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

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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
parent c8103c2718 d3e3c102d1
commit 2b7196a219
1 changed files with 15 additions and 2 deletions
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17
fs/io-wq.c
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@ -423,9 +423,10 @@ static inline unsigned int io_get_work_hash(struct io_wq_work *work)
return work->flags >> IO_WQ_HASH_SHIFT; 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; struct io_wq *wq = wqe->wq;
bool ret = false;
spin_lock_irq(&wq->hash->wait.lock); spin_lock_irq(&wq->hash->wait.lock);
if (list_empty(&wqe->wait.entry)) { 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)) { if (!test_bit(hash, &wq->hash->map)) {
__set_current_state(TASK_RUNNING); __set_current_state(TASK_RUNNING);
list_del_init(&wqe->wait.entry); list_del_init(&wqe->wait.entry);
ret = true;
} }
} }
spin_unlock_irq(&wq->hash->wait.lock); spin_unlock_irq(&wq->hash->wait.lock);
return ret;
} }
static struct io_wq_work *io_get_next_work(struct io_wqe_acct *acct, 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) { if (stall_hash != -1U) {
bool unstalled;
/* /*
* Set this before dropping the lock to avoid racing with new * Set this before dropping the lock to avoid racing with new
* work being added and clearing the stalled bit. * work being added and clearing the stalled bit.
*/ */
set_bit(IO_ACCT_STALLED_BIT, &acct->flags); set_bit(IO_ACCT_STALLED_BIT, &acct->flags);
raw_spin_unlock(&wqe->lock); 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); 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; return NULL;
@ -564,8 +574,11 @@ get_next:
io_wqe_enqueue(wqe, linked); io_wqe_enqueue(wqe, linked);
if (hash != -1U && !next_hashed) { 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(hash, &wq->hash->map);
clear_bit(IO_ACCT_STALLED_BIT, &acct->flags); clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
spin_unlock_irq(&wq->hash->wait.lock);
if (wq_has_sleeper(&wq->hash->wait)) if (wq_has_sleeper(&wq->hash->wait))
wake_up(&wq->hash->wait); wake_up(&wq->hash->wait);
raw_spin_lock(&wqe->lock); raw_spin_lock(&wqe->lock);