[PATCH 5.14 022/432] 9p/xen: Fix end of loop tests for list_for_each_entry

Greg Kroah-Hartman
2021-09-16T17:11:58Z

From: Harshvardhan Jha <harshvardhan.jha@oracle.com>

commit 732b33d0dbf17e9483f0b50385bf606f724f50a2 upstream.

This patch addresses the following problems:
- priv can never be NULL, so this part of the check is useless
- if the loop ran through the whole list, priv->client is invalid and
it is more appropriate and sufficient to check for the end of
list_for_each_entry loop condition.

Link: http://lkml.kernel.org/r/20210727000709.225032-1-harshvardhan.jha@oracle.com
Signed-off-by: Harshvardhan Jha <harshvardhan.jha@oracle.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/9p/trans_xen.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -138,7 +138,7 @@ static bool p9_xen_write_todo(struct xen

static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
{
- struct xen_9pfs_front_priv *priv = NULL;
+ struct xen_9pfs_front_priv *priv;
RING_IDX cons, prod, masked_cons, masked_prod;
unsigned long flags;
u32 size = p9_req->tc.size;
@@ -151,7 +151,7 @@ static int p9_xen_request(struct p9_clie
break;
}
read_unlock(&xen_9pfs_lock);
- if (!priv || priv->client != client)
+ if (list_entry_is_head(priv, &xen_9pfs_devs, list))
return -EINVAL;

num = p9_req->tc.tag % priv->num_rings;