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authorBart Van Assche <bart.vanassche@wdc.com>2017-10-20 11:46:45 -0700
committerMartin K. Petersen <martin.petersen@oracle.com>2017-10-23 04:19:45 -0400
commit8fe8ffb12c81b36877984274db184953c337db73 (patch)
tree3437ca4c6c036056141802352ae4a2abbc82f50e /drivers/scsi/scsi_lib.c
parent587c3c9f286cee5c9cac38d28c8ae1875f4ec85b (diff)
scsi: Suppress a kernel warning in case the prep function returns BLKPREP_DEFER
The legacy block layer handles requests as follows: - If the prep function returns BLKPREP_OK, let blk_peek_request() return the pointer to that request. - If the prep function returns BLKPREP_DEFER, keep the RQF_STARTED flag and retry calling the prep function later. - If the prep function returns BLKPREP_KILL or BLKPREP_INVALID, end the request. In none of these cases it is correct to clear the SCMD_INITIALIZED flag from inside scsi_prep_fn(). Since scsi_prep_fn() already guarantees that scsi_init_command() will be called once even if scsi_prep_fn() is called multiple times, remove the code that clears SCMD_INITIALIZED from scsi_prep_fn(). The scsi-mq code handles requests as follows: - If scsi_mq_prep_fn() returns BLKPREP_OK, set the RQF_DONTPREP flag and submit the request to the SCSI LLD. - If scsi_mq_prep_fn() returns BLKPREP_DEFER, call blk_mq_delay_run_hw_queue() and return BLK_STS_RESOURCE. - If the prep function returns BLKPREP_KILL or BLKPREP_INVALID, call scsi_mq_uninit_cmd() and let the blk-mq core end the request. In none of these cases scsi_mq_prep_fn() should clear the SCMD_INITIALIZED flag. Hence remove the code from scsi_mq_prep_fn() function that clears that flag. This patch avoids that the following warning is triggered when using the legacy block layer: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 4198 at drivers/scsi/scsi_lib.c:654 scsi_end_request+0x1de/0x220 CPU: 1 PID: 4198 Comm: mkfs.f2fs Not tainted 4.14.0-rc5+ #1 task: ffff91c147a4b800 task.stack: ffffb282c37b8000 RIP: 0010:scsi_end_request+0x1de/0x220 Call Trace: <IRQ> scsi_io_completion+0x204/0x5e0 scsi_finish_command+0xce/0xe0 scsi_softirq_done+0x126/0x130 blk_done_softirq+0x6e/0x80 __do_softirq+0xcf/0x2a8 irq_exit+0xab/0xb0 do_IRQ+0x7b/0xc0 common_interrupt+0x90/0x90 </IRQ> RIP: 0010:_raw_spin_unlock_irqrestore+0x9/0x10 __test_set_page_writeback+0xc7/0x2c0 __block_write_full_page+0x158/0x3b0 block_write_full_page+0xc4/0xd0 blkdev_writepage+0x13/0x20 __writepage+0x12/0x40 write_cache_pages+0x204/0x500 generic_writepages+0x48/0x70 blkdev_writepages+0x9/0x10 do_writepages+0x34/0xc0 __filemap_fdatawrite_range+0x6c/0x90 file_write_and_wait_range+0x31/0x90 blkdev_fsync+0x16/0x40 vfs_fsync_range+0x44/0xa0 do_fsync+0x38/0x60 SyS_fsync+0xb/0x10 entry_SYSCALL_64_fastpath+0x13/0x94 ---[ end trace 86e8ef85a4a6c1d1 ]--- Fixes: commit 64104f703212 ("scsi: Call scsi_initialize_rq() for filesystem requests") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r--drivers/scsi/scsi_lib.c8
1 files changed, 1 insertions, 7 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9cf6a80fe297..ad3ea24f0885 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1379,8 +1379,6 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
ret = scsi_setup_cmnd(sdev, req);
out:
- if (ret != BLKPREP_OK)
- cmd->flags &= ~SCMD_INITIALIZED;
return scsi_prep_return(q, req, ret);
}
@@ -1900,7 +1898,6 @@ static int scsi_mq_prep_fn(struct request *req)
struct scsi_device *sdev = req->q->queuedata;
struct Scsi_Host *shost = sdev->host;
struct scatterlist *sg;
- int ret;
scsi_init_command(sdev, cmd);
@@ -1934,10 +1931,7 @@ static int scsi_mq_prep_fn(struct request *req)
blk_mq_start_request(req);
- ret = scsi_setup_cmnd(sdev, req);
- if (ret != BLK_STS_OK)
- cmd->flags &= ~SCMD_INITIALIZED;
- return ret;
+ return scsi_setup_cmnd(sdev, req);
}
static void scsi_mq_done(struct scsi_cmnd *cmd)

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