On Mon, Jun 25, 2012 at 06:17:18PM +0000, Bart Van Assche wrote: > Avoid that the code for requeueing SCSI requests triggers a > crash by making sure that that code isn't scheduled anymore > after a device has been removed. > > Also, source code inspection of __scsi_remove_device() revealed > a race condition in this function: no new SCSI requests must be > accepted for a SCSI device after device removal started. > > Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> > Reviewed-by: Mike Christie <michaelc@xxxxxxxxxxx> > Cc: James Bottomley <JBottomley@xxxxxxxxxxxxx> > Cc: Jens Axboe <axboe@xxxxxxxxx> > Cc: Joe Lawrence <jdl1291@xxxxxxxxx> > Cc: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> > Cc: <stable@xxxxxxxxxx> > --- > drivers/scsi/scsi_lib.c | 7 ++++--- > drivers/scsi/scsi_sysfs.c | 11 +++++++++-- > 2 files changed, 13 insertions(+), 5 deletions(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 082c1e5..fc2b9f4 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -155,13 +155,14 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) > > /* > * Requeue this command. It will go before all other commands > - * that are already in the queue. > + * that are already in the queue. Schedule requeue work under > + * lock such that the kblockd_schedule_work() call happens > + * before blk_cleanup_queue() finishes. > */ > spin_lock_irqsave(q->queue_lock, flags); > blk_requeue_request(q, cmd->request); > - spin_unlock_irqrestore(q->queue_lock, flags); > - > kblockd_schedule_work(q, &device->requeue_work); > + spin_unlock_irqrestore(q->queue_lock, flags); This is rather subtle but yeah it would achieve proper synchronization. Can't think of a better way ATM. Aside from the nits, for all patches in this series Acked-by: Tejun Heo <tj@xxxxxxxxxx> Thanks! -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
