io_uring: deduplicate cancellation code

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>
Link: https://lore.kernel.org/r/900122b588e65b637e71bfec80a260726c6a54d6.1628981736.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d6e0e7e..a23b608 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5792,32 +5792,24 @@ 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,
@@ -5841,17 +5833,7 @@ 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);
@@ -6418,9 +6400,17 @@ 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 {