On 04/27/2017 05:11 PM, Bart Van Assche wrote: > 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); > } > So why not call 'pg_init_done()' directly and avoid the confusion? Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)