The target can set the function num_write_bios - dm will issue this
callback to ask the target how many bios does it want to receive.
This was intended for the dm-cache target, but it is not useable due to a
race condition (see the description of
e2e74d617eadc15f601983270c4f4a6935c5a943). num_write_bios is unused, so we
remove it.
Note that we deliberately leave the for loop in __clone_and_map_data_bio -
it will be used in the next patch.
Signed-off-by: Mikulas Patocka <mpato...@redhat.com>
---
drivers/md/dm.c | 6 ------
include/linux/device-mapper.h | 15 ---------------
2 files changed, 21 deletions(-)
Index: linux-3.18-rc1/drivers/md/dm.c
===================================================================
--- linux-3.18-rc1.orig/drivers/md/dm.c 2014-10-21 00:53:43.000000000 +0200
+++ linux-3.18-rc1/drivers/md/dm.c 2014-10-21 00:53:47.000000000 +0200
@@ -1433,12 +1433,6 @@ static void __clone_and_map_data_bio(str
unsigned target_bio_nr;
unsigned num_target_bios = 1;
- /*
- * Does the target want to receive duplicate copies of the bio?
- */
- if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
- num_target_bios = ti->num_write_bios(ti, bio);
-
for (target_bio_nr = 0; target_bio_nr < num_target_bios;
target_bio_nr++) {
tio = alloc_tio(ci, ti, target_bio_nr);
tio->len_ptr = len;
Index: linux-3.18-rc1/include/linux/device-mapper.h
===================================================================
--- linux-3.18-rc1.orig/include/linux/device-mapper.h 2014-10-21
00:53:43.000000000 +0200
+++ linux-3.18-rc1/include/linux/device-mapper.h 2014-10-21
00:53:47.000000000 +0200
@@ -184,14 +184,6 @@ struct target_type {
#define DM_TARGET_IMMUTABLE 0x00000004
#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
-/*
- * Some targets need to be sent the same WRITE bio severals times so
- * that they can send copies of it to different devices. This function
- * examines any supplied bio and returns the number of copies of it the
- * target requires.
- */
-typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio
*bio);
-
struct dm_target {
struct dm_table *table;
struct target_type *type;
@@ -231,13 +223,6 @@ struct dm_target {
*/
unsigned per_bio_data_size;
- /*
- * If defined, this function is called to find out how many
- * duplicate bios should be sent to the target when writing
- * data.
- */
- dm_num_write_bios_fn num_write_bios;
-
/* target specific data */
void *private;
--
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