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authorJoe Thornber <ejt@redhat.com>2014-10-10 15:27:16 +0100
committerMike Snitzer <snitzer@redhat.com>2014-11-10 15:25:28 -0500
commit2d759a46b4d65e1392843cf9df7101897af87008 (patch)
tree7cca57c04d5d8e29ca7ae232fa52f2e8fa6883c3 /drivers/md/dm-bio-prison.c
parenta374bb217b449a00eb96d0584bb833a8b62b672a (diff)
dm thin: remap the bios in a cell immediately
This use of direct submission in process_prepared_mapping() reduces latency for submitting bios in a cell by avoiding adding those bios to the deferred list and waiting for the next iteration of the worker. But this direct submission exposes the potential for a race between releasing a cell and incrementing deferred set. Fix this by introducing dm_cell_visit_release() and refactoring inc_remap_and_issue_cell() accordingly. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-bio-prison.c')
-rw-r--r--drivers/md/dm-bio-prison.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c
index 90a56625245a..bbe22a5dc06b 100644
--- a/drivers/md/dm-bio-prison.c
+++ b/drivers/md/dm-bio-prison.c
@@ -241,6 +241,20 @@ void dm_cell_error(struct dm_bio_prison *prison,
}
EXPORT_SYMBOL_GPL(dm_cell_error);
+void dm_cell_visit_release(struct dm_bio_prison *prison,
+ void (*visit_fn)(void *, struct dm_bio_prison_cell *),
+ void *context,
+ struct dm_bio_prison_cell *cell)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&prison->lock, flags);
+ visit_fn(context, cell);
+ rb_erase(&cell->node, &prison->cells);
+ spin_unlock_irqrestore(&prison->lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_cell_visit_release);
+
/*----------------------------------------------------------------*/
#define DEFERRED_SET_SIZE 64