Commit 97da4a53 authored by Dylan Yudaken's avatar Dylan Yudaken Committed by Jens Axboe
Browse files

io_uring: fix index calculation 



When indexing into a provided buffer ring, do not subtract 1 from the
index.

Fixes: c7fb1942 ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: default avatarDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220613101157.3687-2-dylany@fb.com


Reviewed-by: default avatarHao Xu <howeyxu@tencent.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b13baccc

fs/io_uring.c

+1 −1
Original line number Diff line number Diff line
@@ -3888,7 +3888,7 @@ static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len, 
		buf = &br->bufs[head];

	} else {

		int off = head & (IO_BUFFER_LIST_BUF_PER_PAGE - 1);

		int index = head / IO_BUFFER_LIST_BUF_PER_PAGE - 1;

		int index = head / IO_BUFFER_LIST_BUF_PER_PAGE;

		buf = page_address(bl->buf_pages[index]);

		buf += off;

	}