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io_uring: simplify io_get_sqring

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Make io_get_sqring() care only about sqes themselves, not initialising
the io_kiocb. Also, split it into get + consume, that will be helpful in
the future.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-04-08 08:58:43 +03:00 committed by Jens Axboe
parent 45097daea2
commit 709b302fad
1 changed files with 22 additions and 18 deletions
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40
fs/io_uring.c
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@ -5781,8 +5781,7 @@ 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;
@ -5796,25 +5795,18 @@ 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,
@ -5858,11 +5850,23 @@ 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++;