[PATCH v2 5/9] io_uring: deduplicate cancellation code

Pavel Begunkov
2021-08-15T09:41:10Z

IORING_OP_ASYNC_CANCEL and IORING_OP_LINK_TIMEOUT have enough of
overlap, so extract a helper for request cancellation and use in both.
Also, removes some amount of ugliness because of success_ret.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 46 ++++++++++++++++++----------------------------
1 file changed, 18 insertions(+), 28 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index fb3b07c0f15a..a0d081dca389 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5790,32 +5790,24 @@ static int io_async_cancel_one(struct io_uring_task *tctx, u64 user_data,
return ret;
}

-static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
- struct io_kiocb *req, __u64 sqe_addr,
- int success_ret)
+static int io_try_cancel_userdata(struct io_kiocb *req, u64 sqe_addr)
+ __acquires(&req->ctx->completion_lock)
{
+ struct io_ring_ctx *ctx = req->ctx;
int ret;

+ WARN_ON_ONCE(req->task != current);
+
ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
spin_lock(&ctx->completion_lock);
if (ret != -ENOENT)
- goto done;
+ return ret;
spin_lock_irq(&ctx->timeout_lock);
ret = io_timeout_cancel(ctx, sqe_addr);
spin_unlock_irq(&ctx->timeout_lock);
if (ret != -ENOENT)
- goto done;
- ret = io_poll_cancel(ctx, sqe_addr, false);
-done:
- if (!ret)
- ret = success_ret;
- io_cqring_fill_event(ctx, req->user_data, ret, 0);
- io_commit_cqring(ctx);
- spin_unlock(&ctx->completion_lock);
- io_cqring_ev_posted(ctx);
-
- if (ret < 0)
- req_set_fail(req);
+ return ret;
+ return io_poll_cancel(ctx, sqe_addr, false);
}

static int io_async_cancel_prep(struct io_kiocb *req,
@@ -5839,17 +5831,7 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
struct io_tctx_node *node;
int ret;

- /* tasks should wait for their io-wq threads, so safe w/o sync */
- ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
- spin_lock(&ctx->completion_lock);
- if (ret != -ENOENT)
- goto done;
- spin_lock_irq(&ctx->timeout_lock);
- ret = io_timeout_cancel(ctx, sqe_addr);
- spin_unlock_irq(&ctx->timeout_lock);
- if (ret != -ENOENT)
- goto done;
- ret = io_poll_cancel(ctx, sqe_addr, false);
+ ret = io_try_cancel_userdata(req, sqe_addr);
if (ret != -ENOENT)
goto done;
spin_unlock(&ctx->completion_lock);
@@ -6416,9 +6398,17 @@ static void io_req_task_link_timeout(struct io_kiocb *req)
{
struct io_kiocb *prev = req->timeout.prev;
struct io_ring_ctx *ctx = req->ctx;
+ int ret;

if (prev) {
- io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME);
+ ret = io_try_cancel_userdata(req, prev->user_data);
+ if (!ret)
+ ret = -ETIME;
+ io_cqring_fill_event(ctx, req->user_data, ret, 0);
+ io_commit_cqring(ctx);
+ spin_unlock(&ctx->completion_lock);
+ io_cqring_ev_posted(ctx);
+
io_put_req(prev);
io_put_req(req);
} else {
--
2.32.0