dm bio prison: add dm_cell_promote_or_release()

[cascardo/linux.git] / drivers / md / dm-bio-prison.c

diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c
index be06530..cd6d1d2 100644 (file)
--- a/drivers/md/dm-bio-prison.c
+++ b/drivers/md/dm-bio-prison.c
@@ -255,6 +255,32 @@ void dm_cell_visit_release(struct dm_bio_prison *prison,
 }
 EXPORT_SYMBOL_GPL(dm_cell_visit_release);
 
+static int __promote_or_release(struct dm_bio_prison *prison,
+                               struct dm_bio_prison_cell *cell)
+{
+       if (bio_list_empty(&cell->bios)) {
+               rb_erase(&cell->node, &prison->cells);
+               return 1;
+       }
+
+       cell->holder = bio_list_pop(&cell->bios);
+       return 0;
+}
+
+int dm_cell_promote_or_release(struct dm_bio_prison *prison,
+                              struct dm_bio_prison_cell *cell)
+{
+       int r;
+       unsigned long flags;
+
+       spin_lock_irqsave(&prison->lock, flags);
+       r = __promote_or_release(prison, cell);
+       spin_unlock_irqrestore(&prison->lock, flags);
+
+       return r;
+}
+EXPORT_SYMBOL_GPL(dm_cell_promote_or_release);
+
 /*----------------------------------------------------------------*/
 
 #define DEFERRED_SET_SIZE 64