Can I get another review for this one?
On Sun, Aug 31, 2014 at 07:09:59PM -0400, Douglas Gilbert wrote:
> A deadlock has been reported when the completion
> of SCSI commands (simulated by a timer) was surprised
> by a module removal. This patch removes one half of
> the offending locks around timer deletions. This fix
> is applied both to stop_all_queued() which is were
> the deadlock was discovered and stop_queued_cmnd()
> which has very similar logic.
>
> This patch should be applied both to the lk 3.17 tree
> and Christoph's drivers-for-3.18 tree.
>
> Tested-and-reported-by: Milan Broz <gmazyland@xxxxxxxxx>
> Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
> --- a/drivers/scsi/scsi_debug.c 2014-08-26 13:24:51.646948507 -0400
> +++ b/drivers/scsi/scsi_debug.c 2014-08-30 18:04:54.589226679 -0400
> @@ -2743,6 +2743,13 @@ static int stop_queued_cmnd(struct scsi_
> if (test_bit(k, queued_in_use_bm)) {
> sqcp = &queued_arr[k];
> if (cmnd == sqcp->a_cmnd) {
> + devip = (struct sdebug_dev_info *)
> + cmnd->device->hostdata;
> + if (devip)
> + atomic_dec(&devip->num_in_q);
> + sqcp->a_cmnd = NULL;
> + spin_unlock_irqrestore(&queued_arr_lock,
> + iflags);
> if (scsi_debug_ndelay > 0) {
> if (sqcp->sd_hrtp)
> hrtimer_cancel(
> @@ -2755,18 +2762,13 @@ static int stop_queued_cmnd(struct scsi_
> if (sqcp->tletp)
> tasklet_kill(sqcp->tletp);
> }
> - __clear_bit(k, queued_in_use_bm);
> - devip = (struct sdebug_dev_info *)
> - cmnd->device->hostdata;
> - if (devip)
> - atomic_dec(&devip->num_in_q);
> - sqcp->a_cmnd = NULL;
> - break;
> + clear_bit(k, queued_in_use_bm);
> + return 1;
> }
> }
> }
> spin_unlock_irqrestore(&queued_arr_lock, iflags);
> - return (k < qmax) ? 1 : 0;
> + return 0;
> }
>
> /* Deletes (stops) timers or tasklets of all queued commands */
> @@ -2782,6 +2784,13 @@ static void stop_all_queued(void)
> if (test_bit(k, queued_in_use_bm)) {
> sqcp = &queued_arr[k];
> if (sqcp->a_cmnd) {
> + devip = (struct sdebug_dev_info *)
> + sqcp->a_cmnd->device->hostdata;
> + if (devip)
> + atomic_dec(&devip->num_in_q);
> + sqcp->a_cmnd = NULL;
> + spin_unlock_irqrestore(&queued_arr_lock,
> + iflags);
> if (scsi_debug_ndelay > 0) {
> if (sqcp->sd_hrtp)
> hrtimer_cancel(
> @@ -2794,12 +2803,8 @@ static void stop_all_queued(void)
> if (sqcp->tletp)
> tasklet_kill(sqcp->tletp);
> }
> - __clear_bit(k, queued_in_use_bm);
> - devip = (struct sdebug_dev_info *)
> - sqcp->a_cmnd->device->hostdata;
> - if (devip)
> - atomic_dec(&devip->num_in_q);
> - sqcp->a_cmnd = NULL;
> + clear_bit(k, queued_in_use_bm);
> + spin_lock_irqsave(&queued_arr_lock, iflags);
> }
> }
> }
---end quoted text---
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