Merge branch 'next' into for-linus

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / md / dm-bio-prison.h

diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h
index 53d1a7a84e2fec12da0bccfa23e0a86fb01fcbfb..3f833190eadf6b3a275951a71558a583811d37ad 100644 (file)
--- a/drivers/md/dm-bio-prison.h
+++ b/drivers/md/dm-bio-prison.h
@@ -22,7 +22,6 @@
  * subsequently unlocked the bios become available.
  */
 struct dm_bio_prison;
-struct dm_bio_prison_cell;
 
 /* FIXME: this needs to be more abstract */
 struct dm_cell_key {
@@ -31,21 +30,62 @@ struct dm_cell_key {
        dm_block_t block;
 };
 
+/*
+ * Treat this as opaque, only in header so callers can manage allocation
+ * themselves.
+ */
+struct dm_bio_prison_cell {
+       struct hlist_node list;
+       struct dm_cell_key key;
+       struct bio *holder;
+       struct bio_list bios;
+};
+
 struct dm_bio_prison *dm_bio_prison_create(unsigned nr_cells);
 void dm_bio_prison_destroy(struct dm_bio_prison *prison);
 
 /*
- * This may block if a new cell needs allocating.  You must ensure that
- * cells will be unlocked even if the calling thread is blocked.
+ * These two functions just wrap a mempool.  This is a transitory step:
+ * Eventually all bio prison clients should manage their own cell memory.
  *
- * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
+ * Like mempool_alloc(), dm_bio_prison_alloc_cell() can only fail if called
+ * in interrupt context or passed GFP_NOWAIT.
  */
-int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key,
-                 struct bio *inmate, struct dm_bio_prison_cell **ref);
+struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison,
+                                                   gfp_t gfp);
+void dm_bio_prison_free_cell(struct dm_bio_prison *prison,
+                            struct dm_bio_prison_cell *cell);
 
-void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios);
-void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates);
-void dm_cell_error(struct dm_bio_prison_cell *cell);
+/*
+ * Creates, or retrieves a cell for the given key.
+ *
+ * Returns 1 if pre-existing cell returned, zero if new cell created using
+ * @cell_prealloc.
+ */
+int dm_get_cell(struct dm_bio_prison *prison,
+               struct dm_cell_key *key,
+               struct dm_bio_prison_cell *cell_prealloc,
+               struct dm_bio_prison_cell **cell_result);
+
+/*
+ * An atomic op that combines retrieving a cell, and adding a bio to it.
+ *
+ * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
+ */
+int dm_bio_detain(struct dm_bio_prison *prison,
+                 struct dm_cell_key *key,
+                 struct bio *inmate,
+                 struct dm_bio_prison_cell *cell_prealloc,
+                 struct dm_bio_prison_cell **cell_result);
+
+void dm_cell_release(struct dm_bio_prison *prison,
+                    struct dm_bio_prison_cell *cell,
+                    struct bio_list *bios);
+void dm_cell_release_no_holder(struct dm_bio_prison *prison,
+                              struct dm_bio_prison_cell *cell,
+                              struct bio_list *inmates);
+void dm_cell_error(struct dm_bio_prison *prison,
+                  struct dm_bio_prison_cell *cell);
 
 /*----------------------------------------------------------------*/