Commit f31c21e4 authored by NeilBrown's avatar NeilBrown Committed by Mike Snitzer
Browse files

dm: remove unused 'num_write_bios' target interface 



No DM target provides num_write_bios and none has since dm-cache's
brief use in 2013.

Having the possibility of num_write_bios > 1 complicates bio
allocation.  So remove the interface and assume there is only one bio
needed.

If a target ever needs more, it must provide a suitable bioset and
allocate itself based on its particular needs.

Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 18a25da8

drivers/md/dm.c

+10 −20
Original line number Diff line number Diff line
@@ -1323,28 +1323,18 @@ static int __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti, 
{

	struct bio *bio = ci->bio;

	struct dm_target_io *tio;

	unsigned target_bio_nr;

	unsigned num_target_bios = 1;

	int r = 0;



	/*

	 * 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);

	int r;



	for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {

		tio = alloc_tio(ci, ti, target_bio_nr);

	tio = alloc_tio(ci, ti, 0);

	tio->len_ptr = len;

	r = clone_bio(tio, bio, sector, *len);

	if (r < 0) {

		free_tio(tio);

			break;

		return r;

	}

	__map_bio(tio);

	}



	return r;

	return 0;

}



typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);

include/linux/device-mapper.h

+0 −15
Original line number Diff line number Diff line
@@ -220,14 +220,6 @@ struct target_type { 
#define DM_TARGET_WILDCARD		0x00000008

#define dm_target_is_wildcard(type)	((type)->features & DM_TARGET_WILDCARD)



/*

 * 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);



/*

 * A target implements own bio data integrity.

 */
@@ -291,13 +283,6 @@ struct dm_target { 
	 */

	unsigned per_io_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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