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dm: refactor deferred bio_list processing

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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>
This commit is contained in:
Milan Broz 2008-02-08 02:10:22 +00:00 committed by Alasdair G Kergon
parent 6ed7ade896
commit 6d6f10df89
1 changed files with 29 additions and 38 deletions
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57
drivers/md/dm.c
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@ -1262,19 +1262,27 @@ EXPORT_SYMBOL_GPL(dm_put);
/*
* 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 @@ static void unlock_fs(struct mapped_device *md)
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;
@ -1378,17 +1384,17 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
r = -ENOMEM;
goto flush_and_out;
}
}
/*
* Flush I/O to the device.
* noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os.
* Flush I/O to the device. noflush supersedes do_lockfs,
* because lock_fs() needs to flush I/Os.
*/
if (do_lockfs && !noflush) {
if (do_lockfs) {
r = lock_fs(md);
if (r)
goto out;
}
}
/*
* First we set the BLOCK_IO flag so no more ios will be mapped.
@ -1421,20 +1427,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
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 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
* 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_suspend(struct mapped_device *md, unsigned suspend_flags)
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 @@ int dm_resume(struct mapped_device *md)
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);