This is a note to let you know that I've just added the patch titled io_uring: honour zeroes as io-wq worker limits to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: io_uring-honour-zeroes-as-io-wq-worker-limits.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From bad119b9a00019054f0c9e2045f312ed63ace4f4 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov <asml.silence@xxxxxxxxx> Date: Mon, 8 Nov 2021 15:10:03 +0000 Subject: io_uring: honour zeroes as io-wq worker limits From: Pavel Begunkov <asml.silence@xxxxxxxxx> commit bad119b9a00019054f0c9e2045f312ed63ace4f4 upstream. When we pass in zero as an io-wq worker number limit it shouldn't actually change the limits but return the old value, follow that behaviour with deferred limits setup as well. Cc: stable@xxxxxxxxxx # 5.15 Reported-by: Beld Zhang <beldzhang@xxxxxxxxx> Fixes: e139a1ec92f8d ("io_uring: apply max_workers limit to all future users") Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> Link: https://lore.kernel.org/r/1b222a92f7a78a24b042763805e891a4cdd4b544.1636384034.git.asml.silence@xxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -10684,7 +10684,9 @@ static int io_register_iowq_max_workers( BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits)); - memcpy(ctx->iowq_limits, new_count, sizeof(new_count)); + for (i = 0; i < ARRAY_SIZE(new_count); i++) + if (new_count[i]) + ctx->iowq_limits[i] = new_count[i]; ctx->iowq_limits_set = true; ret = -EINVAL; Patches currently in stable-queue which might be from asml.silence@xxxxxxxxx are queue-5.15/io_uring-honour-zeroes-as-io-wq-worker-limits.patch queue-5.15/io-wq-remove-worker-to-owner-tw-dependency.patch