From ac514ffc968bf14649dd0e048447dc966ee49555 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Fri, 12 Jan 2018 19:53:40 -0500 Subject: dm mpath: delay the retry of a request if the target responded as busy Add DM_ENDIO_DELAY_REQUEUE to allow request-based multipath's multipath_end_io() to instruct dm-rq.c:dm_done() to delay a requeue. This is beneficial to do if BLK_STS_RESOURCE is returned from the target (because target is busy). Relative to blk-mq: kick the hw queues via blk_mq_requeue_work(), indirectly from dm-rq.c:__dm_mq_kick_requeue_list(), after a delay. For old .request_fn: use blk_delay_queue(). bio-based multipath doesn't have feature parity with request-based for retryable error requeues; that is something that'll need fixing in the future. Suggested-by: Bart Van Assche Signed-off-by: Mike Snitzer Acked-by: Bart Van Assche [as interpreted from Bart's "... patch looks fine to me."] --- include/linux/device-mapper.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/device-mapper.h') diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 9ba84532947d..da83f64952e7 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -550,6 +550,7 @@ do { \ #define DM_ENDIO_DONE 0 #define DM_ENDIO_INCOMPLETE 1 #define DM_ENDIO_REQUEUE 2 +#define DM_ENDIO_DELAY_REQUEUE 3 /* * Definitions of return values from target map function. @@ -557,7 +558,7 @@ do { \ #define DM_MAPIO_SUBMITTED 0 #define DM_MAPIO_REMAPPED 1 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE -#define DM_MAPIO_DELAY_REQUEUE 3 +#define DM_MAPIO_DELAY_REQUEUE DM_ENDIO_DELAY_REQUEUE #define DM_MAPIO_KILL 4 #define dm_sector_div64(x, y)( \ -- cgit v1.2.3-55-g7522