udf: udf_CS0toUTF8 cleanup

- fix error handling - always zero output variable
- don't zero explicitely fields zeroed by memset
- mark "in" paramater as const
- remove outdated comment

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

2 files changed, 11 insertions, 18 deletions

diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
index d3aae5633722..2310b5c8fd8b 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -175,7 +175,7 @@ extern int udf_get_filename(struct super_block *, uint8_t *, uint8_t *, int);
 extern int udf_put_filename(struct super_block *, const uint8_t *, uint8_t *,
                             int);
 extern int udf_build_ustr(struct ustr *, dstring *, int);
-extern int udf_CS0toUTF8(struct ustr *, struct ustr *);
+extern int udf_CS0toUTF8(struct ustr *, const struct ustr *);
 
 /* ialloc.c */
 extern void udf_free_inode(struct inode *);
diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
index b9de050ad830..05bc505ec01a 100644
--- a/fs/udf/unicode.c
+++ b/fs/udf/unicode.c
@@ -82,9 +82,6 @@ static int udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
  * PURPOSE
  *      Convert OSTA Compressed Unicode to the UTF-8 equivalent.
  *
- * DESCRIPTION
- *      This routine is only called by udf_filldir().
- *
  * PRE-CONDITIONS
  *      utf                     Pointer to UTF-8 output buffer.
  *      ocu                     Pointer to OSTA Compressed Unicode input buffer
@@ -98,43 +95,39 @@ static int udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
  *      November 12, 1997 - Andrew E. Mileski
  *      Written, tested, and released.
  */
-int udf_CS0toUTF8(struct ustr *utf_o, struct ustr *ocu_i)
+int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
 {
-        uint8_t *ocu;
-        uint32_t c;
+        const uint8_t *ocu;
         uint8_t cmp_id, ocu_len;
         int i;
 
-        ocu = ocu_i->u_name;
-
         ocu_len = ocu_i->u_len;
-        cmp_id = ocu_i->u_cmpID;
-        utf_o->u_len = 0;
-
         if (ocu_len == 0) {
                 memset(utf_o, 0, sizeof(struct ustr));
-                utf_o->u_cmpID = 0;
-                utf_o->u_len = 0;
                 return 0;
         }
 
-        if ((cmp_id != 8) && (cmp_id != 16)) {
+        cmp_id = ocu_i->u_cmpID;
+        if (cmp_id != 8 && cmp_id != 16) {
+                memset(utf_o, 0, sizeof(struct ustr));
                 printk(KERN_ERR "udf: unknown compression code (%d) stri=%s\n",
                        cmp_id, ocu_i->u_name);
                 return 0;
         }
 
+        ocu = ocu_i->u_name;
+        utf_o->u_len = 0;
         for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
 
                 /* Expand OSTA compressed Unicode to Unicode */
-                c = ocu[i++];
+                uint32_t c = ocu[i++];
                 if (cmp_id == 16)
                         c = (c << 8) | ocu[i++];
 
                 /* Compress Unicode to UTF-8 */
-                if (c < 0x80U) {
+                if (c < 0x80U)
                         utf_o->u_name[utf_o->u_len++] = (uint8_t)c;
-                } else if (c < 0x800U) {
+                else if (c < 0x800U) {
                         utf_o->u_name[utf_o->u_len++] =
                                                 (uint8_t)(0xc0 | (c >> 6));
                         utf_o->u_name[utf_o->u_len++] =