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authorKiyoshi Ueda <k-ueda@ct.jp.nec.com>2009-01-06 03:05:07 +0000
committerAlasdair G Kergon <agk@redhat.com>2009-01-06 03:05:07 +0000
commit7d76345da6ed3927c9cbf5d3f7a7021e8bba7374 (patch)
treed0b470dd1a55dfffb27ffa012e4a5afebd133495
parent8fbf26ad5b16ad3a826ca7fe3e86700420abed1f (diff)
downloadblackbird-op-linux-7d76345da6ed3927c9cbf5d3f7a7021e8bba7374.tar.gz
blackbird-op-linux-7d76345da6ed3927c9cbf5d3f7a7021e8bba7374.zip
dm request: extend target interface
This patch adds the following target interfaces for request-based dm. map_rq : for mapping a request rq_end_io : for finishing a request busy : for avoiding performance regression from bio-based dm. Target can tell dm core not to map requests now, and that may help requests in the block layer queue to be bigger by I/O merging. In bio-based dm, this behavior is done by device drivers managing the block layer queue. But in request-based dm, dm core has to do that since dm core manages the block layer queue. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
-rw-r--r--include/linux/device-mapper.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 89ff2df40240..c1ba76c7c0e5 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -45,6 +45,8 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti);
*/
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
union map_info *map_context);
+typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
+ union map_info *map_context);
/*
* Returns:
@@ -57,6 +59,9 @@ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
typedef int (*dm_endio_fn) (struct dm_target *ti,
struct bio *bio, int error,
union map_info *map_context);
+typedef int (*dm_request_endio_fn) (struct dm_target *ti,
+ struct request *clone, int error,
+ union map_info *map_context);
typedef void (*dm_flush_fn) (struct dm_target *ti);
typedef void (*dm_presuspend_fn) (struct dm_target *ti);
@@ -75,6 +80,13 @@ typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
struct bio_vec *biovec, int max_size);
+/*
+ * Returns:
+ * 0: The target can handle the next I/O immediately.
+ * 1: The target can't handle the next I/O immediately.
+ */
+typedef int (*dm_busy_fn) (struct dm_target *ti);
+
void dm_error(const char *message);
/*
@@ -107,7 +119,9 @@ struct target_type {
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
+ dm_map_request_fn map_rq;
dm_endio_fn end_io;
+ dm_request_endio_fn rq_end_io;
dm_flush_fn flush;
dm_presuspend_fn presuspend;
dm_postsuspend_fn postsuspend;
@@ -117,6 +131,7 @@ struct target_type {
dm_message_fn message;
dm_ioctl_fn ioctl;
dm_merge_fn merge;
+ dm_busy_fn busy;
};
struct io_restrictions {
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