X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fmd%2Fdm-cache-policy.h;h=05db56eedb6a761ae42d3f1c09cdd803c540d8c0;hb=ec568fdb37d280371733cab5e9fad030557f6921;hp=f50fe360c5462928522101c2497ee0ef57542cf0;hpb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;p=kvmfornfv.git

diff --git a/kernel/drivers/md/dm-cache-policy.h b/kernel/drivers/md/dm-cache-policy.h
index f50fe360c..05db56eed 100644
--- a/kernel/drivers/md/dm-cache-policy.h
+++ b/kernel/drivers/md/dm-cache-policy.h
@@ -69,6 +69,18 @@ enum policy_operation {
 	POLICY_REPLACE
 };
 
+/*
+ * When issuing a POLICY_REPLACE the policy needs to make a callback to
+ * lock the block being demoted.  This doesn't need to occur during a
+ * writeback operation since the block remains in the cache.
+ */
+struct policy_locker;
+typedef int (*policy_lock_fn)(struct policy_locker *l, dm_oblock_t oblock);
+
+struct policy_locker {
+	policy_lock_fn fn;
+};
+
 /*
  * This is the instruction passed back to the core target.
  */
@@ -122,7 +134,8 @@ struct dm_cache_policy {
 	 */
 	int (*map)(struct dm_cache_policy *p, dm_oblock_t oblock,
 		   bool can_block, bool can_migrate, bool discarded_oblock,
-		   struct bio *bio, struct policy_result *result);
+		   struct bio *bio, struct policy_locker *locker,
+		   struct policy_result *result);
 
 	/*
 	 * Sometimes we want to see if a block is in the cache, without
@@ -165,7 +178,9 @@ struct dm_cache_policy {
 	int (*remove_cblock)(struct dm_cache_policy *p, dm_cblock_t cblock);
 
 	/*
-	 * Provide a dirty block to be written back by the core target.
+	 * Provide a dirty block to be written back by the core target.  If
+	 * critical_only is set then the policy should only provide work if
+	 * it urgently needs it.
 	 *
 	 * Returns:
 	 *
@@ -173,7 +188,8 @@ struct dm_cache_policy {
 	 *
 	 * -ENODATA: no dirty blocks available
 	 */
-	int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock);
+	int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock,
+			      bool critical_only);
 
 	/*
 	 * How full is the cache?
@@ -184,16 +200,16 @@ struct dm_cache_policy {
 	 * Because of where we sit in the block layer, we can be asked to
 	 * map a lot of little bios that are all in the same block (no
 	 * queue merging has occurred).  To stop the policy being fooled by
-	 * these the core target sends regular tick() calls to the policy.
+	 * these, the core target sends regular tick() calls to the policy.
 	 * The policy should only count an entry as hit once per tick.
 	 */
-	void (*tick)(struct dm_cache_policy *p);
+	void (*tick)(struct dm_cache_policy *p, bool can_block);
 
 	/*
 	 * Configuration.
 	 */
-	int (*emit_config_values)(struct dm_cache_policy *p,
-				  char *result, unsigned maxlen);
+	int (*emit_config_values)(struct dm_cache_policy *p, char *result,
+				  unsigned maxlen, ssize_t *sz_ptr);
 	int (*set_config_value)(struct dm_cache_policy *p,
 				const char *key, const char *value);