1 files changed, 10 insertions, 5 deletions

diff --git a/drivers/of/device.c b/drivers/of/device.c
index c5c06997fdd2..11a17582e568 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -195,10 +195,11 @@ EXPORT_SYMBOL(of_device_get_match_data);
 
 static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len)
 {
-        const char *compat, *start = str;
+        const char *compat;
         char *c;
         struct property *p;
         ssize_t csize;
+        ssize_t tsize;
 
         if ((!dev) || (!dev->of_node))
                 return -ENODEV;
@@ -206,12 +207,16 @@ static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len
         /* Name & Type */
         csize = snprintf(str, len, "of:N%sT%s", dev->of_node->name,
                          dev->of_node->type);
+        tsize = csize;
         len -= csize;
-        str += csize;
+        if (str)
+                str += csize;
 
         of_property_for_each_string(dev->of_node, "compatible", p, compat) {
-                if (strlen(compat) + 2 > len)
-                        break;
+                csize = strlen(compat) + 1;
+                tsize += csize;
+                if (csize > len)
+                        continue;
 
                 csize = snprintf(str, len, "C%s", compat);
                 for (c = str; c; ) {
@@ -223,7 +228,7 @@ static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len
                 str += csize;
         }
 
-        return str - start;
+        return tsize;
 }
 
 int of_device_request_module(struct device *dev)