On Wed, 10 Jun 2009 00:56:05 -0700
Giridhar Malavali <giridhar.malavali@xxxxxxxxxx> wrote:
>
> After applying the changes from Fujita, I see that application never
> completes when BSG time out happens. Once the BSG request times out,
> I see fc_bsg_softirq_done routine destroying the bsg_job but does not
> send any response back to the application. The application infinitely
> waits for the response with following warning message
>
> Jun 9 17:22:09 elab60 kernel: [ 480.666830]INFO: task sgv4_els:6058
> blocked for more than 120 seconds.
> Jun 9 17:22:09 elab60 kernel: [ 480.666833] "echo 0 > /proc/sys/
> kernel/hung_task_timeout_secs" disables this message.
> Jun 9 17:22:09 elab60 kernel: [ 480.666835] sgv4_els D
> 0000000000000000 0 6058 5993
> Jun 9 17:22:09 elab60 kernel: [ 480.666838] ffff88007f173b78
> 0000000000000082 0000000000000000 ffffffffa003f880
> Jun 9 17:22:09 elab60 kernel: [ 480.666842] ffff880001030000
> 000000000000ff00 000000000000c8b8 ffff88007fbf6990
> Jun 9 17:22:09 elab60 kernel: [ 480.666845] ffff88007fbf6c18
> 00000001a00382cf 00000000ffff3524 ffff88007f93c990
> Jun 9 17:22:09 elab60 kernel: [ 480.666848] Call Trace:
> Jun 9 17:22:09 elab60 kernel: [ 480.666858] [<ffffffffa00015d2>] ?
> fc_bsg_map_buffer+0x2a/0x72 [scsi_transport_fc]
> Jun 9 17:22:09 elab60 kernel: [ 480.666864] [<ffffffff8029a2ba>] ?
> cache_alloc_debugcheck_after+0x73/0x243
> Jun 9 17:22:09 elab60 kernel: [ 480.666868] [<ffffffff80511ebe>]
> schedule+0x9/0x1d
> Jun 9 17:22:09 elab60 kernel: [ 480.666871] [<ffffffff8051210f>]
> schedule_timeout+0x12f/0x164
> Jun 9 17:22:09 elab60 kernel: [ 480.666873] [<ffffffff805113f7>]
> wait_for_common+0xb8/0x15e
> Jun 9 17:22:09 elab60 kernel: [ 480.666878] [<ffffffff80230feb>] ?
> default_wake_function+0x0/0xf
> Jun 9 17:22:09 elab60 kernel: [ 480.666880] [<ffffffff80511527>]
> wait_for_completion+0x18/0x1a
> Jun 9 17:22:09 elab60 kernel: [ 480.666884] [<ffffffff80360da6>]
> blk_execute_rq+0x7f/0xc9
> Jun 9 17:22:09 elab60 kernel: [ 480.666887] [<ffffffff80365c28>]
> bsg_ioctl+0x1c0/0x227
> Jun 9 17:22:09 elab60 kernel: [ 480.666890] [<ffffffff80514362>] ?
> _spin_unlock_irqrestore+0x2b/0x32
> Jun 9 17:22:09 elab60 kernel: [ 480.666894] [<ffffffff802adb36>]
> vfs_ioctl+0x2a/0x95
> Jun 9 17:22:09 elab60 kernel: [ 480.666896] [<ffffffff802adc22>]
> do_vfs_ioctl+0x81/0x583
> Jun 9 17:22:09 elab60 kernel: [ 480.666898] [<ffffffff80514372>] ?
> _spin_unlock+0x9/0xb
> Jun 9 17:22:09 elab60 kernel: [ 480.666901] [<ffffffff802ae165>]
> sys_ioctl+0x41/0x65
> Jun 9 17:22:09 elab60 kernel: [ 480.666904] [<ffffffff8020b26b>]
> system_call_fastpath+0x16/0x1b
Oops, sorry about that.
> I see that function blk_end_request_all calls blk_finish_request
> routine to complete the response to application. After adding this
> call in fc_bsg_softirq_done function, the application gets the
> response and completes.
>
> Is this a proper fix? How does block layer request completes when
> timeout happens?
Looks ok to me. You need to complete such requests (as your fix does
in fc_bsg_softirq_done), if I understand correctly.
> /**
> * fc_bsg_softirq_done - softirq done routine for destroying the bsg
> requests
> * @req: BSG request that holds the job to be destroyed
> */
> static void fc_bsg_softirq_done(struct request *rq)
> {
> struct fc_bsg_job *job = rq->special;
> unsigned long flags;
>
> spin_lock_irqsave(&job->job_lock, flags);
> + job->state_flags |= FC_RQST_STATE_DONE;
> job->ref_cnt--;
> spin_unlock_irqrestore(&job->job_lock, flags);
> + blk_end_request_all(rq, rq->errors);
> fc_destroy_bsgjob(job);
>
My previous patch with this fix is fine by me for now.
However, as I proposed in the previous mail, I think that it would be
clean if we use q->softirq_done_fn for all the requests not only for
expired requests because fc_bsg_jobdone() does the part of what
fc_bsg_softirq_done() does.
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