lib/string_helpers: move ESCAPE_NP check inside 'else' branch in a loop

Refactor code to have better readability by moving ESCAPE_NP handling
inside 'else' branch in the loop.

No functional change intended.

Link: https://lkml.kernel.org/r/20210504180819.73127-3-andriy.shevchenko@linux.intel.comSigned-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/string_helpers.c

@@ -452,10 +452,10 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
  * The process of escaping byte buffer includes several parts. They are applied
  * in the following sequence.
  *
- *	1. The character is matched to the printable class, if asked, and in
- *	   case of match it passes through to the output.
- *	2. The character is not matched to the one from @only string and thus
+ *	1. The character is not matched to the one from @only string and thus
  *	   must go as-is to the output.
+ *	2. The character is matched to the printable class, if asked, and in
+ *	   case of match it passes through to the output.
  *	3. The character is checked if it falls into the class given by @flags.
  *	   %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
  *	   character. Note that they actually can't go together, otherwise
@@ -506,19 +506,22 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 
 		/*
 		 * Apply rules in the following sequence:
-		 *	- the character is printable, when @flags has
-		 *	  %ESCAPE_NP bit set
 		 *	- the @only string is supplied and does not contain a
 		 *	  character under question
+		 *	- the character is printable, when @flags has
+		 *	  %ESCAPE_NP bit set
 		 *	- the character doesn't fall into a class of symbols
 		 *	  defined by given @flags
 		 * In these cases we just pass through a character to the
 		 * output buffer.
 		 */
-		if ((flags & ESCAPE_NP && isprint(c)) ||
-		    (is_dict && !strchr(only, c))) {
+		if (is_dict && !strchr(only, c)) {
 			/* do nothing */
 		} else {
+			if (isprint(c) &&
+			    flags & ESCAPE_NP && escape_passthrough(c, &p, end))
+				continue;
+
 			if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
 				continue;