From 21136f89d76dc10d31d294f2bb79c585a039bad6 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Wed, 10 Feb 2016 11:58:45 -0500 Subject: [PATCH] dm mpath: remove repeat_count support from multipath core Preparation for making __multipath_map() avoid taking the m->lock spinlock -- in favor of using RCU locking. repeat_count was primarily for bio-based DM multipath's benefit. There is really no need for it anymore now that DM multipath is request-based. As such, repeat_count > 1 is no longer honored and a warning is displayed if the user attempts to use a value > 1. This is a temporary change for the round-robin path-selector (as a later commit will restore its support for repeat_count > 1). Signed-off-by: Mike Snitzer --- drivers/md/dm-mpath.c | 7 +++---- drivers/md/dm-queue-length.c | 9 +++++++-- drivers/md/dm-round-robin.c | 11 ++++++++--- drivers/md/dm-service-time.c | 7 ++++++- 4 files changed, 24 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index cfe55910699d..0c32b2b7856c 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -83,7 +83,6 @@ struct multipath { struct pgpath *current_pgpath; struct priority_group *current_pg; struct priority_group *next_pg; /* Switch to this PG if set */ - unsigned repeat_count; /* I/Os left before calling PS again */ unsigned queue_io:1; /* Must we queue all I/O? */ unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */ @@ -319,8 +318,9 @@ static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, size_t nr_bytes) { struct dm_path *path; + unsigned repeat_count; - path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); + path = pg->ps.type->select_path(&pg->ps, &repeat_count, nr_bytes); if (!path) return -ENXIO; @@ -412,8 +412,7 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, spin_lock_irq(&m->lock); /* Do we need to select a new pgpath? */ - if (!m->current_pgpath || - (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) + if (!m->current_pgpath || !m->queue_io) __choose_pgpath(m, nr_bytes); pgpath = m->current_pgpath; diff --git a/drivers/md/dm-queue-length.c b/drivers/md/dm-queue-length.c index 3941fae0de9f..51d82290ad4c 100644 --- a/drivers/md/dm-queue-length.c +++ b/drivers/md/dm-queue-length.c @@ -23,8 +23,8 @@ #include #define DM_MSG_PREFIX "multipath queue-length" -#define QL_MIN_IO 128 -#define QL_VERSION "0.1.0" +#define QL_MIN_IO 1 +#define QL_VERSION "0.2.0" struct selector { struct list_head valid_paths; @@ -129,6 +129,11 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path, return -EINVAL; } + if (repeat_count > 1) { + DMWARN_LIMIT("repeat_count > 1 is deprecated, using 1 instead"); + repeat_count = 1; + } + /* Allocate the path information structure */ pi = kmalloc(sizeof(*pi), GFP_KERNEL); if (!pi) { diff --git a/drivers/md/dm-round-robin.c b/drivers/md/dm-round-robin.c index 6ab1192cdd5f..65ffdc3403b6 100644 --- a/drivers/md/dm-round-robin.c +++ b/drivers/md/dm-round-robin.c @@ -17,6 +17,8 @@ #include #define DM_MSG_PREFIX "multipath round-robin" +#define RR_MIN_IO 1 +#define RR_VERSION "1.1.0" /*----------------------------------------------------------------- * Path-handling code, paths are held in lists @@ -41,8 +43,6 @@ static void free_paths(struct list_head *paths) * Round-robin selector *---------------------------------------------------------------*/ -#define RR_MIN_IO 1000 - struct selector { struct list_head valid_paths; struct list_head invalid_paths; @@ -127,6 +127,11 @@ static int rr_add_path(struct path_selector *ps, struct dm_path *path, return -EINVAL; } + if (repeat_count > 1) { + DMWARN_LIMIT("repeat_count > 1 is deprecated, using 1 instead"); + repeat_count = 1; + } + /* allocate the path */ pi = kmalloc(sizeof(*pi), GFP_KERNEL); if (!pi) { @@ -198,7 +203,7 @@ static int __init dm_rr_init(void) if (r < 0) DMERR("register failed %d", r); - DMINFO("version 1.0.0 loaded"); + DMINFO("version " RR_VERSION " loaded"); return r; } diff --git a/drivers/md/dm-service-time.c b/drivers/md/dm-service-time.c index 9df8f6bd6418..0370eaf3d949 100644 --- a/drivers/md/dm-service-time.c +++ b/drivers/md/dm-service-time.c @@ -19,7 +19,7 @@ #define ST_MAX_RELATIVE_THROUGHPUT 100 #define ST_MAX_RELATIVE_THROUGHPUT_SHIFT 7 #define ST_MAX_INFLIGHT_SIZE ((size_t)-1 >> ST_MAX_RELATIVE_THROUGHPUT_SHIFT) -#define ST_VERSION "0.2.0" +#define ST_VERSION "0.3.0" struct selector { struct list_head valid_paths; @@ -134,6 +134,11 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path, return -EINVAL; } + if (repeat_count > 1) { + DMWARN_LIMIT("repeat_count > 1 is deprecated, using 1 instead"); + repeat_count = 1; + } + if ((argc == 2) && (sscanf(argv[1], "%u%c", &relative_throughput, &dummy) != 1 || relative_throughput > ST_MAX_RELATIVE_THROUGHPUT)) { -- 2.20.1