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 <snitzer@redhat.com>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index cfe5591..0c32b2b 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -83,7 +83,6 @@
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 @@
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 @@
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 3941fae..51d8229 100644
--- a/drivers/md/dm-queue-length.c
+++ b/drivers/md/dm-queue-length.c
@@ -23,8 +23,8 @@
#include <linux/atomic.h>
#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 @@
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 6ab1192..65ffdc3 100644
--- a/drivers/md/dm-round-robin.c
+++ b/drivers/md/dm-round-robin.c
@@ -17,6 +17,8 @@
#include <linux/module.h>
#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 @@
* Round-robin selector
*---------------------------------------------------------------*/
-#define RR_MIN_IO 1000
-
struct selector {
struct list_head valid_paths;
struct list_head invalid_paths;
@@ -127,6 +127,11 @@
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 @@
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 9df8f6b..0370eaf 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 @@
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)) {