Commit ebdeb7c0 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: add support for 128-byte SQEs 



Normal SQEs are 64-bytes in length, which is fine for all the commands
we support. However, in preparation for supporting passthrough IO,
provide an option for setting up a ring with 128-byte SQEs.

We continue to use the same type for io_uring_sqe, it's marked and
commented with a zero sized array pad at the end. This provides up
to 80 bytes of data for a passthrough command - 64 bytes for the
extra added data, and 16 bytes available at the end of the existing
SQE.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b5ba65df

fs/io_uring.c

+11 −3
Original line number Diff line number Diff line
@@ -8519,8 +8519,12 @@ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) 
	 *    though the application is the one updating it.

	 */

	head = READ_ONCE(ctx->sq_array[sq_idx]);

	if (likely(head < ctx->sq_entries))

	if (likely(head < ctx->sq_entries)) {

		/* double index for 128-byte SQEs, twice as long */

		if (ctx->flags & IORING_SETUP_SQE128)

			head <<= 1;

		return &ctx->sq_sqes[head];

	}



	/* drop invalid entries */

	ctx->cq_extra--;
@@ -11689,6 +11693,9 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx, 
	rings->sq_ring_entries = p->sq_entries;

	rings->cq_ring_entries = p->cq_entries;



	if (p->flags & IORING_SETUP_SQE128)

		size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);

	else

		size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);

	if (size == SIZE_MAX) {

		io_mem_free(ctx->rings);
@@ -11933,7 +11940,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) 
			IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |

			IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |

			IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |

			IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG))

			IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |

			IORING_SETUP_SQE128))

		return -EINVAL;



	return io_uring_create(entries, &p, params);

include/uapi/linux/io_uring.h

+8 −0
Original line number Diff line number Diff line
@@ -63,6 +63,12 @@ struct io_uring_sqe { 
	};

	__u64	addr3;

	__u64	__pad2[1];



	/*

	 * If the ring is initialized with IORING_SETUP_SQE128, then this field

	 * contains 64-bytes of padding, doubling the size of the SQE.

	 */

	__u64	__big_sqe_pad[0];

};



enum {
@@ -119,6 +125,8 @@ enum { 
 */

#define IORING_SETUP_TASKRUN_FLAG	(1U << 9)



#define IORING_SETUP_SQE128		(1U << 10) /* SQEs are 128 byte */



enum io_uring_op {

	IORING_OP_NOP,

	IORING_OP_READV,