch fixes code such as the following with scsi-mq enabled: rq = blk_get_request(...); blk_rq_set_block_pc(rq); rq->cmd = my_cmd_buffer; /* separate CDB buffer */ blk_execute_rq_nowait(...); Code like this appears in e.g. sg_start_req() in drivers/scsi/sg.c (for large CDBs only). Without this patch, scsi_mq_prep_fn() will set rq->cmd back to rq->__cmd, causing the wrong CDB to be sent to the device. Signed-off-by: NTony Battersby <tonyb@cybernetics.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 20 8月, 2014 1 次提交
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由 Guenter Roeck 提交于
The latest kernel fails to boot qemu arm images when using scsi for disk access. Boot gets stuck after the following messages. brd: module loaded sym53c8xx 0000:00:0c.0: enabling device (0100 -> 0103) sym0: <895a> rev 0x0 at pci 0000:00:0c.0 irq 93 sym0: No NVRAM, ID 7, Fast-40, LVD, parity checking sym0: SCSI BUS has been reset. scsi host0: sym-2.2.3 Bisect points to commit 71e75c97 ("scsi: convert device_busy to atomic_t"). Code inspection shows the following suspicious change in scsi_request_fn. out_delay: - if (sdev->device_busy == 0 && !scsi_device_blocked(sdev)) + if (atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev)) blk_delay_queue(q, SCSI_QUEUE_DELAY); } 'sdev->device_busy == 0' was replaced with 'atomic_read(&sdev->device_busy)', meaning the logic was reversed. Changing this expression to '!atomic_read(&sdev->device_busy)' fixes the problem. Signed-off-by: NGuenter Roeck <linux@roeck-us.net> Reviewed-by: NHannes Reinecke <hare@suse.de> Acked-by: NJens Axboe <axboe@fb.com> Reviewed-by: NVenkatesh Srinivas <venkateshs@google.com> Reviewed-by: NWebb Scales <webbnh@hp.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 8月, 2014 1 次提交
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由 Guenter Roeck 提交于
The latest kernel fails to boot qemu arm images when using scsi for disk access. Boot gets stuck after the following messages. brd: module loaded sym53c8xx 0000:00:0c.0: enabling device (0100 -> 0103) sym0: <895a> rev 0x0 at pci 0000:00:0c.0 irq 93 sym0: No NVRAM, ID 7, Fast-40, LVD, parity checking sym0: SCSI BUS has been reset. scsi host0: sym-2.2.3 Bisect points to commit 71e75c97 ("scsi: convert device_busy to atomic_t"). Code inspection shows the following suspicious change in scsi_request_fn. out_delay: - if (sdev->device_busy == 0 && !scsi_device_blocked(sdev)) + if (atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev)) blk_delay_queue(q, SCSI_QUEUE_DELAY); } 'sdev->device_busy == 0' was replaced with 'atomic_read(&sdev->device_busy)', meaning the logic was reversed. Changing this expression to '!atomic_read(&sdev->device_busy)' fixes the problem. Signed-off-by: NGuenter Roeck <linux@roeck-us.net> Reviewed-by: NHannes Reinecke <hare@suse.de> Acked-by: NJens Axboe <axboe@fb.com> Signed-off-by: NChristoph Hellwig <hch@lst.de> Fixes: 71e75c97Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>
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- 26 7月, 2014 5 次提交
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由 Christoph Hellwig 提交于
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: 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>
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由 Christoph Hellwig 提交于
Blk-mq drivers usually preallocate their S/G list as part of the request, but if we want to support the very large S/G lists currently supported by the SCSI code that would tie up a lot of memory in the preallocated request pool. Add support to the scatterlist code so that it can initialize a S/G list that uses a preallocated first chunks and dynamically allocated additional chunks. That way the scsi-mq code can preallocate a first page worth of S/G entries as part of the request, and dynamically extend the S/G list when needed. 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>
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由 Christoph Hellwig 提交于
Replace the calls to the various blk_end_request variants with opencode equivalents. Blk-mq is using a model that gives the driver control between the bio updates and the actual completion, and making the old code follow that same model allows us to keep the code more similar for both paths. 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>
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由 Christoph Hellwig 提交于
This saves us an atomic operation for each I/O submission and completion for the usual case where the driver doesn't set a per-target can_queue value. Only a few iscsi hardware offload drivers set the per-target can_queue value at the moment. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> 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>
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由 Christoph Hellwig 提交于
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: NChristoph Hellwig <hch@lst.de> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> 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>
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- 25 7月, 2014 2 次提交
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由 Christoph Hellwig 提交于
Avoid taking the queue_lock to check the per-device 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. Unlike the host and target busy counters this doesn't allow us to avoid the queue_lock in the request_fn due to the way the interface works, but it'll allow us to prepare for using the blk-mq code, which doesn't use the queue_lock at all, and it at least avoids a queue_lock round trip in scsi_device_unbusy, which is still important given how busy the queue_lock is. Signed-off-by: NChristoph Hellwig <hch@lst.de> 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>
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由 Christoph Hellwig 提交于
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>
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