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| author |   Pavel Begunkov <asml.silence@gmail.com> | 2021-10-19 20:31:26 +0100 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2021-10-19 17:09:34 -0600 |
| commit | bc369921d6708542eb93da33478762f1162a5805 (patch) | |
| tree | f9ce142cfbdd5091d546acfcc872682b330e6d05 /fs/io-wq.c | |
| parent | io_uring: fix wrong condition to grab uring lock (diff) | |
| download | wireguard-linux-bc369921d6708542eb93da33478762f1162a5805.tar.xz wireguard-linux-bc369921d6708542eb93da33478762f1162a5805.zip | |
io-wq: max_worker fixes
First, fix nr_workers checks against max_workers, with max_worker
registration, it may pretty easily happen that nr_workers > max_workers.
Also, synchronise writing to acct->max_worker with wqe->lock. It's not
an actual problem, but as we don't care about io_wqe_create_worker(),
it's better than WRITE_ONCE()/READ_ONCE().
Fixes: 2e480058ddc2 ("io-wq: provide a way to limit max number of workers")
Reported-by: Beld Zhang <beldzhang@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/11f90e6b49410b7d1a88f5d04fb8d95bb86b8cf3.1634671835.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io-wq.c')
| -rw-r--r-- | fs/io-wq.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c index 5bf8aa81715e..422a7ed6a9bd 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -253,7 +253,7 @@ static bool io_wqe_create_worker(struct io_wqe *wqe, struct io_wqe_acct *acct) pr_warn_once("io-wq is not configured for unbound workers"); raw_spin_lock(&wqe->lock); - if (acct->nr_workers == acct->max_workers) { + if (acct->nr_workers >= acct->max_workers) { raw_spin_unlock(&wqe->lock); return true; } @@ -1291,15 +1291,18 @@ int io_wq_max_workers(struct io_wq *wq, int *new_count) rcu_read_lock(); for_each_node(node) { + struct io_wqe *wqe = wq->wqes[node]; struct io_wqe_acct *acct; + raw_spin_lock(&wqe->lock); for (i = 0; i < IO_WQ_ACCT_NR; i++) { - acct = &wq->wqes[node]->acct[i]; + acct = &wqe->acct[i]; prev = max_t(int, acct->max_workers, prev); if (new_count[i]) acct->max_workers = new_count[i]; new_count[i] = prev; } + raw_spin_unlock(&wqe->lock); } rcu_read_unlock(); return 0; |