From 123d87d553e26f67e7be318c97c971b6b5fb1daa Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 23 Aug 2019 09:55:26 -0400 Subject: 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: Mikulas Patocka Signed-off-by: Mike Snitzer --- drivers/md/dm-table.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'drivers/md/dm-table.c') diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 8820931ec7d2..52e049554f5c 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -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); -- cgit v1.2.3