From bad119b9a00019054f0c9e2045f312ed63ace4f4 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Mon, 8 Nov 2021 15:10:03 +0000
Subject: [PATCH] io_uring: honour zeroes as io-wq worker limits
Git-commit: bad119b9a00019054f0c9e2045f312ed63ace4f4
Patch-mainline: v5.16-rc1
References: bsc#1205205
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@kernel.org # 5.15
Reported-by: Beld Zhang <beldzhang@gmail.com>
Fixes: e139a1ec92f8d ("io_uring: apply max_workers limit to all future users")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1b222a92f7a78a24b042763805e891a4cdd4b544.1636384034.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/io_uring.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index ac1bc8ac4666..b07196b4511c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10791,7 +10791,9 @@ static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx,
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;
if (tctx && tctx->io_wq) {
--
2.35.3