media: pvrusb2: Replaced simple_strtol() with kstrtoint()

It looks like that memcpy() is a superfluous operation in
parse_token()/parse_mtoken(). Simple these two functions and
use kstrtoint() instead of simple_strtol() to avoid data
overflow.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/usb/pvrusb2/pvrusb2-ctrl.c

@@ -355,11 +355,8 @@ static int parse_token(const char *ptr,unsigned int len,
 		       int *valptr,
 		       const char * const *names, unsigned int namecnt)
 {
-	char buf[33];
 	unsigned int slen;
 	unsigned int idx;
-	int negfl;
-	char *p2;
 	*valptr = 0;
 	if (!names) namecnt = 0;
 	for (idx = 0; idx < namecnt; idx++) {
@@ -370,18 +367,7 @@ static int parse_token(const char *ptr,unsigned int len,
 		*valptr = idx;
 		return 0;
 	}
-	negfl = 0;
-	if ((*ptr == '-') || (*ptr == '+')) {
-		negfl = (*ptr == '-');
-		ptr++; len--;
-	}
-	if (len >= sizeof(buf)) return -EINVAL;
-	memcpy(buf,ptr,len);
-	buf[len] = 0;
-	*valptr = simple_strtol(buf,&p2,0);
-	if (negfl) *valptr = -(*valptr);
-	if (*p2) return -EINVAL;
-	return 1;
+	return kstrtoint(ptr, 0, valptr) ? -EINVAL : 1;
 }
 
 
@@ -389,10 +375,8 @@ static int parse_mtoken(const char *ptr,unsigned int len,
 			int *valptr,
 			const char **names,int valid_bits)
 {
-	char buf[33];
 	unsigned int slen;
 	unsigned int idx;
-	char *p2;
 	int msk;
 	*valptr = 0;
 	for (idx = 0, msk = 1; valid_bits; idx++, msk <<= 1) {
@@ -405,12 +389,7 @@ static int parse_mtoken(const char *ptr,unsigned int len,
 		*valptr = msk;
 		return 0;
 	}
-	if (len >= sizeof(buf)) return -EINVAL;
-	memcpy(buf,ptr,len);
-	buf[len] = 0;
-	*valptr = simple_strtol(buf,&p2,0);
-	if (*p2) return -EINVAL;
-	return 0;
+	return kstrtoint(ptr, 0, valptr);
 }