Commit 4c0b26e2 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: add async data clear/free helpers 



Futex recently had an issue where it mishandled how ->async_data and
REQ_F_ASYNC_DATA is handled. To avoid future issues like that, add a set
of helpers that either clear or clear-and-free the async data assigned
to a struct io_kiocb.

Convert existing manual handling of that to use the helpers. No intended
functional changes in this patch.

Reviewed-by: default avatarCaleb Sander Mateos <csander@purestorage.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c986f758

io_uring/futex.c

+4 −9
Original line number Diff line number Diff line
@@ -43,7 +43,6 @@ void io_futex_cache_free(struct io_ring_ctx *ctx) 


static void __io_futex_complete(struct io_kiocb *req, io_tw_token_t tw)

{

	req->async_data = NULL;

	hlist_del_init(&req->hash_node);

	io_req_task_complete(req, tw);

}
@@ -54,6 +53,7 @@ static void io_futex_complete(struct io_kiocb *req, io_tw_token_t tw) 


	io_tw_lock(ctx, tw);

	io_cache_free(&ctx->futex_cache, req->async_data);

	io_req_async_data_clear(req, 0);

	__io_futex_complete(req, tw);

}
@@ -72,8 +72,7 @@ static void io_futexv_complete(struct io_kiocb *req, io_tw_token_t tw) 
			io_req_set_res(req, res, 0);

	}



	kfree(req->async_data);

	req->flags &= ~REQ_F_ASYNC_DATA;

	io_req_async_data_free(req);

	__io_futex_complete(req, tw);

}
@@ -232,9 +231,7 @@ int io_futexv_wait(struct io_kiocb *req, unsigned int issue_flags) 
		io_ring_submit_unlock(ctx, issue_flags);

		req_set_fail(req);

		io_req_set_res(req, ret, 0);

		kfree(futexv);

		req->async_data = NULL;

		req->flags &= ~REQ_F_ASYNC_DATA;

		io_req_async_data_free(req);

		return IOU_COMPLETE;

	}
@@ -310,9 +307,7 @@ int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags) 
	if (ret < 0)

		req_set_fail(req);

	io_req_set_res(req, ret, 0);

	req->async_data = NULL;

	req->flags &= ~REQ_F_ASYNC_DATA;

	kfree(ifd);

	io_req_async_data_free(req);

	return IOU_COMPLETE;

}

io_uring/io_uring.h

+13 −0
Original line number Diff line number Diff line
@@ -281,6 +281,19 @@ static inline bool req_has_async_data(struct io_kiocb *req) 
	return req->flags & REQ_F_ASYNC_DATA;

}



static inline void io_req_async_data_clear(struct io_kiocb *req,

					   io_req_flags_t extra_flags)

{

	req->flags &= ~(REQ_F_ASYNC_DATA|extra_flags);

	req->async_data = NULL;

}



static inline void io_req_async_data_free(struct io_kiocb *req)

{

	kfree(req->async_data);

	io_req_async_data_clear(req, 0);

}



static inline void io_put_file(struct io_kiocb *req)

{

	if (!(req->flags & REQ_F_FIXED_FILE) && req->file)

io_uring/net.c

+2 −4
Original line number Diff line number Diff line
@@ -178,10 +178,8 @@ static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags) 
	if (hdr->vec.nr > IO_VEC_CACHE_SOFT_CAP)

		io_vec_free(&hdr->vec);



	if (io_alloc_cache_put(&req->ctx->netmsg_cache, hdr)) {

		req->async_data = NULL;

		req->flags &= ~(REQ_F_ASYNC_DATA|REQ_F_NEED_CLEANUP);

	}

	if (io_alloc_cache_put(&req->ctx->netmsg_cache, hdr))

		io_req_async_data_clear(req, REQ_F_NEED_CLEANUP);

}



static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req)

io_uring/rw.c

+2 −4
Original line number Diff line number Diff line
@@ -154,10 +154,8 @@ static void io_rw_recycle(struct io_kiocb *req, unsigned int issue_flags) 
	if (rw->vec.nr > IO_VEC_CACHE_SOFT_CAP)

		io_vec_free(&rw->vec);



	if (io_alloc_cache_put(&req->ctx->rw_cache, rw)) {

		req->async_data = NULL;

		req->flags &= ~REQ_F_ASYNC_DATA;

	}

	if (io_alloc_cache_put(&req->ctx->rw_cache, rw))

		io_req_async_data_clear(req, 0);

}



static void io_req_rw_cleanup(struct io_kiocb *req, unsigned int issue_flags)

io_uring/uring_cmd.c

+1 −2
Original line number Diff line number Diff line
@@ -37,8 +37,7 @@ static void io_req_uring_cleanup(struct io_kiocb *req, unsigned int issue_flags) 


	if (io_alloc_cache_put(&req->ctx->cmd_cache, ac)) {

		ioucmd->sqe = NULL;

		req->async_data = NULL;

		req->flags &= ~(REQ_F_ASYNC_DATA|REQ_F_NEED_CLEANUP);

		io_req_async_data_clear(req, REQ_F_NEED_CLEANUP);

	}

}