Re: [PATCH] io_uring: fix a GCC warning in wq_list_for_each()

From: Pavel Begunkov
Date: Wed Oct 27 2021 - 06:01:12 EST


On 10/25/21 15:59, Qian Cai wrote:
fs/io_uring.c: In function '__io_submit_flush_completions':
fs/io_uring.c:2367:33: warning: variable 'prev' set but not used
[-Wunused-but-set-variable]
2367 | struct io_wq_work_node *node, *prev;
| ^~~~

Fixed it by open-coded the wq_list_for_each() without an unused previous
node pointer.

That's intentional, the var is optimised out and it's better to
not hand code it (if possible).


Fixes: 6f33b0bc4ea4 ("io_uring: use slist for completion batching")
Signed-off-by: Qian Cai <quic_qiancai@xxxxxxxxxxx>
---
fs/io_uring.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 23641d9e0871..b8968bd43e3f 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2361,11 +2361,11 @@ static void io_free_batch_list(struct io_ring_ctx *ctx,
static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
- struct io_wq_work_node *node, *prev;
+ struct io_wq_work_node *node;
struct io_submit_state *state = &ctx->submit_state;
spin_lock(&ctx->completion_lock);
- wq_list_for_each(node, prev, &state->compl_reqs) {
+ for (node = state->compl_reqs.first; node; node = node->next) {
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);


--
Pavel Begunkov