* [PATCH, resend] Defer processing of REQ_PREEMPT requests for blocked devices
@ 2015-03-04 9:31 Bart Van Assche
2015-04-06 15:37 ` Mike Christie
0 siblings, 1 reply; 2+ messages in thread
From: Bart Van Assche @ 2015-03-04 9:31 UTC (permalink / raw)
To: James Bottomley
Cc: Max Gurtovoy, Mike Christie, Christoph Hellwig, Sagi Grimberg,
linux-scsi@vger.kernel.org
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: Max Gurtuvoy <maxg@mellanox.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org>
---
drivers/scsi/scsi_lib.c | 4 +++-
include/linux/blk_types.h | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 54d7a6c..b1a2631 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 c294e3e..a1b25e3 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 */
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH, resend] Defer processing of REQ_PREEMPT requests for blocked devices
2015-03-04 9:31 [PATCH, resend] Defer processing of REQ_PREEMPT requests for blocked devices Bart Van Assche
@ 2015-04-06 15:37 ` Mike Christie
0 siblings, 0 replies; 2+ messages in thread
From: Mike Christie @ 2015-04-06 15:37 UTC (permalink / raw)
To: Bart Van Assche, James Bottomley
Cc: Max Gurtovoy, Christoph Hellwig, Sagi Grimberg,
linux-scsi@vger.kernel.org
On 03/04/2015 03:31 AM, Bart Van Assche wrote:
> 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: Max Gurtuvoy <maxg@mellanox.com>
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: Mike Christie <michaelc@cs.wisc.edu>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Sagi Grimberg <sagig@mellanox.com>
> Cc: <stable@vger.kernel.org>
> ---
> drivers/scsi/scsi_lib.c | 4 +++-
> include/linux/blk_types.h | 4 +++-
> 2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 54d7a6c..b1a2631 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 c294e3e..a1b25e3 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 */
>
Look ok to me. Also tested here with iscsi and FC.
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-04-06 15:37 ` Mike Christie
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