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

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2006-03-18 14:58:37 -05:00
parent 334e94de9b
commit 6f325a1344
1 changed files with 12 additions and 4 deletions
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16
block/cfq-iosched.c
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@ -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;