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

[Jens Axboe <axboe@kernel.dk>]

On 10/4/24 7:50 AM, Jens Axboe wrote:
> On 10/4/24 3:00 AM, Dan Carpenter wrote:
>> 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.  ;)
> 
> Thanks, will revisit and fold in a fix!

Should just need this incremental. There's no dead code as far as I can
see, just a needless found label and jump.

diff --git a/io_uring/poll.c b/io_uring/poll.c
index 69382da48c00..217d667e0622 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -940,13 +940,10 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
 	ret2 = io_poll_disarm(preq);
 	if (bucket)
 		spin_unlock(&bucket->lock);
-	if (!ret2)
-		goto found;
 	if (ret2) {
 		ret = ret2;
 		goto out;
 	}
-found:
 	if (WARN_ON_ONCE(preq->opcode != IORING_OP_POLL_ADD)) {
 		ret = -EFAULT;
 		goto out;

-- 
Jens Axboe