Commit 21136f89 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

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: default avatarMike Snitzer <snitzer@redhat.com>
parent 7943bd6d

drivers/md/dm-mpath.c

+3 −4
Original line number Diff line number Diff line
@@ -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;

drivers/md/dm-queue-length.c

+7 −2
Original line number Diff line number Diff line
@@ -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 @@ 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) {

drivers/md/dm-round-robin.c

+8 −3
Original line number Diff line number Diff line
@@ -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 @@ 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;

}

drivers/md/dm-service-time.c

+6 −1
Original line number Diff line number Diff line
@@ -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)) {

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