Fix build errors on Linux 5.10

https://github.com/aircrack-ng/rtl8812au/pull/773/files

os_dep/osdep_service.c

@@ -2213,18 +2213,18 @@ static int isFileReadable(const char *path, u32 *sz)
 {
 	struct file *fp;
 	int ret = 0;
+    #ifdef set_fs
 	mm_segment_t oldfs;
+    #endif
 	char buf;
 
 	fp = filp_open(path, O_RDONLY, 0);
 	if (IS_ERR(fp))
 		ret = PTR_ERR(fp);
 	else {
+        #ifdef set_fs
 		oldfs = get_fs();
-		#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0))
 		set_fs(KERNEL_DS);
-		#else
-		set_fs(get_ds());
 		#endif
 
 		if (1 != readFile(fp, &buf, 1))
@@ -2238,7 +2238,9 @@ static int isFileReadable(const char *path, u32 *sz)
 			#endif
 		}
 
+		#ifdef set_fs
 		set_fs(oldfs);
+        #endif
 		filp_close(fp, NULL);
 	}
 	return ret;
@@ -2254,7 +2256,9 @@ static int isFileReadable(const char *path, u32 *sz)
 static int retriveFromFile(const char *path, u8 *buf, u32 sz)
 {
 	int ret = -1;
+    #ifdef set_fs
 	mm_segment_t oldfs;
+    #endif
 	struct file *fp;
 
 	if (path && buf) {
@@ -2262,14 +2266,14 @@ static int retriveFromFile(const char *path, u8 *buf, u32 sz)
 		if (0 == ret) {
 			RTW_INFO("%s openFile path:%s fp=%p\n", __FUNCTION__, path , fp);
 
+            #ifdef set_fs
 			oldfs = get_fs();
-			#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0))
 			set_fs(KERNEL_DS);
-			#else
-			set_fs(get_ds());
-			#endif
 			ret = readFile(fp, buf, sz);
 			set_fs(oldfs);
+            #else
+            ret = readFile(fp, buf, sz);
+            #endif
 			closeFile(fp);
 
 			RTW_INFO("%s readFile, ret:%d\n", __FUNCTION__, ret);
@@ -2293,7 +2297,9 @@ static int retriveFromFile(const char *path, u8 *buf, u32 sz)
 static int storeToFile(const char *path, u8 *buf, u32 sz)
 {
 	int ret = 0;
+    #ifdef set_fs
 	mm_segment_t oldfs;
+    #endif
 	struct file *fp;
 
 	if (path && buf) {
@@ -2301,14 +2307,14 @@ static int storeToFile(const char *path, u8 *buf, u32 sz)
 		if (0 == ret) {
 			RTW_INFO("%s openFile path:%s fp=%p\n", __FUNCTION__, path , fp);
 
+            #ifdef set_fs
 			oldfs = get_fs();
-			#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0))
 			set_fs(KERNEL_DS);
-			#else
-			set_fs(get_ds());
-			#endif
 			ret = writeFile(fp, buf, sz);
 			set_fs(oldfs);
+            #else
+            ret = writeFile(fp, buf, sz);
+            #endif
 			closeFile(fp);
 
 			RTW_INFO("%s writeFile, ret:%d\n", __FUNCTION__, ret);