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Subject[PATCH 1/4] io_uring: simplify io_get_sqring
Date
Make io_get_sqring() to care only about sqes but not initialising
io_kiocb. Also, split it into get + consume, that will be helpful in the
future.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 40 ++++++++++++++++++++++------------------
1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 773f55c49cd8..fa6b7bb62616 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5778,8 +5778,7 @@ static void io_commit_sqring(struct io_ring_ctx *ctx)
* used, it's important that those reads are done through READ_ONCE() to
* prevent a re-load down the line.
*/
-static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req,
- const struct io_uring_sqe **sqe_ptr)
+static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
{
u32 *sq_array = ctx->sq_array;
unsigned head;
@@ -5793,25 +5792,18 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req,
* though the application is the one updating it.
*/
head = READ_ONCE(sq_array[ctx->cached_sq_head & ctx->sq_mask]);
- if (likely(head < ctx->sq_entries)) {
- /*
- * All io need record the previous position, if LINK vs DARIN,
- * it can be used to mark the position of the first IO in the
- * link list.
- */
- req->sequence = ctx->cached_sq_head;
- *sqe_ptr = &ctx->sq_sqes[head];
- req->opcode = READ_ONCE((*sqe_ptr)->opcode);
- req->user_data = READ_ONCE((*sqe_ptr)->user_data);
- ctx->cached_sq_head++;
- return true;
- }
+ if (likely(head < ctx->sq_entries))
+ return &ctx->sq_sqes[head];

/* drop invalid entries */
- ctx->cached_sq_head++;
ctx->cached_sq_dropped++;
WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped);
- return false;
+ return NULL;
+}
+
+static inline void io_consume_sqe(struct io_ring_ctx *ctx)
+{
+ ctx->cached_sq_head++;
}

static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
@@ -5855,11 +5847,23 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
submitted = -EAGAIN;
break;
}
- if (!io_get_sqring(ctx, req, &sqe)) {
+ sqe = io_get_sqe(ctx);
+ if (!sqe) {
__io_req_do_free(req);
+ io_consume_sqe(ctx);
break;
}

+ /*
+ * All io need record the previous position, if LINK vs DARIN,
+ * it can be used to mark the position of the first IO in the
+ * link list.
+ */
+ req->sequence = ctx->cached_sq_head;
+ req->opcode = READ_ONCE(sqe->opcode);
+ req->user_data = READ_ONCE(sqe->user_data);
+ io_consume_sqe(ctx);
+
/* will complete beyond this point, count as submitted */
submitted++;

--
2.24.0
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