fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare()

Clang warns:

  fs/ntfs3/namei.c:445:7: error: variable 'uni1' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
                  if (toupper(c1) != toupper(c2)) {
                      ^~~~~~~~~~~~~~~~~~~~~~~~~~
  ./include/linux/ctype.h:64:20: note: expanded from macro 'toupper'
  #define toupper(c) __toupper(c)
                    ^
  fs/ntfs3/namei.c:487:12: note: uninitialized use occurs here
          __putname(uni1);
                    ^~~~
  ./include/linux/fs.h:2789:65: note: expanded from macro '__putname'
  #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
                                                                        ^~~~
  fs/ntfs3/namei.c:445:3: note: remove the 'if' if its condition is always false
                  if (toupper(c1) != toupper(c2)) {
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  fs/ntfs3/namei.c:434:7: error: variable 'uni1' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
                  if (!lm--) {
                      ^~~~~
  fs/ntfs3/namei.c:487:12: note: uninitialized use occurs here
          __putname(uni1);
                    ^~~~
  ./include/linux/fs.h:2789:65: note: expanded from macro '__putname'
  #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
                                                                        ^~~~
  fs/ntfs3/namei.c:434:3: note: remove the 'if' if its condition is always false
                  if (!lm--) {
                  ^~~~~~~~~~~~
  fs/ntfs3/namei.c:430:22: note: initialize the variable 'uni1' to silence this warning
          struct cpu_str *uni1, *uni2;
                              ^
                              = NULL
  2 errors generated.

There is no point in calling __putname() in these particular error
paths, as there has been no corresponding __getname() call yet. Just
return directly in these blocks to clear up the warning.

Fixes: a3a956c ("fs/ntfs3: Add option "nocase"")
Link: ClangBuiltLinux/linux#1729
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Konstantin Komarov <[email protected]>

Author: nathanchance

fs/ntfs3/namei.c

@@ -431,21 +431,17 @@ static int ntfs_d_compare(const struct dentry *dentry, unsigned int len1,
 
 	/* First try fast implementation. */
 	for (;;) {
-		if (!lm--) {
-			ret = len1 == len2 ? 0 : 1;
-			goto out;
-		}
+		if (!lm--)
+			return len1 == len2 ? 0 : 1;
 
 		if ((c1 = *n1++) == (c2 = *n2++))
 			continue;
 
 		if (c1 >= 0x80 || c2 >= 0x80)
 			break;
 
-		if (toupper(c1) != toupper(c2)) {
-			ret = 1;
-			goto out;
-		}
+		if (toupper(c1) != toupper(c2))
+			return 1;
 	}
 
 	/*