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authorMikulas Patocka <mpatocka@redhat.com>2012-12-21 20:23:38 +0000
committerAlasdair G Kergon <agk@redhat.com>2012-12-21 20:23:38 +0000
commitc0820cf5ad09522bdd9ff68e84841a09c9f339d8 (patch)
tree04817d6d9a7d213ac96d1e014a9714f8f29ff07a /drivers/md/dm.h
parent70d6c400acc386ea910c77318688541fc32e7ce8 (diff)
downloadlinux-c0820cf5ad09522bdd9ff68e84841a09c9f339d8.tar.bz2
dm: introduce per_bio_data
Introduce a field per_bio_data_size in struct dm_target. Targets can set this field in the constructor. If a target sets this field to a non-zero value, "per_bio_data_size" bytes of auxiliary data are allocated for each bio submitted to the target. These data can be used for any purpose by the target and help us improve performance by removing some per-target mempools. Per-bio data is accessed with dm_per_bio_data. The argument data_size must be the same as the value per_bio_data_size in dm_target. If the target has a pointer to per_bio_data, it can get a pointer to the bio with dm_bio_from_per_bio_data() function (data_size must be the same as the value passed to dm_per_bio_data). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm.h')
-rw-r--r--drivers/md/dm.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 6a99fefaa743..45b97da1bd06 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -159,7 +159,7 @@ void dm_kcopyd_exit(void);
/*
* Mempool operations
*/
-struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity);
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size);
void dm_free_md_mempools(struct dm_md_mempools *pools);
#endif