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authorMike Snitzer <snitzer@redhat.com>2012-07-27 15:08:00 +0100
committerAlasdair G Kergon <agk@redhat.com>2012-07-27 15:08:00 +0100
commit542f90381422676544382d4071ba44a2de90a0c1 (patch)
tree0eae6798ab2fdef68a0eb1ea5ac14f3cc3ffb740 /include/linux/device-mapper.h
parent1df05483d758ea43abc375869fbe06be506ba827 (diff)
dm: support non power of two target max_io_len
Remove the restriction that limits a target's specified maximum incoming I/O size to be a power of 2. Rename this setting from 'split_io' to the less-ambiguous 'max_io_len'. Change it from sector_t to uint32_t, which is plenty big enough, and introduce a wrapper function dm_set_target_max_io_len() to set it. Use sector_div() to process it now that it is not necessarily a power of 2. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h9
1 files changed, 7 insertions, 2 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index d70cbb2ada25..b19c1e189a68 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -186,8 +186,8 @@ struct dm_target {
sector_t begin;
sector_t len;
- /* Always a power of 2 */
- sector_t split_io;
+ /* If non-zero, maximum size of I/O submitted to a target. */
+ uint32_t max_io_len;
/*
* A number of zero-length barrier requests that will be submitted
@@ -358,6 +358,11 @@ void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callback
int dm_table_complete(struct dm_table *t);
/*
+ * Target may require that it is never sent I/O larger than len.
+ */
+int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
+
+/*
* Table reference counting.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md);