io_uring: terminate manual loop iterator loop correctly for non-vecs

The fix for not advancing the iterator if we're using fixed buffers is broken in that it can hit a condition where we don't terminate the loop. This results in io-wq looping forever, asking to read (or write) 0 bytes for every subsequent loop.

Jens Axboe committed 4 years ago

Commit 5e929361 parent adf3a9e1 file · +4 −2Browse files

Unified · Split

fs/io_uring.c+4−2

@@ -3612,13 +3612,15 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb req, struct iov_iter iter) · 3611 unmodified lines
3612	3612	ret = nr;
3613	3613	break;
3614	3614	}
	3615	+ ret += nr;
3615	3616	if (!iov_iter_is_bvec(iter)) {
3616	3617	iov_iter_advance(iter, nr);
3617	3618	} else {
3618		− req->rw.len -= nr;
3619	3619	req->rw.addr += nr;
	3620	+ req->rw.len -= nr;
	3621	+ if (!req->rw.len)
	3622	+ break;
3620	3623	}
3621		− ret += nr;
3622	3624	if (nr != iovec.iov_len)
3623	3625	break;
3624	3626	}