From fa780334a8c392d959ae05eb19f2410b3a1e6cb0 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 9 Mar 2023 09:51:13 -0700 Subject: [PATCH] =?UTF-8?q?io=5Furing:=20silence=20variable=20=E2=80=98pre?= =?UTF-8?q?v=E2=80=99=20set=20but=20not=20used=20warning?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If io_uring.o is built with W=1, it triggers a warning: io_uring/io_uring.c: In function ‘__io_submit_flush_completions’: io_uring/io_uring.c:1502:40: warning: variable ‘prev’ set but not used [-Wunused-but-set-variable] 1502 | struct io_wq_work_node *node, *prev; | ^~~~ which is due to the wq_list_for_each() iterator always keeping a 'prev' variable. Most users need this to remove an entry from a list, for example, but __io_submit_flush_completions() never does that. Add a basic helper that doesn't track prev instead, and use that in that function. Reported-by: Vincenzo Palazzo Reviewed-by: Vincenzo Palazzo Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 4 ++-- io_uring/slist.h | 5 ++++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index fd1cc35a1c00..722624b6d0dc 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1499,14 +1499,14 @@ void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node) 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_submit_state *state = &ctx->submit_state; + struct io_wq_work_node *node; __io_cq_lock(ctx); /* must come first to preserve CQE ordering in failure cases */ if (state->cqes_count) __io_flush_post_cqes(ctx); - wq_list_for_each(node, prev, &state->compl_reqs) { + __wq_list_for_each(node, &state->compl_reqs) { struct io_kiocb *req = container_of(node, struct io_kiocb, comp_list); diff --git a/io_uring/slist.h b/io_uring/slist.h index 7c198a40d5f1..0eb194817242 100644 --- a/io_uring/slist.h +++ b/io_uring/slist.h @@ -3,6 +3,9 @@ #include +#define __wq_list_for_each(pos, head) \ + for (pos = (head)->first; pos; pos = (pos)->next) + #define wq_list_for_each(pos, prv, head) \ for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next) @@ -113,4 +116,4 @@ static inline struct io_wq_work *wq_next_work(struct io_wq_work *work) return container_of(work->list.next, struct io_wq_work, list); } -#endif // INTERNAL_IO_SLIST_H \ No newline at end of file +#endif // INTERNAL_IO_SLIST_H