On 9/7/21 9:07 AM, Niklas Cassel wrote:
On Tue, Sep 07, 2021 at 07:54:09AM -0700, Bart Van Assche wrote:
Please take a look at
https://lore.kernel.org/linux-block/18594aff-4a94-8a48-334c-f21ae32120c6@xxxxxxx/
If dd_prepare_request() is removed I will have to reintroduce it.
dd_prepare_request() itself is not removed, just the
rq->elv.priv[0] = NULL; inside dd_prepare_request().
If you need to modify dd_prepare_request() in a future
commit, that should be fine, no?
Without patch 1/2, e->type->ops.requeue_request() can get called
both for requests that bypassed the I/O scheduler, and for requests
that were inserted in the I/O scheduler.
See:
block/blk-mq-sched.h:blk_mq_sched_requeue_request()
If the RQF_ELVPRIV flag is not set, e->type->ops.requeue_request()
will not be called.
Perhaps you are having issues with requests that were inserted
in the scheduler, but later requeued?
If so, shouldn't these fixes help you, since you do not need to
worry about passthrough requests resulting in spurious calls to
the I/O scheduler callbacks?
In my comment I was indeed referring to requeued requests. If a request
is requeued the scheduler insert callback function is called multiple
times. From my point of view this patch series doesn't help much since
requeued requests are not addressed.
Thanks,
Bart.
