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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: John Pittman <jpittman@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
John Pittman 2018-08-27 14:33:05 -04:00 committed by Jens Axboe
parent 62d2a19407
commit db193954ed
1 changed files with 4 additions and 4 deletions
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8
block/bsg.c
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@ -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;
}
}