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| author | Uma Krishnan <ukrishn@linux.vnet.ibm.com> | 2018-05-11 22:04:46 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2018-05-18 18:22:09 +0300 |
| commit | e0f76ad13085b730091256d7a2fbe3555f0686df (patch) | |
| tree | ff6b5ef200605aa31ba0f54e16a5fed2d3320524 /drivers/scsi/cxlflash | |
| parent | 2f6bca202b78e2b63a62b46ff5dc26f300785e23 (diff) | |
| download | linux-e0f76ad13085b730091256d7a2fbe3555f0686df.tar.xz | |
scsi: cxlflash: Yield to active send threads
The following Oops may be encountered if the device is reset, i.e. EEH
recovery, while there is heavy I/O traffic:
59:mon> t
[c000200db64bb680] c008000009264c40 cxlflash_queuecommand+0x3b8/0x500
[cxlflash]
[c000200db64bb770] c00000000090d3b0 scsi_dispatch_cmd+0x130/0x2f0
[c000200db64bb7f0] c00000000090fdd8 scsi_request_fn+0x3c8/0x8d0
[c000200db64bb900] c00000000067f528 __blk_run_queue+0x68/0xb0
[c000200db64bb930] c00000000067ab80 __elv_add_request+0x140/0x3c0
[c000200db64bb9b0] c00000000068daac blk_execute_rq_nowait+0xec/0x1a0
[c000200db64bba00] c00000000068dbb0 blk_execute_rq+0x50/0xe0
[c000200db64bba50] c0000000006b2040 sg_io+0x1f0/0x520
[c000200db64bbaf0] c0000000006b2e94 scsi_cmd_ioctl+0x534/0x610
[c000200db64bbc20] c000000000926208 sd_ioctl+0x118/0x280
[c000200db64bbcc0] c00000000069f7ac blkdev_ioctl+0x7fc/0xe30
[c000200db64bbd20] c000000000439204 block_ioctl+0x84/0xa0
[c000200db64bbd40] c0000000003f8514 do_vfs_ioctl+0xd4/0xa00
[c000200db64bbde0] c0000000003f8f04 SyS_ioctl+0xc4/0x130
[c000200db64bbe30] c00000000000b184 system_call+0x58/0x6c
When there is no room to send the I/O request, the cached room is refreshed
by reading the memory mapped command room value from the AFU. The AFU
register mapping is refreshed during a reset, creating a race condition that
can lead to the Oops above.
During a device reset, the AFU should not be unmapped until all the active
send threads quiesce. An atomic counter, cmds_active, is currently used to
track internal AFU commands and quiesce during reset. This same counter can
also be used for the active send threads.
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/cxlflash')
| -rw-r--r-- | drivers/scsi/cxlflash/main.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index a24d7e6e51c1..dad2be6c29c3 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -616,6 +616,7 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp) rc = 0; goto out; default: + atomic_inc(&afu->cmds_active); break; } @@ -641,6 +642,7 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp) memcpy(cmd->rcb.cdb, scp->cmnd, sizeof(cmd->rcb.cdb)); rc = afu->send_cmd(afu, cmd); + atomic_dec(&afu->cmds_active); out: return rc; } |