io_uring-5.16-2021-11-13

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Merge tag 'io_uring-5.16-2021-11-13' of git://git.kernel.dk/linux-block

Pull io_uring fix from Jens Axboe:
 "Just a single fix here for a buffered write hash stall, which is also
  affecting stable"

* tag 'io_uring-5.16-2021-11-13' of git://git.kernel.dk/linux-block:
  io-wq: serialize hash clear with wakeup
This commit is contained in:
Linus Torvalds 2021-11-13 12:42:50 -08:00
commit 2b7196a219

View file

@ -423,9 +423,10 @@ static inline unsigned int io_get_work_hash(struct io_wq_work *work)
return work->flags >> IO_WQ_HASH_SHIFT;
}
static void io_wait_on_hash(struct io_wqe *wqe, unsigned int hash)
static bool io_wait_on_hash(struct io_wqe *wqe, unsigned int hash)
{
struct io_wq *wq = wqe->wq;
bool ret = false;
spin_lock_irq(&wq->hash->wait.lock);
if (list_empty(&wqe->wait.entry)) {
@ -433,9 +434,11 @@ static void io_wait_on_hash(struct io_wqe *wqe, unsigned int hash)
if (!test_bit(hash, &wq->hash->map)) {
__set_current_state(TASK_RUNNING);
list_del_init(&wqe->wait.entry);
ret = true;
}
}
spin_unlock_irq(&wq->hash->wait.lock);
return ret;
}
static struct io_wq_work *io_get_next_work(struct io_wqe_acct *acct,
@ -475,14 +478,21 @@ static struct io_wq_work *io_get_next_work(struct io_wqe_acct *acct,
}
if (stall_hash != -1U) {
bool unstalled;
/*
* Set this before dropping the lock to avoid racing with new
* work being added and clearing the stalled bit.
*/
set_bit(IO_ACCT_STALLED_BIT, &acct->flags);
raw_spin_unlock(&wqe->lock);
io_wait_on_hash(wqe, stall_hash);
unstalled = io_wait_on_hash(wqe, stall_hash);
raw_spin_lock(&wqe->lock);
if (unstalled) {
clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
if (wq_has_sleeper(&wqe->wq->hash->wait))
wake_up(&wqe->wq->hash->wait);
}
}
return NULL;
@ -564,8 +574,11 @@ static void io_worker_handle_work(struct io_worker *worker)
io_wqe_enqueue(wqe, linked);
if (hash != -1U && !next_hashed) {
/* serialize hash clear with wake_up() */
spin_lock_irq(&wq->hash->wait.lock);
clear_bit(hash, &wq->hash->map);
clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
spin_unlock_irq(&wq->hash->wait.lock);
if (wq_has_sleeper(&wq->hash->wait))
wake_up(&wq->hash->wait);
raw_spin_lock(&wqe->lock);