From df6d3422d3eed27afa23df092b3ce147c558d1a8 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 6 Sep 2022 17:11:16 +0100
Subject: [PATCH] io_uring/kbuf: fix not advancing READV kbuf ring
Git-commit: df6d3422d3eed27afa23df092b3ce147c558d1a8
Patch-mainline: v6.0-rc5
References: git-fixes

When we don't recycle a selected ring buffer we should advance the head
of the ring, so don't just skip io_kbuf_recycle() for IORING_OP_READV
but adjust the ring.

Fixes: 934447a603b22 ("io_uring: do not recycle buffer in READV")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/a6d85e2611471bcb5d5dcd63a8342077ddc2d73d.1662480490.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel krisman Bertazi <krisman@suse.de>
---
 fs/io_uring.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1670,8 +1670,13 @@ static void io_kbuf_recycle(struct io_ki
 	 * buffer data. However if that buffer is recycled the original request
 	 * data stored in addr is lost. Therefore forbid recycling for now.
 	 */
-	if (req->opcode == IORING_OP_READV)
+	if (req->opcode == IORING_OP_READV) {
+		if ((req->flags & REQ_F_BUFFER_RING) && req->buf_list) {
+			req->buf_list->head++;
+			req->buf_list = NULL;
+		}
 		return;
+	}
 
 	/*
 	 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear