USB: replace hardcode maximum usb string length by definition

Replace hardcoded maximum USB string length (126 bytes) by definition
"USB_MAX_STRING_LEN".

Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/1592471618-29428-1-git-send-email-macpaul.lin@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 5c1eb96..8fbf734 100644 (file)
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1085,7 +1085,7 @@ static void collect_langs(struct usb_gadget_strings **sp, __le16 *buf)
        while (*sp) {
                s = *sp;
                language = cpu_to_le16(s->language);
-               for (tmp = buf; *tmp && tmp < &buf[126]; tmp++) {
+               for (tmp = buf; *tmp && tmp < &buf[USB_MAX_STRING_LEN]; tmp++) {
                        if (*tmp == language)
                                goto repeat;
                }
@@ -1160,7 +1160,7 @@ static int get_string(struct usb_composite_dev *cdev,
                        collect_langs(sp, s->wData);
                }
 
-               for (len = 0; len <= 126 && s->wData[len]; len++)
+               for (len = 0; len <= USB_MAX_STRING_LEN && s->wData[len]; len++)
                        continue;
                if (!len)
                        return -EINVAL;

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 9dc06a4..56051bb 100644 (file)
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -103,7 +103,7 @@ static int usb_string_copy(const char *s, char **s_copy)
        char *str;
        char *copy = *s_copy;
        ret = strlen(s);
-       if (ret > 126)
+       if (ret > USB_MAX_STRING_LEN)
                return -EOVERFLOW;
 
        str = kstrdup(s, GFP_KERNEL);

diff --git a/drivers/usb/gadget/usbstring.c b/drivers/usb/gadget/usbstring.c
index 58a4d33..30f889a 100644 (file)
--- a/drivers/usb/gadget/usbstring.c
+++ b/drivers/usb/gadget/usbstring.c
@@ -55,9 +55,9 @@ usb_gadget_get_string (const struct usb_gadget_strings *table, int id, u8 *buf)
                return -EINVAL;
 
        /* string descriptors have length, tag, then UTF16-LE text */
-       len = min ((size_t) 126, strlen (s->s));
+       len = min((size_t)USB_MAX_STRING_LEN, strlen(s->s));
        len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,
-                       (wchar_t *) &buf[2], 126);
+                       (wchar_t *) &buf[2], USB_MAX_STRING_LEN);
        if (len < 0)
                return -EINVAL;
        buf [0] = (len + 1) * 2;

diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
index 456ab0c..b1ed2cc 100644 (file)
--- a/include/uapi/linux/usb/ch9.h
+++ b/include/uapi/linux/usb/ch9.h
@@ -368,6 +368,9 @@ struct usb_config_descriptor {
 
 /*-------------------------------------------------------------------------*/
 
+/* USB String descriptors can contain at most 126 characters. */
+#define USB_MAX_STRING_LEN     126
+
 /* USB_DT_STRING: String descriptor */
 struct usb_string_descriptor {
        __u8  bLength;