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Commit 6f325a13 authored by Al Viro's avatar Al Viro
Browse files

[PATCH] fix cfq_get_queue()/ioprio_set(2) races 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 334e94de

block/cfq-iosched.c

+12 −4
Original line number Diff line number Diff line
@@ -296,6 +296,7 @@ CFQ_CRQ_FNS(is_sync); 
static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);

static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *);

static void cfq_put_cfqd(struct cfq_data *cfqd);

static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);



#define process_sync(tsk)	((tsk)->flags & PF_SYNCWRITE)
@@ -1365,8 +1366,13 @@ static inline void changed_ioprio(struct cfq_io_context *cic) 
		spin_lock(cfqd->queue->queue_lock);

		cfqq = cic->cfqq[ASYNC];

		if (cfqq) {

			cfq_mark_cfqq_prio_changed(cfqq);

			cfq_init_prio_data(cfqq);

			struct cfq_queue *new_cfqq;

			new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC,

						cic->ioc->task, GFP_ATOMIC);

			if (new_cfqq) {

				cic->cfqq[ASYNC] = new_cfqq;

				cfq_put_queue(cfqq);

			}

		}

		cfqq = cic->cfqq[SYNC];

		if (cfqq) {
@@ -1399,13 +1405,15 @@ static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) 
}



static struct cfq_queue *

cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio,

cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,

	      gfp_t gfp_mask)

{

	const int hashval = hash_long(key, CFQ_QHASH_SHIFT);

	struct cfq_queue *cfqq, *new_cfqq = NULL;

	unsigned short ioprio;



retry:

	ioprio = tsk->ioprio;

	cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);



	if (!cfqq) {
@@ -1982,7 +1990,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, 
		goto queue_fail;



	if (!cic->cfqq[is_sync]) {

		cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask);

		cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask);

		if (!cfqq)

			goto queue_fail;