On Tue, 2017-02-14 at 16:25 -0800, Bart Van Assche wrote:
> If an initiator submits a LUN reset while a previous LUN reset is
> still being processed, both LUN resets will be added to dev_tmr_list.
> Avoid that this results in a circular wait between the two LUN resets
> by removing a LUN reset from dev_tmr_list before scanning that list
> for TMFs to wait for.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Fixes: c66ac9db8d4a ("target: Add LIO target core to kernel v2.6.38")
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: David Disseldorp <ddiss@xxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> ---
> drivers/target/target_core_tmr.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
> index 5eb164dac5cc..5c671fa67339 100644
> --- a/drivers/target/target_core_tmr.c
> +++ b/drivers/target/target_core_tmr.c
> @@ -230,13 +230,8 @@ static void core_tmr_drain_tmr_list(
> * LUN_RESET tmr..
> */
> spin_lock_irqsave(&dev->se_tmr_lock, flags);
> + list_del_init(&tmr->tmr_list);
> list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
> - /*
> - * Allow the received TMR to return with FUNCTION_COMPLETE.
> - */
> - if (tmr_p == tmr)
> - continue;
> -
> cmd = tmr_p->task_cmd;
> if (!cmd) {
> pr_err("Unable to locate struct se_cmd for TMR\n");
As-is I don't think this is a stand-alone upstream bug-fix without patch
#7, that allows multiple target_tmr_work() execute concurrently.
That is because target_tmr_work() only executes one context at a time
since se_device->tmr_wq is using WQ_UNBOUND w/ max_active = 1, so this
is not an issue.
However, I think it's a reasonable improvement on it's own, so I'll
apply it to target-pending/for-next with a slightly different
description and without the stable CC.