io_uring: simplify io_prep_linked_timeout

The link test in io_prep_linked_timeout() is pretty bulky, replace it
with a flag. It's better for normal path and linked requests, and also
will be used further for request failing.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3703770bfae8bc1ff370e43ef5767940202cab42.1628981736.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 abf8bb7..097ba59 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -710,6 +710,7 @@ enum {
        REQ_F_DONT_REISSUE_BIT,
        REQ_F_CREDS_BIT,
        REQ_F_REFCOUNT_BIT,
+       REQ_F_ARM_LTIMEOUT_BIT,
        /* keep async read/write and isreg together and in order */
        REQ_F_NOWAIT_READ_BIT,
        REQ_F_NOWAIT_WRITE_BIT,
@@ -765,6 +766,8 @@ enum {
        REQ_F_CREDS             = BIT(REQ_F_CREDS_BIT),
        /* skip refcounting if not set */
        REQ_F_REFCOUNT          = BIT(REQ_F_REFCOUNT_BIT),
+       /* there is a linked timeout that has to be armed */
+       REQ_F_ARM_LTIMEOUT      = BIT(REQ_F_ARM_LTIMEOUT_BIT),
 };
 
 struct async_poll {
@@ -1302,23 +1305,18 @@ static void io_req_track_inflight(struct io_kiocb *req)
 
 static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
 {
-       struct io_kiocb *nxt = req->link;
-
-       if (req->flags & REQ_F_LINK_TIMEOUT)
-               return NULL;
+       req->flags &= ~REQ_F_ARM_LTIMEOUT;
+       req->flags |= REQ_F_LINK_TIMEOUT;
 
        /* linked timeouts should have two refs once prep'ed */
        io_req_set_refcount(req);
-       __io_req_set_refcount(nxt, 2);
-
-       nxt->timeout.head = req;
-       req->flags |= REQ_F_LINK_TIMEOUT;
-       return nxt;
+       __io_req_set_refcount(req->link, 2);
+       return req->link;
 }
 
 static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
 {
-       if (likely(!req->link || req->link->opcode != IORING_OP_LINK_TIMEOUT))
+       if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
                return NULL;
        return __io_prep_linked_timeout(req);
 }
@@ -5700,6 +5698,8 @@ static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        return -EINVAL;
                if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
                        return -EINVAL;
+               req->timeout.head = link->last;
+               link->last->flags |= REQ_F_ARM_LTIMEOUT;
        }
        return 0;
 }