[bug report] io_uring/poll: get rid of unlocked cancel hash

[Dan Carpenter <dan.carpenter@linaro.org>]

Hello Jens Axboe,

Commit 313314db5bcb ("io_uring/poll: get rid of unlocked cancel
hash") from Sep 30, 2024 (linux-next), leads to the following Smatch
static checker warning:

	io_uring/poll.c:932 io_poll_remove()
	warn: duplicate check 'ret2' (previous on line 930)

io_uring/poll.c
    919 int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
    920 {
    921         struct io_poll_update *poll_update = io_kiocb_to_cmd(req, struct io_poll_update);
    922         struct io_ring_ctx *ctx = req->ctx;
    923         struct io_cancel_data cd = { .ctx = ctx, .data = poll_update->old_user_data, };
    924         struct io_kiocb *preq;
    925         int ret2, ret = 0;
    926 
    927         io_ring_submit_lock(ctx, issue_flags);
    928         preq = io_poll_find(ctx, true, &cd);
    929         ret2 = io_poll_disarm(preq);
    930         if (!ret2)
    931                 goto found;
--> 932         if (ret2) {
    933                 ret = ret2;
    934                 goto out;
    935         }

A lot of the function is dead code now.  ;)

    936 found:
    937         if (WARN_ON_ONCE(preq->opcode != IORING_OP_POLL_ADD)) {
    938                 ret = -EFAULT;
    939                 goto out;
    940         }
    941 
    942         if (poll_update->update_events || poll_update->update_user_data) {
    943                 /* only mask one event flags, keep behavior flags */
    944                 if (poll_update->update_events) {
    945                         struct io_poll *poll = io_kiocb_to_cmd(preq, struct io_poll);
    946 
    947                         poll->events &= ~0xffff;
    948                         poll->events |= poll_update->events & 0xffff;
    949                         poll->events |= IO_POLL_UNMASK;
    950                 }
    951                 if (poll_update->update_user_data)
    952                         preq->cqe.user_data = poll_update->new_user_data;
    953 
    954                 ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED);
    955                 /* successfully updated, don't complete poll request */
    956                 if (!ret2 || ret2 == -EIOCBQUEUED)
    957                         goto out;
    958         }
    959 
    960         req_set_fail(preq);
    961         io_req_set_res(preq, -ECANCELED, 0);
    962         preq->io_task_work.func = io_req_task_complete;
    963         io_req_task_work_add(preq);
    964 out:
    965         io_ring_submit_unlock(ctx, issue_flags);
    966         if (ret < 0) {
    967                 req_set_fail(req);
    968                 return ret;
    969         }
    970         /* complete update request, we're done with it */
    971         io_req_set_res(req, ret, 0);
    972         return IOU_OK;
    973 }

regards,
dan carpenter