From: Pavel Begunkov Date: Mon, 14 Jun 2021 22:37:23 +0000 (+0100) Subject: io_uring: refactor io_get_sqe() X-Git-Tag: v5.15~839^2~49 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=17d3aeb33cdae8c87a8ad97c4358a623a630e19a;p=platform%2Fkernel%2Flinux-starfive.git io_uring: refactor io_get_sqe() The line of io_get_sqe() evaluating @head consists of too many operations including READ_ONCE(), it's not convenient for probing. Refactor it also improving readability. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/866ad6e4ef4851c7c61f6b0e08dbd0a8d1abce84.1623709150.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- diff --git a/fs/io_uring.c b/fs/io_uring.c index a0720fb..c74a84a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6685,8 +6685,8 @@ static void io_commit_sqring(struct io_ring_ctx *ctx) */ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) { - u32 *sq_array = ctx->sq_array; unsigned head, mask = ctx->sq_entries - 1; + unsigned sq_idx = ctx->cached_sq_head++ & mask; /* * The cached sq head (or cq tail) serves two purposes: @@ -6696,7 +6696,7 @@ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) * 2) allows the kernel side to track the head on its own, even * though the application is the one updating it. */ - head = READ_ONCE(sq_array[ctx->cached_sq_head++ & mask]); + head = READ_ONCE(ctx->sq_array[sq_idx]); if (likely(head < ctx->sq_entries)) return &ctx->sq_sqes[head];