io_uring: unconditionally grab req->task

commit e3bc8e9dad7f2f83cc807111d4472164c9210153 upstream.

Sometimes we assign a weak reference to it, sometimes we grab a
reference to it. Clean this up and make it unconditional, and drop the
flag related to tracking this state.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 171ea70d5350d56a27e556319119ae6cd15e1efc..908b26abcc9c94d88181224510a260711ae7a76e 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -550,7 +550,6 @@ enum {
        REQ_F_NO_FILE_TABLE_BIT,
        REQ_F_QUEUE_TIMEOUT_BIT,
        REQ_F_WORK_INITIALIZED_BIT,
-       REQ_F_TASK_PINNED_BIT,
 
        /* not a real bit, just to check we're not overflowing the space */
        __REQ_F_LAST_BIT,
@@ -608,8 +607,6 @@ enum {
        REQ_F_QUEUE_TIMEOUT     = BIT(REQ_F_QUEUE_TIMEOUT_BIT),
        /* io_wq_work is initialized */
        REQ_F_WORK_INITIALIZED  = BIT(REQ_F_WORK_INITIALIZED_BIT),
-       /* req->task is refcounted */
-       REQ_F_TASK_PINNED       = BIT(REQ_F_TASK_PINNED_BIT),
 };
 
 struct async_poll {
@@ -924,21 +921,6 @@ struct sock *io_uring_get_socket(struct file *file)
 }
 EXPORT_SYMBOL(io_uring_get_socket);
 
-static void io_get_req_task(struct io_kiocb *req)
-{
-       if (req->flags & REQ_F_TASK_PINNED)
-               return;
-       get_task_struct(req->task);
-       req->flags |= REQ_F_TASK_PINNED;
-}
-
-/* not idempotent -- it doesn't clear REQ_F_TASK_PINNED */
-static void __io_put_req_task(struct io_kiocb *req)
-{
-       if (req->flags & REQ_F_TASK_PINNED)
-               put_task_struct(req->task);
-}
-
 static void io_file_put_work(struct work_struct *work);
 
 /*
@@ -1455,7 +1437,7 @@ static void __io_req_aux_free(struct io_kiocb *req)
        kfree(req->io);
        if (req->file)
                io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
-       __io_put_req_task(req);
+       put_task_struct(req->task);
        io_req_work_drop_env(req);
 }
 
@@ -1765,7 +1747,7 @@ static inline bool io_req_multi_free(struct req_batch *rb, struct io_kiocb *req)
        if ((req->flags & REQ_F_LINK_HEAD) || io_is_fallback_req(req))
                return false;
 
-       if (req->file || req->io)
+       if (req->file || req->io || req->task)
                rb->need_iter++;
 
        rb->reqs[rb->to_free++] = req;
@@ -4584,7 +4566,6 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
        if (req->flags & REQ_F_WORK_INITIALIZED)
                memcpy(&apoll->work, &req->work, sizeof(req->work));
 
-       io_get_req_task(req);
        req->apoll = apoll;
        INIT_HLIST_NODE(&req->hash_node);
 
@@ -4774,8 +4755,6 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe
 
        events = READ_ONCE(sqe->poll_events);
        poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
-
-       io_get_req_task(req);
        return 0;
 }
 
@@ -6057,6 +6036,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
        /* one is dropped after submission, the other at completion */
        refcount_set(&req->refs, 2);
        req->task = current;
+       get_task_struct(req->task);
        req->result = 0;
 
        if (unlikely(req->opcode >= IORING_OP_LAST))