On 01/08/2018 07:50 PM, Bart Van Assche wrote: > Several SCSI transport and LLD drivers surround code that does not > tolerate concurrent calls of .queuecommand() with scsi_target_block() / > scsi_target_unblock(). These last two functions use > blk_mq_quiesce_queue() / blk_mq_unquiesce_queue() for scsi-mq request > queues to prevent concurrent .queuecommand() calls. However, that is > not sufficient to prevent .queuecommand() calls from scsi_send_eh_cmnd(). > Hence surround the .queuecommand() call from the SCSI error handler with > blk_wait_if_quiesced() / blk_finish_wait_if_quiesced(). > > Note: converting the .queuecommand() call in scsi_send_eh_cmnd() into > code that calls blk_get_request(), e.g. scsi_execute_req(), is not an > option since scsi_send_eh_cmnd() can be called if all requests are > allocated and if no requests will make progress without aborting any > of these requests. > > Signed-off-by: Bart Van Assche <[email protected]> > Cc: Martin K. Petersen <[email protected]> > Cc: Christoph Hellwig <[email protected]> > Cc: Hannes Reinecke <[email protected]> > Cc: Johannes Thumshirn <[email protected]> > Cc: Ming Lei <[email protected]> > --- > drivers/scsi/scsi_error.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c > index 62b56de38ae8..5af3de1731a5 100644 > --- a/drivers/scsi/scsi_error.c > +++ b/drivers/scsi/scsi_error.c > @@ -1016,6 +1016,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, > unsigned char *cmnd, > { > struct scsi_device *sdev = scmd->device; > struct Scsi_Host *shost = sdev->host; > + struct request_queue *q = sdev->request_queue; > DECLARE_COMPLETION_ONSTACK(done); > unsigned long timeleft = timeout; > struct scsi_eh_save ses; > @@ -1028,7 +1029,9 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, > unsigned char *cmnd, > > scsi_log_send(scmd); > scmd->scsi_done = scsi_eh_done; > + blk_wait_if_quiesced(q); > rtn = shost->hostt->queuecommand(shost, scmd); > + blk_finish_wait_if_quiesced(q); > if (rtn) { > if (timeleft > stall_for) { > scsi_eh_restore_cmnd(scmd, &ses); > Reviewed-by: Hannes Reinecke <[email protected]>
Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
