--- linux-2.6.2/drivers/md/dm-mpath.c 2004-02-10 17:33:58.000000000 -0800
+++ linux-2.6.2-work/drivers/md/dm-mpath.c 2004-02-10 23:24:14.000000000 -0800
@@ -16,6 +16,8 @@
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/time.h>
+#include <linux/workqueue.h>
+#include <linux/timer.h>
#include <asm/atomic.h>
#define MPATH_FAIL_COUNT 1
@@ -62,17 +64,18 @@ struct multipath {
struct list_head priority_groups;
spinlock_t lock;
- unsigned nr_valid_paths;
- unsigned nr_tested_paths;
struct path *current_path;
unsigned current_count;
unsigned min_io;
+ struct work_struct dispatch_failed;
struct bio_list failed_ios;
- struct bio_list test_ios;
+ struct work_struct test_pgroup;
+ struct timer_list test_timer;
unsigned test_interval;
+
unsigned trigger_event;
};
@@ -159,6 +162,9 @@ static void free_priority_group(struct p
kfree(pg);
}
+static void dispatch_failed_ios(void *data);
+static void test_pgroup(void *data);
+
static struct multipath *alloc_multipath(void)
{
struct multipath *m;
@@ -169,6 +175,9 @@ static struct multipath *alloc_multipath
INIT_LIST_HEAD(&m->priority_groups);
m->lock = SPIN_LOCK_UNLOCKED;
m->min_io = MPATH_MIN_IO;
+ INIT_WORK(&m->dispatch_failed, dispatch_failed_ios, m);
+ INIT_WORK(&m->test_pgroup, test_pgroup, m);
+ init_timer(&m->test_timer);
}
return m;
@@ -187,7 +196,7 @@ static void free_multipath(struct multip
}
/*-----------------------------------------------------------------
- * All paths should be tested periodically.
+ * All valid paths should be tested periodically.
*---------------------------------------------------------------*/
static void iterate_paths(struct multipath *m, void (*fn)(struct path *p))
{
@@ -200,15 +209,9 @@ static void iterate_paths(struct multipa
}
}
-static void clear_tested(struct path *p)
-{
- p->tested = 0;
-}
-
static void fail_path(struct path *path)
{
unsigned long flags;
- struct multipath *m;
spin_lock_irqsave(&path->failed_lock, flags);
@@ -218,24 +221,6 @@ static void fail_path(struct path *path)
path->fail_total++;
path->pg->ps->type->set_path_state(path->pg->ps, path, 0);
path->pg->m->trigger_event = 1;
-
- m = path->pg->m;
- spin_lock(&m->lock);
- m->nr_valid_paths--;
- if (!m->nr_valid_paths) {
- iterate_paths(m, clear_tested);
- m->nr_tested_paths = 0;
- }
- spin_unlock(&m->lock);
- }
-
- if (!path->tested) {
- path->tested = 1;
-
- m = path->pg->m;
- spin_lock(&m->lock);
- m->nr_tested_paths++;
- spin_unlock(&m->lock);
}
spin_unlock_irqrestore(&path->failed_lock, flags);
@@ -253,10 +238,6 @@ static void recover_path(struct path *pa
path->fail_count = MPATH_FAIL_COUNT;
path->pg->ps->type->set_path_state(path->pg->ps, path, 1);
m->trigger_event = 1;
-
- spin_lock(&m->lock);
- m->nr_valid_paths++;
- spin_unlock(&m->lock);
}
spin_unlock_irqrestore(&path->failed_lock, flags);
@@ -278,40 +259,61 @@ static int test_endio(struct bio *bio, u
return 0;
}
-static void test_path(struct path *p)
+static void test_pgroup(void *data)
{
- /*
- * If we get this lock we're allowed to issue a test io
- * for this path.
- */
- if (down_trylock(&p->test_lock))
- return;
+ struct multipath *m = (struct multipath *)data;
+ struct priority_group *pg;
+ struct path *p;
+ unsigned long flags;
- p->test_bio->bi_sector = 0;
- p->test_bio->bi_bdev = p->dev->bdev;
- p->test_bio->bi_size = bdev_hardsect_size(p->dev->bdev);
- p->test_bio->bi_idx = 0;
+ spin_lock_irqsave(&m->lock, flags);
+ p = m->current_path;
+ spin_unlock_irqrestore(&m->lock, flags);
- bio_list_add(&p->pg->m->test_ios, p->test_bio);
+ if (!p)
+ return;
+
+ pg = p->pg;
+ list_for_each_entry (p, &pg->paths, list) {
+ /* TODO - add test for path idleness */
+
+ /*
+ * If we get this lock we're allowed to issue a test io
+ * for this path.
+ */
+ if (down_trylock(&p->test_lock))
+ continue;
+
+ p->test_bio->bi_sector = 0;
+ p->test_bio->bi_bdev = p->dev->bdev;
+ p->test_bio->bi_size = bdev_hardsect_size(p->dev->bdev);
+ p->test_bio->bi_idx = 0;
+
+ generic_make_request(p->test_bio);
+ }
}
/*-----------------------------------------------------------------
- * The multipath daemon is responsible for resubmitting failed ios.
+ * The multipath daemon is responsible for submitting failed and
+ * path test ios.
*---------------------------------------------------------------*/
-static struct dm_daemon _kmpathd;
+static struct workqueue_struct *_kmpathd_wq;
-static LIST_HEAD(_mpaths);
-static spinlock_t _mpath_lock = SPIN_LOCK_UNLOCKED;
+static void add_test_timer(struct multipath *m);
-static void submit_ios(struct bio *bio)
+static void queue_test_ios(struct multipath *m)
{
- struct bio *next;
+ queue_work(_kmpathd_wq, &m->test_pgroup);
+ add_test_timer(m);
+}
- while (bio) {
- next = bio->bi_next;
- bio->bi_next = NULL;
- generic_make_request(bio);
- bio = next;
+static void add_test_timer(struct multipath *m)
+{
+ if (m->test_interval) {
+ m->test_timer.function = (void (*)(unsigned long))queue_test_ios;
+ m->test_timer.data = (unsigned long)m;
+ m->test_timer.expires = m->test_interval;
+ add_timer(&m->test_timer);
}
}
@@ -320,13 +322,11 @@ static int __choose_path(struct multipat
struct priority_group *pg;
struct path *path = NULL;
- if (m->nr_valid_paths) {
- /* loop through the priority groups until we find a valid path. */
- list_for_each_entry (pg, &m->priority_groups, list) {
- path = pg->ps->type->select_path(pg->ps);
- if (path)
- break;
- }
+ /* loop through the priority groups until we find a valid path. */
+ list_for_each_entry (pg, &m->priority_groups, list) {
+ path = pg->ps->type->select_path(pg->ps);
+ if (path)
+ break;
}
m->current_path = path;
@@ -364,68 +364,31 @@ static int map_io(struct multipath *m, s
return 0;
}
-static void dispatch_failed_ios(struct multipath *m)
+static void dispatch_failed_ios(void *data)
{
+ struct multipath *m = (struct multipath *)data;
int r;
unsigned long flags;
struct bio *bio = NULL, *next;
spin_lock_irqsave(&m->lock, flags);
- if (m->nr_valid_paths || (m->nr_tested_paths == m->nr_paths))
- bio = bio_list_get(&m->failed_ios);
+ bio = bio_list_get(&m->failed_ios);
spin_unlock_irqrestore(&m->lock, flags);
-
while (bio) {
next = bio->bi_next;
bio->bi_next = NULL;
r = map_io(m, bio);
if (r)
- /*
- * This wont loop forever because the
- * end_io function will fail the ios if
- * we've tested all the paths.
- */
bio_io_error(bio, bio->bi_size);
-
else
generic_make_request(bio);
bio = next;
}
-}
-
-/*
- * Multipathd does this every time it runs, returning a sleep
- * duration hint.
- */
-static jiffy_t do_work(void)
-{
- unsigned long flags;
- struct multipath *m;
- unsigned interval = 0;
-
- spin_lock(&_mpath_lock);
- list_for_each_entry (m, &_mpaths, list) {
- dispatch_failed_ios(m);
- iterate_paths(m, test_path);
- submit_ios(bio_list_get(&m->test_ios));
-
- spin_lock_irqsave(&m->lock, flags);
- if (m->trigger_event) {
- dm_table_event(m->ti->table);
- m->trigger_event = 0;
- }
- spin_unlock_irqrestore(&m->lock, flags);
-
- interval = min_not_zero(interval, m->test_interval);
- }
- spin_unlock(&_mpath_lock);
blk_run_queues();
-
- return ((jiffy_t) interval) * HZ;
}
/*-----------------------------------------------------------------
@@ -681,15 +644,11 @@ static int multipath_ctr(struct dm_targe
__insert_priority_group(m, pg);
}
}
- m->nr_valid_paths = m->nr_paths;
+ add_test_timer(m);
ti->private = m;
m->ti = ti;
- spin_lock(&_mpath_lock);
- list_add(&m->list, &_mpaths);
- spin_unlock(&_mpath_lock);
-
return 0;
bad:
@@ -700,11 +659,6 @@ static int multipath_ctr(struct dm_targe
static void multipath_dtr(struct dm_target *ti)
{
struct multipath *m = (struct multipath *) ti->private;
-
- spin_lock(&_mpath_lock);
- list_del(&m->list);
- spin_unlock(&_mpath_lock);
-
free_multipath(m);
}
@@ -745,13 +699,6 @@ static int multipath_end_io(struct dm_ta
struct multipath *m = (struct multipath *) ti->private;
if (error) {
- spin_lock(&m->lock);
- if (!m->nr_valid_paths && (m->nr_tested_paths == m->nr_paths)) {
- spin_unlock(&m->lock);
- return -EIO;
- }
- spin_unlock(&m->lock);
-
path = find_path(m, bio->bi_bdev);
fail_path(path);
@@ -760,7 +707,7 @@ static int multipath_end_io(struct dm_ta
bio_list_add(&m->failed_ios, bio);
spin_unlock(&m->lock);
- dm_daemon_wake(&_kmpathd);
+ queue_work(_kmpathd_wq, &m->dispatch_failed);
return 1; /* io not complete */
}
@@ -887,8 +834,8 @@ int __init dm_multipath_init(void)
return r;
}
- r = dm_daemon_start(&_kmpathd, "kpathd", do_work);
- if (r) {
+ _kmpathd_wq = create_workqueue("kmpathd");
+ if (!_kmpathd_wq) {
/* FIXME: remove this */
dm_unregister_path_selectors();
dm_unregister_target(&multipath_target);
@@ -902,7 +849,7 @@ void __exit dm_multipath_exit(void)
{
int r;
- dm_daemon_stop(&_kmpathd);
+ destroy_workqueue(_kmpathd_wq);
dm_unregister_path_selectors();
r = dm_unregister_target(&multipath_target);
if (r < 0)