===================================================================
@@ -102,15 +102,18 @@ struct dm_snapshot {
spinlock_t tracked_chunk_lock;
struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
- /* Merge operation failed if this is set */
- int merge_failed;
+ /* Wait for events based on state bits */
+ unsigned long bits;
/* Merge operation is in progress */
- int merge_running;
+#define MERGE_RUNNING 0
/* It is requested to shut down merging */
/* Cleared back to 0 when the merging is stopped */
- int merge_shutdown;
+#define SHUTDOWN_MERGE 1
+
+ /* Merge operation failed if this is set */
+ int merge_failed;
/* Merging this area --- block any writes */
chunk_t merge_write_interlock;
@@ -776,8 +779,8 @@ static void snapshot_merge_process(struc
struct dm_io_region src, dest;
sector_t io_size;
- BUG_ON(!s->merge_running);
- if (s->merge_shutdown)
+ BUG_ON(!test_bit(MERGE_RUNNING, &s->bits));
+ if (unlikely(test_bit(SHUTDOWN_MERGE, &s->bits)))
goto shut;
if (!s->valid) {
@@ -849,7 +852,9 @@ test_again:
return;
shut:
- s->merge_running = 0;
+ clear_bit_unlock(MERGE_RUNNING, &s->bits);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&s->bits, MERGE_RUNNING);
}
/* This function drops s->lock */
@@ -931,15 +936,21 @@ shut:
down_write(&s->lock);
s->merge_failed = 1;
release_write_interlock(s, 1);
- s->merge_running = 0;
+ clear_bit_unlock(MERGE_RUNNING, &s->bits);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&s->bits, MERGE_RUNNING);
}
static void start_merge(struct dm_snapshot *s)
{
- if (!s->merge_running && !s->merge_shutdown) {
- s->merge_running = 1;
+ if (!test_and_set_bit(MERGE_RUNNING, &s->bits))
snapshot_merge_process(s);
- }
+}
+
+static int wait_schedule(void *ptr)
+{
+ schedule();
+ return 0;
}
/*
@@ -947,11 +958,10 @@ static void start_merge(struct dm_snapsh
*/
static void stop_merge(struct dm_snapshot *s)
{
- while (s->merge_running) {
- s->merge_shutdown = 1;
- msleep(1);
- }
- s->merge_shutdown = 0;
+ set_bit(SHUTDOWN_MERGE, &s->bits);
+ wait_on_bit(&s->bits, MERGE_RUNNING, wait_schedule,
+ TASK_UNINTERRUPTIBLE);
+ clear_bit(SHUTDOWN_MERGE, &s->bits);
}
/*
@@ -1018,9 +1028,8 @@ static int snapshot_ctr(struct dm_target
init_rwsem(&s->lock);
INIT_LIST_HEAD(&s->list);
spin_lock_init(&s->pe_lock);
+ s->bits = 0;
s->merge_failed = 0;
- s->merge_running = 0;
- s->merge_shutdown = 0;
s->merge_write_interlock = 0;
s->merge_write_interlock_n = 0;
bio_list_init(&s->merge_write_list);