On Thu, 2017-04-27 at 07:46 +0200, Hannes Reinecke wrote:
> On 04/26/2017 08:37 PM, Bart Van Assche wrote:
> > + clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE, GFP_ATOMIC);
> > if (IS_ERR(clone)) {
> > /* EBUSY, ENODEV or EWOULDBLOCK: requeue */
> > - return r;
> > + pr_debug("blk_get_request() returned %ld%s - requeuing\n",
> > + PTR_ERR(clone), blk_queue_dying(q) ?
> > + " (path offline)" : "");
> > + if (blk_queue_dying(q)) {
> > + atomic_inc(&m->pg_init_in_progress);
> > + activate_path(pgpath);
> > + return DM_MAPIO_REQUEUE;
> > + }
> > + return DM_MAPIO_DELAY_REQUEUE;
> > }
> > clone->bio = clone->biotail = NULL;
> > clone->rq_disk = bdev->bd_disk;
>
> At the very least this does warrant some inline comments.
> Why do we call activate_path() here, seeing that the queue is dying?
Hello Hannes,
activate_path() is not only able to activate a path but can also change
the state of a path to offline. The body of the activate_path() function
makes that clear and that is why I had not added a comment above the
activate_path() call:
static void activate_path(struct pgpath *pgpath)
{
struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
if (pgpath->is_active && !blk_queue_dying(q))
scsi_dh_activate(q, pg_init_done, pgpath);
else
pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED);
}
Bart.