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Go Back   Linux Archive > Redhat > Device-mapper Development

 
 
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Old 02-29-2012, 01:50 PM
Mike Snitzer
 
Default dm thin: tidy up the cell_release functions

From: Joe Thornber <ejt@redhat.com>

Clarify what is expected during each cell release by introducing
variants of __cell_release.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm-thin.c | 52 +++++++++++++++++++++++++++++++++----------------
1 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 920304e..f796afb 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -306,22 +306,45 @@ static void cell_release(struct cell *cell, struct bio_list *bios)
* bio may be in the cell. This function releases the cell, and also does
* a sanity check.
*/
+static void __cell_release_singleton(struct cell *cell, struct bio *bio)
+{
+ hlist_del(&cell->list);
+ BUG_ON(cell->holder != bio);
+ BUG_ON(!bio_list_empty(&cell->bios));
+}
+
static void cell_release_singleton(struct cell *cell, struct bio *bio)
{
- struct bio_prison *prison = cell->prison;
- struct bio_list bios;
- struct bio *b;
unsigned long flags;
-
- bio_list_init(&bios);
+ struct bio_prison *prison = cell->prison;

spin_lock_irqsave(&prison->lock, flags);
- __cell_release(cell, &bios);
+ __cell_release_singleton(cell, bio);
spin_unlock_irqrestore(&prison->lock, flags);
+}
+
+/*
+ * Sometimes we don't want the holder, just the additional bios.
+ */
+static void __cell_release_no_holder(struct cell *cell, struct bio_list *inmates)
+{
+ struct bio_prison *prison = cell->prison;

- b = bio_list_pop(&bios);
- BUG_ON(b != bio);
- BUG_ON(!bio_list_empty(&bios));
+ hlist_del(&cell->list);
+ if (inmates)
+ bio_list_merge(inmates, &cell->bios);
+
+ mempool_free(cell, prison->cell_pool);
+}
+
+static void cell_release_no_holder(struct cell *cell, struct bio_list *inmates)
+{
+ unsigned long flags;
+ struct bio_prison *prison = cell->prison;
+
+ spin_lock_irqsave(&prison->lock, flags);
+ __cell_release_no_holder(cell, inmates);
+ spin_unlock_irqrestore(&prison->lock, flags);
}

static void cell_error(struct cell *cell)
@@ -803,21 +826,16 @@ static void cell_defer(struct thin_c *tc, struct cell *cell,
* Same as cell_defer above, except it omits one particular detainee,
* a write bio that covers the block and has already been processed.
*/
-static void cell_defer_except(struct thin_c *tc, struct cell *cell,
- struct bio *exception)
+static void cell_defer_except(struct thin_c *tc, struct cell *cell)
{
struct bio_list bios;
- struct bio *bio;
struct pool *pool = tc->pool;
unsigned long flags;

bio_list_init(&bios);
- cell_release(cell, &bios);

spin_lock_irqsave(&pool->lock, flags);
- while ((bio = bio_list_pop(&bios)))
- if (bio != exception)
- bio_list_add(&pool->deferred_bios, bio);
+ cell_release_no_holder(cell, &pool->deferred_bios);
spin_unlock_irqrestore(&pool->lock, flags);

wake_worker(pool);
@@ -857,7 +875,7 @@ static void process_prepared_mapping(struct new_mapping *m)
* the bios in the cell.
*/
if (bio) {
- cell_defer_except(tc, m->cell, bio);
+ cell_defer_except(tc, m->cell);
bio_endio(bio, 0);
} else
cell_defer(tc, m->cell, m->data_block);
--
1.7.1

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