From 97da4a537924d87e2261773f3ac9365abb191fc9 Mon Sep 17 00:00:00 2001
From: Dylan Yudaken <dylany@fb.com>
Date: Mon, 13 Jun 2022 03:11:55 -0700
Subject: [PATCH] io_uring: fix index calculation
Git-commit: 97da4a537924d87e2261773f3ac9365abb191fc9
Patch-mainline: v5.19-rc3
References: bsc#1205205
When indexing into a provided buffer ring, do not subtract 1 from the
index.
Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220613101157.3687-2-dylany@fb.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/io_uring.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 3aab4182fd89..9cf9aff51b70 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -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;
}
--
2.35.3