dm: rename multipath path selector source files to have "dm-ps" prefix

Additional prefix helps clarify that these source files implement path
selectors.

Required updating Makefile to still build modules _without_ the
"dm-ps" prefix to preserve dm-multipath's ability to autoload path
selector modules. While at it, cleaned up some DM whitespace in
Makefile.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 0 insertions, 362 deletions

diff --git a/drivers/md/dm-service-time.c b/drivers/md/dm-service-time.c
deleted file mode 100644
index 9cfda665e9eb..000000000000
--- a/drivers/md/dm-service-time.c
+++ /dev/null
@@ -1,362 +0,0 @@
-/*
- * Copyright (C) 2007-2009 NEC Corporation.  All Rights Reserved.
- *
- * Module Author: Kiyoshi Ueda
- *
- * This file is released under the GPL.
- *
- * Throughput oriented path selector.
- */
-
-#include "dm.h"
-#include "dm-path-selector.h"
-
-#include <linux/slab.h>
-#include <linux/module.h>
-
-#define DM_MSG_PREFIX	"multipath service-time"
-#define ST_MIN_IO	1
-#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	"0.3.0"
-
-struct selector {
-	struct list_head valid_paths;
-	struct list_head failed_paths;
-	spinlock_t lock;
-};
-
-struct path_info {
-	struct list_head list;
-	struct dm_path *path;
-	unsigned repeat_count;
-	unsigned relative_throughput;
-	atomic_t in_flight_size;	/* Total size of in-flight I/Os */
-};
-
-static struct selector *alloc_selector(void)
-{
-	struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL);
-
-	if (s) {
-		INIT_LIST_HEAD(&s->valid_paths);
-		INIT_LIST_HEAD(&s->failed_paths);
-		spin_lock_init(&s->lock);
-	}
-
-	return s;
-}
-
-static int st_create(struct path_selector *ps, unsigned argc, char **argv)
-{
-	struct selector *s = alloc_selector();
-
-	if (!s)
-		return -ENOMEM;
-
-	ps->context = s;
-	return 0;
-}
-
-static void free_paths(struct list_head *paths)
-{
-	struct path_info *pi, *next;
-
-	list_for_each_entry_safe(pi, next, paths, list) {
-		list_del(&pi->list);
-		kfree(pi);
-	}
-}
-
-static void st_destroy(struct path_selector *ps)
-{
-	struct selector *s = ps->context;
-
-	free_paths(&s->valid_paths);
-	free_paths(&s->failed_paths);
-	kfree(s);
-	ps->context = NULL;
-}
-
-static int st_status(struct path_selector *ps, struct dm_path *path,
-		     status_type_t type, char *result, unsigned maxlen)
-{
-	unsigned sz = 0;
-	struct path_info *pi;
-
-	if (!path)
-		DMEMIT("0 ");
-	else {
-		pi = path->pscontext;
-
-		switch (type) {
-		case STATUSTYPE_INFO:
-			DMEMIT("%d %u ", atomic_read(&pi->in_flight_size),
-			       pi->relative_throughput);
-			break;
-		case STATUSTYPE_TABLE:
-			DMEMIT("%u %u ", pi->repeat_count,
-			       pi->relative_throughput);
-			break;
-		}
-	}
-
-	return sz;
-}
-
-static int st_add_path(struct path_selector *ps, struct dm_path *path,
-		       int argc, char **argv, char **error)
-{
-	struct selector *s = ps->context;
-	struct path_info *pi;
-	unsigned repeat_count = ST_MIN_IO;
-	unsigned relative_throughput = 1;
-	char dummy;
-	unsigned long flags;
-
-	/*
-	 * Arguments: [<repeat_count> [<relative_throughput>]]
-	 * 	<repeat_count>: The number of I/Os before switching path.
-	 * 			If not given, default (ST_MIN_IO) is used.
-	 * 	<relative_throughput>: The relative throughput value of
-	 *			the path among all paths in the path-group.
-	 * 			The valid range: 0-<ST_MAX_RELATIVE_THROUGHPUT>
-	 *			If not given, minimum value '1' is used.
-	 *			If '0' is given, the path isn't selected while
-	 * 			other paths having a positive value are
-	 * 			available.
-	 */
-	if (argc > 2) {
-		*error = "service-time ps: incorrect number of arguments";
-		return -EINVAL;
-	}
-
-	if (argc && (sscanf(argv[0], "%u%c", &repeat_count, &dummy) != 1)) {
-		*error = "service-time ps: invalid repeat count";
-		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)) {
-		*error = "service-time ps: invalid relative_throughput value";
-		return -EINVAL;
-	}
-
-	/* allocate the path */
-	pi = kmalloc(sizeof(*pi), GFP_KERNEL);
-	if (!pi) {
-		*error = "service-time ps: Error allocating path context";
-		return -ENOMEM;
-	}
-
-	pi->path = path;
-	pi->repeat_count = repeat_count;
-	pi->relative_throughput = relative_throughput;
-	atomic_set(&pi->in_flight_size, 0);
-
-	path->pscontext = pi;
-
-	spin_lock_irqsave(&s->lock, flags);
-	list_add_tail(&pi->list, &s->valid_paths);
-	spin_unlock_irqrestore(&s->lock, flags);
-
-	return 0;
-}
-
-static void st_fail_path(struct path_selector *ps, struct dm_path *path)
-{
-	struct selector *s = ps->context;
-	struct path_info *pi = path->pscontext;
-	unsigned long flags;
-
-	spin_lock_irqsave(&s->lock, flags);
-	list_move(&pi->list, &s->failed_paths);
-	spin_unlock_irqrestore(&s->lock, flags);
-}
-
-static int st_reinstate_path(struct path_selector *ps, struct dm_path *path)
-{
-	struct selector *s = ps->context;
-	struct path_info *pi = path->pscontext;
-	unsigned long flags;
-
-	spin_lock_irqsave(&s->lock, flags);
-	list_move_tail(&pi->list, &s->valid_paths);
-	spin_unlock_irqrestore(&s->lock, flags);
-
-	return 0;
-}
-
-/*
- * Compare the estimated service time of 2 paths, pi1 and pi2,
- * for the incoming I/O.
- *
- * Returns:
- * < 0 : pi1 is better
- * 0   : no difference between pi1 and pi2
- * > 0 : pi2 is better
- *
- * Description:
- * Basically, the service time is estimated by:
- *     ('pi->in-flight-size' + 'incoming') / 'pi->relative_throughput'
- * To reduce the calculation, some optimizations are made.
- * (See comments inline)
- */
-static int st_compare_load(struct path_info *pi1, struct path_info *pi2,
-			   size_t incoming)
-{
-	size_t sz1, sz2, st1, st2;
-
-	sz1 = atomic_read(&pi1->in_flight_size);
-	sz2 = atomic_read(&pi2->in_flight_size);
-
-	/*
-	 * Case 1: Both have same throughput value. Choose less loaded path.
-	 */
-	if (pi1->relative_throughput == pi2->relative_throughput)
-		return sz1 - sz2;
-
-	/*
-	 * Case 2a: Both have same load. Choose higher throughput path.
-	 * Case 2b: One path has no throughput value. Choose the other one.
-	 */
-	if (sz1 == sz2 ||
-	    !pi1->relative_throughput || !pi2->relative_throughput)
-		return pi2->relative_throughput - pi1->relative_throughput;
-
-	/*
-	 * Case 3: Calculate service time. Choose faster path.
-	 *         Service time using pi1:
-	 *             st1 = (sz1 + incoming) / pi1->relative_throughput
-	 *         Service time using pi2:
-	 *             st2 = (sz2 + incoming) / pi2->relative_throughput
-	 *
-	 *         To avoid the division, transform the expression to use
-	 *         multiplication.
-	 *         Because ->relative_throughput > 0 here, if st1 < st2,
-	 *         the expressions below are the same meaning:
-	 *             (sz1 + incoming) / pi1->relative_throughput <
-	 *                 (sz2 + incoming) / pi2->relative_throughput
-	 *             (sz1 + incoming) * pi2->relative_throughput <
-	 *                 (sz2 + incoming) * pi1->relative_throughput
-	 *         So use the later one.
-	 */
-	sz1 += incoming;
-	sz2 += incoming;
-	if (unlikely(sz1 >= ST_MAX_INFLIGHT_SIZE ||
-		     sz2 >= ST_MAX_INFLIGHT_SIZE)) {
-		/*
-		 * Size may be too big for multiplying pi->relative_throughput
-		 * and overflow.
-		 * To avoid the overflow and mis-selection, shift down both.
-		 */
-		sz1 >>= ST_MAX_RELATIVE_THROUGHPUT_SHIFT;
-		sz2 >>= ST_MAX_RELATIVE_THROUGHPUT_SHIFT;
-	}
-	st1 = sz1 * pi2->relative_throughput;
-	st2 = sz2 * pi1->relative_throughput;
-	if (st1 != st2)
-		return st1 - st2;
-
-	/*
-	 * Case 4: Service time is equal. Choose higher throughput path.
-	 */
-	return pi2->relative_throughput - pi1->relative_throughput;
-}
-
-static struct dm_path *st_select_path(struct path_selector *ps, size_t nr_bytes)
-{
-	struct selector *s = ps->context;
-	struct path_info *pi = NULL, *best = NULL;
-	struct dm_path *ret = NULL;
-	unsigned long flags;
-
-	spin_lock_irqsave(&s->lock, flags);
-	if (list_empty(&s->valid_paths))
-		goto out;
-
-	list_for_each_entry(pi, &s->valid_paths, list)
-		if (!best || (st_compare_load(pi, best, nr_bytes) < 0))
-			best = pi;
-
-	if (!best)
-		goto out;
-
-	/* Move most recently used to least preferred to evenly balance. */
-	list_move_tail(&best->list, &s->valid_paths);
-
-	ret = best->path;
-out:
-	spin_unlock_irqrestore(&s->lock, flags);
-	return ret;
-}
-
-static int st_start_io(struct path_selector *ps, struct dm_path *path,
-		       size_t nr_bytes)
-{
-	struct path_info *pi = path->pscontext;
-
-	atomic_add(nr_bytes, &pi->in_flight_size);
-
-	return 0;
-}
-
-static int st_end_io(struct path_selector *ps, struct dm_path *path,
-		     size_t nr_bytes, u64 start_time)
-{
-	struct path_info *pi = path->pscontext;
-
-	atomic_sub(nr_bytes, &pi->in_flight_size);
-
-	return 0;
-}
-
-static struct path_selector_type st_ps = {
-	.name		= "service-time",
-	.module		= THIS_MODULE,
-	.table_args	= 2,
-	.info_args	= 2,
-	.create		= st_create,
-	.destroy	= st_destroy,
-	.status		= st_status,
-	.add_path	= st_add_path,
-	.fail_path	= st_fail_path,
-	.reinstate_path	= st_reinstate_path,
-	.select_path	= st_select_path,
-	.start_io	= st_start_io,
-	.end_io		= st_end_io,
-};
-
-static int __init dm_st_init(void)
-{
-	int r = dm_register_path_selector(&st_ps);
-
-	if (r < 0)
-		DMERR("register failed %d", r);
-
-	DMINFO("version " ST_VERSION " loaded");
-
-	return r;
-}
-
-static void __exit dm_st_exit(void)
-{
-	int r = dm_unregister_path_selector(&st_ps);
-
-	if (r < 0)
-		DMERR("unregister failed %d", r);
-}
-
-module_init(dm_st_init);
-module_exit(dm_st_exit);
-
-MODULE_DESCRIPTION(DM_NAME " throughput oriented path selector");
-MODULE_AUTHOR("Kiyoshi Ueda <k-ueda@ct.jp.nec.com>");
-MODULE_LICENSE("GPL");