BugLink: https://bugs.launchpad.net/bugs/1744300
Since we introduced blk-mq-sched, the tags->rqs[] array has been
dynamically assigned. So we need to check for NULL when iterating,
since there's a window of time where the bit is set, but we haven't
dynamically assigned the tags->rqs[] array position yet.
This is perfectly safe, since the memory backing of the request is
never going away while the device is alive.
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry-pick from commit
7f5562d5ecc44c757599b201df928ba52fa05047)
Signed-off-by: Guilherme G. Piccoli <gpiccoli@canonical.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
bitnr += tags->nr_reserved_tags;
rq = tags->rqs[bitnr];
bitnr += tags->nr_reserved_tags;
rq = tags->rqs[bitnr];
- if (rq->q == hctx->queue)
+ /*
+ * We can hit rq == NULL here, because the tagging functions
+ * test and set the bit before assining ->rqs[].
+ */
+ if (rq && rq->q == hctx->queue)
iter_data->fn(hctx, rq, iter_data->data, reserved);
return true;
}
iter_data->fn(hctx, rq, iter_data->data, reserved);
return true;
}
if (!reserved)
bitnr += tags->nr_reserved_tags;
if (!reserved)
bitnr += tags->nr_reserved_tags;
+
+ /*
+ * We can hit rq == NULL here, because the tagging functions
+ * test and set the bit before assining ->rqs[].
+ */
+ if (rq)
+ iter_data->fn(rq, iter_data->data, reserved);
- iter_data->fn(rq, iter_data->data, reserved);