[PATCH v3 2/2] 9p/trans_xen: replace simple_strto* with kstrtouint

Eric-Terminal
2026-03-24T15:30:36Z

In xen_9pfs_front_init(), parse the backend version list as comma-separated
tokens with kstrtouint(), keep strict token validation, and explicitly
require protocol version 1 to be present.

This replaces the deprecated simple_strtoul(), improves error reporting
consistency, and avoids partially parsed values in control paths.

Signed-off-by: Yufan Chen <ericterminal@gmail.com>
---
v3:
- Split from mixed series into a dedicated 9p/trans_xen series.
- Refined commit message to focus on 9p changes.
- No functional changes since v2.

net/9p/trans_xen.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index 85b9ebfaa..f9fb2db7a 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -413,23 +413,29 @@ static int xen_9pfs_front_init(struct xenbus_device *dev)
int ret, i;
struct xenbus_transaction xbt;
struct xen_9pfs_front_priv *priv;
- char *versions, *v;
- unsigned int max_rings, max_ring_order, len = 0;
+ char *versions, *v, *token;
+ bool version_1 = false;
+ unsigned int max_rings, max_ring_order, len = 0, version;

versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
if (IS_ERR(versions))
return PTR_ERR(versions);
- for (v = versions; *v; v++) {
- if (simple_strtoul(v, &v, 10) == 1) {
- v = NULL;
- break;
+ for (v = versions; (token = strsep(&v, ",")); ) {
+ if (!*token)
+ continue;
+
+ ret = kstrtouint(token, 10, &version);
+ if (ret) {
+ kfree(versions);
+ return ret;
}
- }
- if (v) {
- kfree(versions);
- return -EINVAL;
+ if (version == 1)
+ version_1 = true;
}
kfree(versions);
+ if (!version_1)
+ return -EINVAL;
+
max_rings = xenbus_read_unsigned(dev->otherend, "max-rings", 0);
if (max_rings < XEN_9PFS_NUM_RINGS)