Commit 123d87d5 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm: make dm_table_find_target return NULL 



Currently, if we pass too high sector number to dm_table_find_target, it
returns zeroed dm_target structure and callers test if the structure is
zeroed with the macro dm_target_is_valid.

However, returning NULL is common practice to indicate errors.

This patch refactors the dm code, so that dm_table_find_target returns
NULL and its callers test the returned value for NULL. The macro
dm_target_is_valid is deleted. In alloc_targets, we no longer allocate an
extra zeroed target.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 1cfd5d33

drivers/md/dm-ioctl.c

+1 −1
Original line number Diff line number Diff line
@@ -1592,7 +1592,7 @@ static int target_message(struct file *filp, struct dm_ioctl *param, size_t para 
	}



	ti = dm_table_find_target(table, tmsg->sector);

	if (!dm_target_is_valid(ti)) {

	if (!ti) {

		DMWARN("Target message sector outside device.");

		r = -EINVAL;

	} else if (ti->type->message)

drivers/md/dm-table.c

+3 −5
Original line number Diff line number Diff line
@@ -163,10 +163,8 @@ static int alloc_targets(struct dm_table *t, unsigned int num) 


	/*

	 * Allocate both the target array and offset array at once.

	 * Append an empty entry to catch sectors beyond the end of

	 * the device.

	 */

	n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +

	n_highs = (sector_t *) dm_vcalloc(num, sizeof(struct dm_target) +

					  sizeof(sector_t));

	if (!n_highs)

		return -ENOMEM;
@@ -1359,7 +1357,7 @@ struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index) 
/*

 * Search the btree for the correct target.

 *

 * Caller should check returned pointer with dm_target_is_valid()

 * Caller should check returned pointer for NULL

 * to trap I/O beyond end of device.

 */

struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
@@ -1368,7 +1366,7 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector) 
	sector_t *node;



	if (unlikely(sector >= dm_table_get_size(t)))

		return &t->targets[t->num_targets];

		return NULL;



	for (l = 0; l < t->depth; l++) {

		n = get_child(n, k);

drivers/md/dm.c

+4 −4
Original line number Diff line number Diff line
@@ -457,7 +457,7 @@ static int dm_blk_report_zones(struct gendisk *disk, sector_t sector, 
		return -EIO;



	tgt = dm_table_find_target(map, sector);

	if (!dm_target_is_valid(tgt)) {

	if (!tgt) {

		ret = -EIO;

		goto out;

	}
@@ -1072,7 +1072,7 @@ static struct dm_target *dm_dax_get_live_target(struct mapped_device *md, 
		return NULL;



	ti = dm_table_find_target(map, sector);

	if (!dm_target_is_valid(ti))

	if (!ti)

		return NULL;



	return ti;
@@ -1572,7 +1572,7 @@ static int __split_and_process_non_flush(struct clone_info *ci) 
	int r;



	ti = dm_table_find_target(ci->map, ci->sector);

	if (!dm_target_is_valid(ti))

	if (!ti)

		return -EIO;



	if (__process_abnormal_io(ci, ti, &r))
@@ -1748,7 +1748,7 @@ static blk_qc_t dm_process_bio(struct mapped_device *md, 


	if (!ti) {

		ti = dm_table_find_target(map, bio->bi_iter.bi_sector);

		if (unlikely(!ti || !dm_target_is_valid(ti))) {

		if (unlikely(!ti)) {

			bio_io_error(bio);

			return ret;

		}

drivers/md/dm.h

+0 −5
Original line number Diff line number Diff line
@@ -85,11 +85,6 @@ struct target_type *dm_get_immutable_target_type(struct mapped_device *md); 


int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t);



/*

 * To check the return value from dm_table_find_target().

 */

#define dm_target_is_valid(t) ((t)->table)



/*

 * To check whether the target type is bio-based or not (request-based).

 */

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