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authorMike Snitzer <snitzer@redhat.com>2016-05-25 04:16:51 +0300
committerMike Snitzer <snitzer@redhat.com>2016-06-10 22:16:02 +0300
commite83068a5faafb8ca65d3b58bd1e1e3959ce1ddce (patch)
tree9158ec7acad94d7035153f84e8ff53205caf7315 /include/linux/device-mapper.h
parentbf661be1fcf9b1da8abc81a56ff41ce5964ce896 (diff)
downloadlinux-e83068a5faafb8ca65d3b58bd1e1e3959ce1ddce.tar.xz
dm mpath: add optional "queue_mode" feature
Allow a user to specify an optional feature 'queue_mode <mode>' where <mode> may be "bio", "rq" or "mq" -- which corresponds to bio-based, request_fn rq-based, and blk-mq rq-based respectively. If the queue_mode feature isn't specified the default for the "multipath" target is still "rq" but if dm_mod.use_blk_mq is set to Y it'll default to mode "mq". This new queue_mode feature introduces the ability for each multipath device to have its own queue_mode (whereas before this feature all multipath devices effectively had to have the same queue_mode). This commit also goes a long way to eliminate the awkward (ab)use of DM_TYPE_*, the associated filter_md_type() and other relatively fragile and difficult to maintain code. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 0830c9e86f0d..2ce339212b6e 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -19,6 +19,14 @@ struct dm_table;
struct mapped_device;
struct bio_vec;
+/*
+ * Type of table, mapped_device's mempool and request_queue
+ */
+#define DM_TYPE_NONE 0
+#define DM_TYPE_BIO_BASED 1
+#define DM_TYPE_REQUEST_BASED 2
+#define DM_TYPE_MQ_REQUEST_BASED 3
+
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
union map_info {
@@ -444,6 +452,14 @@ int dm_table_add_target(struct dm_table *t, const char *type,
void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
/*
+ * Target can use this to set the table's type.
+ * Can only ever be called from a target's ctr.
+ * Useful for "hybrid" target (supports both bio-based
+ * and request-based).
+ */
+void dm_table_set_type(struct dm_table *t, unsigned type);
+
+/*
* Finally call this to make the table ready for use.
*/
int dm_table_complete(struct dm_table *t);