From 542f90381422676544382d4071ba44a2de90a0c1 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Fri, 27 Jul 2012 15:08:00 +0100 Subject: 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 Signed-off-by: Alasdair G Kergon --- include/linux/device-mapper.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'include/linux/device-mapper.h') 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 @@ -357,6 +357,11 @@ 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. */ -- cgit v1.2.3