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authorPavel Begunkov <asml.silence@gmail.com>2021-10-19 20:31:26 +0100
committerJens Axboe <axboe@kernel.dk>2021-10-19 17:09:34 -0600
commitbc369921d6708542eb93da33478762f1162a5805 (patch)
treef9ce142cfbdd5091d546acfcc872682b330e6d05 /fs
parent14cfbb7a7856f190035f8e53045bdbfa648fae41 (diff)
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')
-rw-r--r--fs/io-wq.c7
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;