kernel/linux.git/drivers/scsi/scsi_debug.c, branch v6.6.133

scsi: scsi_debug: Fix hrtimer support for ndelay

2024-12-14T18:59:49+00:00

[ Upstream commit 6918141d815acef056a0d10e966a027d869a922d ] Since commit 771f712ba5b0 ("scsi: scsi_debug: Fix cmd duration calculation"), ns_from_boot value is only evaluated in schedule_resp() for polled requests. However, ns_from_boot is also required for hrtimer support for when ndelay is less than INCLUSIVE_TIMING_MAX_NS, so fix up the logic to decide when to evaluate ns_from_boot. Fixes: 771f712ba5b0 ("scsi: scsi_debug: Fix cmd duration calculation") Signed-off-by: John Garry Link: https://lore.kernel.org/r/20241202130045.2335194-1-john.g.garry@oracle.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: scsi_debug: Remove dead code

2023-07-06T01:37:43+00:00

The ramdisk rwlocks are not used anymore. Fixes: 87c715dcde63 ("scsi: scsi_debug: Add per_host_store option") Signed-off-by: Maurizio Lombardi Link: https://lore.kernel.org/r/20230628150638.53218-1-mlombard@redhat.com Reviewed-by: Laurence Oberman Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Abort commands from scsi_debug_device_reset()

2023-04-19T02:58:50+00:00

Currently scsi_debug_device_reset() does not do much apart from setting the SDEBUG_UA_POR ("Power on, reset, or bus device reset") flag, which is eventually passed back to the SCSI midlayer later for a "unit attention" command. There is a report that blktest scsi/007 test fails due to commit 1107c7b24ee3 ("scsi: scsi_debug: Dynamically allocate sdebug_queued_cmd"). The problem there is that there are dangling scsi_debug queued commands when we attempt to remove the driver. scsi/007 test triggers SCSI EH and attempts to abort a timed-out command. Function scsi_debug_device_reset() is called as part of the EH, but does not deal with outstanding erroneous command. Prior to the named commit, removing the driver caused all dangling queued commands to be stopped - this should have not been necessary. Fix by aborting outstanding commands on a scsi_device basis from scsi_debug_device_reset(). Fixes: 1107c7b24ee3 ("scsi: scsi_debug: Dynamically allocate sdebug_queued_cmd") Reported-by: kernel test robot Link: https://lore.kernel.org/oe-lkp/202304071111.e762fcbd-yujie.liu@intel.com Signed-off-by: John Garry Link: https://lore.kernel.org/r/20230416175654.159163-1-john.g.garry@oracle.com Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Fix missing error code in scsi_debug_init()

2023-04-12T01:15:00+00:00

Smatch reports: drivers/scsi/scsi_debug.c:6996 scsi_debug_init() warn: missing error code 'ret' Although it is unlikely that KMEM_CACHE might fail, but if it does then ret might be zero. So to fix this explicitly mark ret as "-ENOMEM" and then goto driver_unreg. Fixes: 1107c7b24ee3 ("scsi: scsi_debug: Dynamically allocate sdebug_queued_cmd") Signed-off-by: Harshit Mogalapalli Link: https://lore.kernel.org/r/20230406074607.3637097-1-harshit.m.mogalapalli@oracle.com Reviewed-by: John Garry Signed-off-by: Martin K. Petersen

Merge patch series "Fix shost command overloading issues"

2023-04-03T02:10:40+00:00

John Garry says: It's easy to get scsi_debug to error on throughput testing when we have multiple shosts: $ lsscsi [7:0:0:0] disk Linux scsi_debug 0191 [0:0:0:0] disk Linux scsi_debug 0191 $ fio --filename=/dev/sda --filename=/dev/sdb --direct=1 --rw=read --bs=4k --iodepth=256 --runtime=60 --numjobs=40 --time_based --name=jpg --eta-newline=1 --readonly --ioengine=io_uring --hipri --exitall_on_error jpg: (g=0): rw=read, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=256 ... fio-3.28 Starting 40 processes [ 27.521809] hrtimer: interrupt took 33067 ns [ 27.904660] sd 7:0:0:0: [sdb] tag#171 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s [ 27.904660] sd 0:0:0:0: [sda] tag#58 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s fio: io_u error [ 27.904667] sd 0:0:0:0: [sda] tag#58 CDB: Read(10) 28 00 00 00 27 00 00 01 18 00 on file /dev/sda[ 27.904670] sd 0:0:0:0: [sda] tag#62 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s The issue is related to how the driver manages submit queues and tags. A single array of submit queues - sdebug_q_arr - with its own set of tags is shared among all shosts. As such, for occasions when we have more than one host it is possible to overload the submit queues and run out of tags. Another separate issue that we may reduce the shost submit queue depth, sdebug_max_queue, dynamically causing the shost to be overloaded. How many IOs which the shost may be sent is fixed at can_queue at init time, which is the same initial value for sdebug_max_queue. So reducing sdebug_max_queue means that the shost may be sent more IOs than it is configured to handle, causing overloading. This series removes the scsi_debug submit queue concept and uses pre-existing APIs to manage and examine tags, like scsi_block_requests() and blk_mq_tagset_busy_iter(). Using standard APIs makes the driver more maintainable and extensible in future. A restriction is also added to allow sdebug_max_queue only be modified when no shosts are present, i.e. we need to remove shosts, modify sdebug_max_queue, and then re-add the shosts. Link: https://lore.kernel.org/r/20230327074310.1862889-1-john.g.garry@oracle.com Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Drop sdebug_queue

2023-04-03T02:09:22+00:00

It's easy to get scsi_debug to error on throughput testing when we have multiple shosts: $ lsscsi [7:0:0:0] disk Linux scsi_debug 0191 [0:0:0:0] disk Linux scsi_debug 0191 $ fio --filename=/dev/sda --filename=/dev/sdb --direct=1 --rw=read --bs=4k --iodepth=256 --runtime=60 --numjobs=40 --time_based --name=jpg --eta-newline=1 --readonly --ioengine=io_uring --hipri --exitall_on_error jpg: (g=0): rw=read, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=256 ... fio-3.28 Starting 40 processes [ 27.521809] hrtimer: interrupt took 33067 ns [ 27.904660] sd 7:0:0:0: [sdb] tag#171 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s [ 27.904660] sd 0:0:0:0: [sda] tag#58 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s fio: io_u error [ 27.904667] sd 0:0:0:0: [sda] tag#58 CDB: Read(10) 28 00 00 00 27 00 00 01 18 00 on file /dev/sda[ 27.904670] sd 0:0:0:0: [sda] tag#62 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s The issue is related to how the driver manages submit queues and tags. A single array of submit queues - sdebug_q_arr - with its own set of tags is shared among all shosts. As such, for occasions when we have more than one shost it is possible to overload the submit queues and run out of tags. The struct sdebug_queue is to manage tags and hold the associated queued command entry pointer (for that tag). Since the tagset iters are now used for functions like sdebug_blk_mq_poll(), there is no need to manage these queues. Indeed, blk-mq already provides what we need for managing tags and queues. Drop sdebug_queue and all its usage in the driver. Signed-off-by: John Garry Link: https://lore.kernel.org/r/20230327074310.1862889-12-john.g.garry@oracle.com Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Only allow sdebug_max_queue be modified when no shosts

2023-04-03T02:09:22+00:00

The shost->can_queue value is initially used to set per-HW queue context tag depth in the block layer. This ensures that the shost is not sent too many commands which it can deal with. However lowering sdebug_max_queue separately means that we can easily overload the shost, as in the following example: $ cat /sys/bus/pseudo/drivers/scsi_debug/max_queue 192 $ cat /sys/class/scsi_host/host0/can_queue 192 $ echo 100 > /sys/bus/pseudo/drivers/scsi_debug/max_queue $ cat /sys/class/scsi_host/host0/can_queue 192 $ fio --filename=/dev/sda --direct=1 --rw=read --bs=4k --iodepth=256 --runtime=1200 --numjobs=10 --time_based --group_reporting --name=iops-test-job --eta-newline=1 --readonly --ioengine=io_uring --hipri --exitall_on_error iops-test-job: (g=0): rw=read, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=256 ... fio-3.28 Starting 10 processes [ 111.269885] scsi_io_completion_action: 400 callbacks suppressed [ 111.269885] blk_print_req_error: 400 callbacks suppressed [ 111.269889] I/O error, dev sda, sector 440 op 0x0:(READ) flags 0x1200000 phys_seg 1 prio class 2 [ 111.269892] sd 0:0:0:0: [sda] tag#132 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s [ 111.269897] sd 0:0:0:0: [sda] tag#132 CDB: Read(10) 28 00 00 00 01 68 00 00 08 00 [ 111.277058] I/O error, dev sda, sector 360 op 0x0:(READ) flags 0x1200000 phys_seg 1 prio class 2 [...] Ensure that this cannot happen by allowing sdebug_max_queue be modified only when we have no shosts. As such, any shost->can_queue value will match sdebug_max_queue, and sdebug_max_queue cannot be modified separately. Since retired_max_queue is no longer set, remove support. Continue to apply the restriction that sdebug_host_max_queue cannot be modified when sdebug_host_max_queue is set. Adding support for that would mean extra code, and no one has complained about this restriction previously. A command like the following may be used to remove a shost: echo -1 > /sys/bus/pseudo/drivers/scsi_debug/add_host Signed-off-by: John Garry Link: https://lore.kernel.org/r/20230327074310.1862889-11-john.g.garry@oracle.com Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Use scsi_host_busy() in delay_store() and ndelay_store()

2023-04-03T02:09:22+00:00

The functions to update ndelay and delay value first check whether we have any in-flight IO for any host. It does this by checking if any tag is used in the global submit queues. We can achieve the same by setting the host as blocked and then ensuring that we have no in-flight commands with scsi_host_busy(). Note that scsi_host_busy() checks SCMD_STATE_INFLIGHT flag, which is only set per command after we ensure that the host is not blocked, i.e. we see more commands active after the check for scsi_host_busy() returns 0. Signed-off-by: John Garry Link: https://lore.kernel.org/r/20230327074310.1862889-10-john.g.garry@oracle.com Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Use blk_mq_tagset_busy_iter() in stop_all_queued()

2023-04-03T02:09:22+00:00

Instead of iterating all deferred commands in the submission queue structures, use blk_mq_tagset_busy_iter(), which is a standard API for this. Signed-off-by: John Garry Link: https://lore.kernel.org/r/20230327074310.1862889-9-john.g.garry@oracle.com Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Use blk_mq_tagset_busy_iter() in sdebug_blk_mq_poll()

2023-04-03T02:09:22+00:00

Instead of iterating all deferred commands in the submission queue structures, use blk_mq_tagset_busy_iter(), which is a standard API for this. Signed-off-by: John Garry Link: https://lore.kernel.org/r/20230327074310.1862889-8-john.g.garry@oracle.com Signed-off-by: Martin K. Petersen