Commit ea5ab3b5 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

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: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d439efad0503c8398451dae075e68a04362fbc8d.1621201931.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a566c556

fs/io_uring.c

+4 −8
Original line number Diff line number Diff line
@@ -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) {