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dm zoned: target: use refcount_t for dm zoned reference counters

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The API surrounding refcount_t should be used in place of atomic_t
when variables are being used as reference counters.  This API can
prevent issues such as counter overflows and use-after-free
conditions.  Within the dm zoned target stack, the atomic_t API is
used for bioctx->ref and cw->refcount.  Change these to use
refcount_t, avoiding the issues mentioned.

Signed-off-by: John Pittman <jpittman@redhat.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
John Pittman 2018-08-23 13:35:57 -04:00 committed by Mike Snitzer
parent 22d4c291f5
commit 092b564876
1 changed files with 10 additions and 10 deletions
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20
drivers/md/dm-zoned-target.c
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@ -19,7 +19,7 @@ struct dmz_bioctx {
struct dmz_target *target;
struct dm_zone *zone;
struct bio *bio;
atomic_t ref;
refcount_t ref;
blk_status_t status;
};
@ -28,7 +28,7 @@ struct dmz_bioctx {
*/
struct dm_chunk_work {
struct work_struct work;
atomic_t refcount;
refcount_t refcount;
struct dmz_target *target;
unsigned int chunk;
struct bio_list bio_list;
@ -115,7 +115,7 @@ static int dmz_submit_read_bio(struct dmz_target *dmz, struct dm_zone *zone,
if (nr_blocks == dmz_bio_blocks(bio)) {
/* Setup and submit the BIO */
bio->bi_iter.bi_sector = sector;
atomic_inc(&bioctx->ref);
refcount_inc(&bioctx->ref);
generic_make_request(bio);
return 0;
}
@ -134,7 +134,7 @@ static int dmz_submit_read_bio(struct dmz_target *dmz, struct dm_zone *zone,
bio_advance(bio, clone->bi_iter.bi_size);
/* Submit the clone */
atomic_inc(&bioctx->ref);
refcount_inc(&bioctx->ref);
generic_make_request(clone);
return 0;
@ -240,7 +240,7 @@ static void dmz_submit_write_bio(struct dmz_target *dmz, struct dm_zone *zone,
/* Setup and submit the BIO */
bio_set_dev(bio, dmz->dev->bdev);
bio->bi_iter.bi_sector = dmz_start_sect(dmz->metadata, zone) + dmz_blk2sect(chunk_block);
atomic_inc(&bioctx->ref);
refcount_inc(&bioctx->ref);
generic_make_request(bio);
if (dmz_is_seq(zone))
@ -456,7 +456,7 @@ out:
*/
static inline void dmz_get_chunk_work(struct dm_chunk_work *cw)
{
atomic_inc(&cw->refcount);
refcount_inc(&cw->refcount);
}
/*
@ -465,7 +465,7 @@ static inline void dmz_get_chunk_work(struct dm_chunk_work *cw)
*/
static void dmz_put_chunk_work(struct dm_chunk_work *cw)
{
if (atomic_dec_and_test(&cw->refcount)) {
if (refcount_dec_and_test(&cw->refcount)) {
WARN_ON(!bio_list_empty(&cw->bio_list));
radix_tree_delete(&cw->target->chunk_rxtree, cw->chunk);
kfree(cw);
@ -546,7 +546,7 @@ static void dmz_queue_chunk_work(struct dmz_target *dmz, struct bio *bio)
goto out;
INIT_WORK(&cw->work, dmz_chunk_work);
atomic_set(&cw->refcount, 0);
refcount_set(&cw->refcount, 0);
cw->target = dmz;
cw->chunk = chunk;
bio_list_init(&cw->bio_list);
@ -599,7 +599,7 @@ static int dmz_map(struct dm_target *ti, struct bio *bio)
bioctx->target = dmz;
bioctx->zone = NULL;
bioctx->bio = bio;
atomic_set(&bioctx->ref, 1);
refcount_set(&bioctx->ref, 1);
bioctx->status = BLK_STS_OK;
/* Set the BIO pending in the flush list */
@ -633,7 +633,7 @@ static int dmz_end_io(struct dm_target *ti, struct bio *bio, blk_status_t *error
if (bioctx->status == BLK_STS_OK && *error)
bioctx->status = *error;
if (!atomic_dec_and_test(&bioctx->ref))
if (!refcount_dec_and_test(&bioctx->ref))
return DM_ENDIO_INCOMPLETE;
/* Done */