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| author |   Mikulas Patocka <mpatocka@redhat.com> | 2019-08-23 09:55:26 -0400 |
|---|---|---|
| committer |   Mike Snitzer <snitzer@redhat.com> | 2019-08-23 10:13:12 -0400 |
| commit | 123d87d553e26f67e7be318c97c971b6b5fb1daa (patch) | |
| tree | 874e61dd6809114c3b5186c2d7e0fc25a43b3662 /drivers/md/dm-table.c | |
| parent | dm table: fix invalid memory accesses with too high sector number (diff) | |
| download | linux-dev-123d87d553e26f67e7be318c97c971b6b5fb1daa.tar.xz linux-dev-123d87d553e26f67e7be318c97c971b6b5fb1daa.zip | |
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 <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | drivers/md/dm-table.c | 8 |
1 files changed, 3 insertions, 5 deletions
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); |