From ea5ab3b579836d784357ae9cb5bf9d7242a645b9 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sun, 16 May 2021 22:58:09 +0100 Subject: [PATCH] io_uring: deduce cq_mask from cq_entries No need to cache cq_mask, it's exactly cq_entries - 1, so just deduce it to not carry it around. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/d439efad0503c8398451dae075e68a04362fbc8d.1621201931.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 169e951..a35a8dc 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -362,7 +362,6 @@ struct io_ring_ctx { u32 *sq_array; unsigned cached_sq_head; unsigned sq_entries; - unsigned sq_mask; unsigned sq_thread_idle; unsigned cached_sq_dropped; unsigned cached_cq_overflow; @@ -408,7 +407,6 @@ struct io_ring_ctx { struct { unsigned cached_cq_tail; unsigned cq_entries; - unsigned cq_mask; atomic_t cq_timeouts; unsigned cq_last_tm_flush; unsigned cq_extra; @@ -1367,7 +1365,7 @@ static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx) static inline struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; - unsigned tail; + unsigned tail, mask = ctx->cq_entries - 1; /* * writes to the cq entry need to come after reading head; the @@ -1378,7 +1376,7 @@ static inline struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) return NULL; tail = ctx->cached_cq_tail++; - return &rings->cqes[tail & ctx->cq_mask]; + return &rings->cqes[tail & mask]; } static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx) @@ -6680,7 +6678,7 @@ 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; + unsigned head, mask = ctx->sq_entries - 1; /* * The cached sq head (or cq tail) serves two purposes: @@ -6690,7 +6688,7 @@ 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++ & ctx->sq_mask]); + head = READ_ONCE(sq_array[ctx->cached_sq_head++ & mask]); if (likely(head < ctx->sq_entries)) return &ctx->sq_sqes[head]; @@ -9512,8 +9510,6 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx, rings->cq_ring_mask = p->cq_entries - 1; rings->sq_ring_entries = p->sq_entries; rings->cq_ring_entries = p->cq_entries; - ctx->sq_mask = rings->sq_ring_mask; - ctx->cq_mask = rings->cq_ring_mask; size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); if (size == SIZE_MAX) { -- 2.7.4