Commit b3659a65 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: change ->cqe_cached invariant for CQE32 



With IORING_SETUP_CQE32 ->cqe_cached doesn't store a real address but
rather an implicit offset into cqes. Store the real cqe pointer and
increment it accordingly if CQE32.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1ee1838cba16bed96381a006950b36ba640d998c.1655455613.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e8c328c3

io_uring/io_uring.c

+10 −5
Original line number Diff line number Diff line
@@ -701,11 +701,8 @@ struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx) 
{

	struct io_rings *rings = ctx->rings;

	unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);

	unsigned int shift = 0;

	unsigned int free, queued, len;



	if (ctx->flags & IORING_SETUP_CQE32)

		shift = 1;



	/* userspace may cheat modifying the tail, be safe and do min */

	queued = min(__io_cqring_events(ctx), ctx->cq_entries);
@@ -715,11 +712,19 @@ struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx) 
	if (!len)

		return NULL;



	ctx->cached_cq_tail++;

	if (ctx->flags & IORING_SETUP_CQE32) {

		off <<= 1;

		len <<= 1;

	}



	ctx->cqe_cached = &rings->cqes[off];

	ctx->cqe_sentinel = ctx->cqe_cached + len;



	ctx->cached_cq_tail++;

	ctx->cqe_cached++;

	if (ctx->flags & IORING_SETUP_CQE32)

		ctx->cqe_cached++;

	return &rings->cqes[off << shift];

	return &rings->cqes[off];

}



static bool io_fill_cqe_aux(struct io_ring_ctx *ctx,

io_uring/io_uring.h

+2 −6
Original line number Diff line number Diff line
@@ -22,14 +22,10 @@ static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx) 
	if (likely(ctx->cqe_cached < ctx->cqe_sentinel)) {

		struct io_uring_cqe *cqe = ctx->cqe_cached;



		if (ctx->flags & IORING_SETUP_CQE32) {

			unsigned int off = ctx->cqe_cached - ctx->rings->cqes;



			cqe += off;

		}



		ctx->cached_cq_tail++;

		ctx->cqe_cached++;

		if (ctx->flags & IORING_SETUP_CQE32)

			ctx->cqe_cached++;

		return cqe;

	}