[PATCH 5.10 088/252] usb: typec: mux: Fix matching with typec_altmode_desc

[Greg Kroah-Hartman]

From: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>

commit acf5631c239dfc53489f739c4ad47f490c5181ff upstream.

In typec_mux_match() "nval" is assigned the number of elements in the
"svid" fwnode property, then the variable is used to store the success
of the read and finally attempts to loop between 0 and "success" - i.e.
not at all - and the code returns indicating that no match was found.

Fix this by using a separate variable to track the success of the read,
to allow the loop to get a change to find a match.

Fixes: 96a6d031ca99 ("usb: typec: mux: Find the muxes by also matching against the device node")
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210516034730.621461-1-bjorn.andersson@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/usb/typec/mux.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/usb/typec/mux.c
+++ b/drivers/usb/typec/mux.c
@@ -191,6 +191,7 @@ static void *typec_mux_match(struct fwno
 	bool match;
 	int nval;
 	u16 *val;
+	int ret;
 	int i;
 
 	/*
@@ -218,10 +219,10 @@ static void *typec_mux_match(struct fwno
 	if (!val)
 		return ERR_PTR(-ENOMEM);
 
-	nval = fwnode_property_read_u16_array(fwnode, "svid", val, nval);
-	if (nval < 0) {
+	ret = fwnode_property_read_u16_array(fwnode, "svid", val, nval);
+	if (ret < 0) {
 		kfree(val);
-		return ERR_PTR(nval);
+		return ERR_PTR(ret);
 	}
 
 	for (i = 0; i < nval; i++) {