dm: refactor deferred bio_list processing
Refactor deferred bio_list processing.
- use separate _merge_pushback_list function
- move deferred bio list pick up to flush function
- use bio_list_pop instead of bio_list_get
- simplify noflush flag use
No real functional change in this patch.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 52427e1..c1ad7d7 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1262,19 +1262,27 @@
/*
* Process the deferred bios
*/
-static void __flush_deferred_io(struct mapped_device *md, struct bio *c)
+static void __flush_deferred_io(struct mapped_device *md)
{
- struct bio *n;
+ struct bio *c;
- while (c) {
- n = c->bi_next;
- c->bi_next = NULL;
+ while ((c = bio_list_pop(&md->deferred))) {
if (__split_bio(md, c))
bio_io_error(c);
- c = n;
}
}
+static void __merge_pushback_list(struct mapped_device *md)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&md->pushback_lock, flags);
+ clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+ bio_list_merge_head(&md->deferred, &md->pushback);
+ bio_list_init(&md->pushback);
+ spin_unlock_irqrestore(&md->pushback_lock, flags);
+}
+
/*
* Swap in a new table (destroying old one).
*/
@@ -1346,9 +1354,7 @@
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
- unsigned long flags;
DECLARE_WAITQUEUE(wait, current);
- struct bio *def;
int r = -EINVAL;
int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
@@ -1378,16 +1384,16 @@
r = -ENOMEM;
goto flush_and_out;
}
- }
- /*
- * Flush I/O to the device.
- * noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os.
- */
- if (do_lockfs && !noflush) {
- r = lock_fs(md);
- if (r)
- goto out;
+ /*
+ * Flush I/O to the device. noflush supersedes do_lockfs,
+ * because lock_fs() needs to flush I/Os.
+ */
+ if (do_lockfs) {
+ r = lock_fs(md);
+ if (r)
+ goto out;
+ }
}
/*
@@ -1421,20 +1427,14 @@
down_write(&md->io_lock);
remove_wait_queue(&md->wait, &wait);
- if (noflush) {
- spin_lock_irqsave(&md->pushback_lock, flags);
- clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
- bio_list_merge_head(&md->deferred, &md->pushback);
- bio_list_init(&md->pushback);
- spin_unlock_irqrestore(&md->pushback_lock, flags);
- }
+ if (noflush)
+ __merge_pushback_list(md);
/* were we interrupted ? */
r = -EINTR;
if (atomic_read(&md->pending)) {
clear_bit(DMF_BLOCK_IO, &md->flags);
- def = bio_list_get(&md->deferred);
- __flush_deferred_io(md, def);
+ __flush_deferred_io(md);
up_write(&md->io_lock);
unlock_fs(md);
goto out; /* pushback list is already flushed, so skip flush */
@@ -1454,15 +1454,8 @@
* flush them before return.
*/
down_write(&md->io_lock);
-
- spin_lock_irqsave(&md->pushback_lock, flags);
- clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
- bio_list_merge_head(&md->deferred, &md->pushback);
- bio_list_init(&md->pushback);
- spin_unlock_irqrestore(&md->pushback_lock, flags);
-
- def = bio_list_get(&md->deferred);
- __flush_deferred_io(md, def);
+ __merge_pushback_list(md);
+ __flush_deferred_io(md);
up_write(&md->io_lock);
}
@@ -1482,7 +1475,6 @@
int dm_resume(struct mapped_device *md)
{
int r = -EINVAL;
- struct bio *def;
struct dm_table *map = NULL;
mutex_lock(&md->suspend_lock);
@@ -1500,8 +1492,7 @@
down_write(&md->io_lock);
clear_bit(DMF_BLOCK_IO, &md->flags);
- def = bio_list_get(&md->deferred);
- __flush_deferred_io(md, def);
+ __flush_deferred_io(md);
up_write(&md->io_lock);
unlock_fs(md);