From: Bart Van Assche Date: Wed, 4 Mar 2015 09:31:47 +0000 (+0100) Subject: Defer processing of REQ_PREEMPT requests for blocked devices X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=bba0bdd7ad4713d82338bcd9b72d57e9335a664b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git Defer processing of REQ_PREEMPT requests for blocked devices 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: [] mlx4_ib_post_send+0xd2/0xb30 [mlx4_ib] Process rescan-scsi-bus (pid: 9241, threadinfo ffff88053484a000, task ffff880534aae100) Call Trace: [] srp_post_send+0x65/0x70 [ib_srp] [] srp_queuecommand+0x1cf/0x3e0 [ib_srp] [] scsi_dispatch_cmd+0x101/0x280 [scsi_mod] [] scsi_request_fn+0x411/0x4d0 [scsi_mod] [] __blk_run_queue+0x27/0x30 [] blk_execute_rq_nowait+0x82/0x110 [] blk_execute_rq+0x62/0xf0 [] scsi_execute+0xe8/0x190 [scsi_mod] [] scsi_execute_req+0xa3/0x130 [scsi_mod] [] scsi_probe_lun+0x17a/0x450 [scsi_mod] [] scsi_probe_and_add_lun+0x156/0x480 [scsi_mod] [] __scsi_scan_target+0xdf/0x1f0 [scsi_mod] [] scsi_scan_host_selected+0x183/0x1c0 [scsi_mod] [] scsi_scan+0xdb/0xe0 [scsi_mod] [] store_scan+0x13/0x20 [scsi_mod] [] sysfs_write_file+0xcb/0x160 [] vfs_write+0xce/0x140 [] sys_write+0x53/0xa0 [] system_call_fastpath+0x16/0x1b [<00007f611c9d9300>] 0x7f611c9d92ff Reported-by: Max Gurtuvoy Signed-off-by: Bart Van Assche Reviewed-by: Mike Christie Cc: Signed-off-by: James Bottomley --- diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 54d7a6cbb98a..b1a263137a23 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1311,9 +1311,11 @@ scsi_prep_state_check(struct scsi_device *sdev, struct request *req) "rejecting I/O to dead device\n"); ret = BLKPREP_KILL; break; - case SDEV_QUIESCE: case SDEV_BLOCK: case SDEV_CREATED_BLOCK: + ret = BLKPREP_DEFER; + break; + case SDEV_QUIESCE: /* * If the devices is blocked we defer normal commands. */ diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index c294e3e25e37..a1b25e35ea5f 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -181,7 +181,9 @@ enum rq_flag_bits { __REQ_ELVPRIV, /* elevator private data attached */ __REQ_FAILED, /* set if the request failed */ __REQ_QUIET, /* don't worry about errors */ - __REQ_PREEMPT, /* set for "ide_preempt" requests */ + __REQ_PREEMPT, /* set for "ide_preempt" requests and also + for requests for which the SCSI "quiesce" + state must be ignored. */ __REQ_ALLOCED, /* request came from our alloc pool */ __REQ_COPY_USER, /* contains copies of user pages */ __REQ_FLUSH_SEQ, /* request for flush sequence */