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Commit db193954 authored by John Pittman's avatar John Pittman Committed by Jens Axboe
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block: bsg: move atomic_t ref_count variable to refcount API 



Currently, variable ref_count within the bsg_device struct is of
type atomic_t.  For variables being used as reference counters,
the refcount API should be used instead of atomic.  The newer
refcount API works to prevent counter overflows and use-after-free
bugs.  So, move this varable from the atomic API to refcount,
potentially avoiding the issues mentioned.

Signed-off-by: default avatarJohn Pittman <jpittman@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 62d2a194

block/bsg.c

+4 −4
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ struct bsg_device { 
	struct request_queue *queue;

	spinlock_t lock;

	struct hlist_node dev_list;

	atomic_t ref_count;

	refcount_t ref_count;

	char name[20];

	int max_queue;

};
@@ -252,7 +252,7 @@ static int bsg_put_device(struct bsg_device *bd) 


	mutex_lock(&bsg_mutex);



	if (!atomic_dec_and_test(&bd->ref_count)) {

	if (!refcount_dec_and_test(&bd->ref_count)) {

		mutex_unlock(&bsg_mutex);

		return 0;

	}
@@ -290,7 +290,7 @@ static struct bsg_device *bsg_add_device(struct inode *inode, 


	bd->queue = rq;



	atomic_set(&bd->ref_count, 1);

	refcount_set(&bd->ref_count, 1);

	hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));



	strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
@@ -308,7 +308,7 @@ static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 


	hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {

		if (bd->queue == q) {

			atomic_inc(&bd->ref_count);

			refcount_inc(&bd->ref_count);

			goto found;

		}

	}