linux-kernel - [PATCH 06/14] d_path: don't bother with return value of prepend()

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Message-Id: <20210519004901.3829541-6-viro@zeniv.linux.org.uk>
Date:   Wed, 19 May 2021 00:48:53 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Jia He <justin.he@....com>, Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Jonathan Corbet <corbet@....net>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ira Weiny <ira.weiny@...el.com>,
        Eric Biggers <ebiggers@...gle.com>,
        "Ahmed S. Darwish" <a.darwish@...utronix.de>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-s390 <linux-s390@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>
Subject: [PATCH 06/14] d_path: don't bother with return value of prepend()

Only simple_dname() checks it, and there we can simply do those
calls and check for overflow (by looking of negative buflen)
in the end.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/d_path.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/d_path.c b/fs/d_path.c
index 311d43287572..72b8087aaf9c 100644
--- a/fs/d_path.c
+++ b/fs/d_path.c
@@ -8,14 +8,13 @@
 #include <linux/prefetch.h>
 #include "mount.h"
 
-static int prepend(char **buffer, int *buflen, const char *str, int namelen)
+static void prepend(char **buffer, int *buflen, const char *str, int namelen)
 {
 	*buflen -= namelen;
-	if (*buflen < 0)
-		return -ENAMETOOLONG;
-	*buffer -= namelen;
-	memcpy(*buffer, str, namelen);
-	return 0;
+	if (likely(*buflen >= 0)) {
+		*buffer -= namelen;
+		memcpy(*buffer, str, namelen);
+	}
 }
 
 /**
@@ -298,11 +297,10 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
 {
 	char *end = buffer + buflen;
 	/* these dentries are never renamed, so d_lock is not needed */
-	if (prepend(&end, &buflen, " (deleted)", 11) ||
-	    prepend(&end, &buflen, dentry->d_name.name, dentry->d_name.len) ||
-	    prepend(&end, &buflen, "/", 1))  
-		end = ERR_PTR(-ENAMETOOLONG);
-	return end;
+	prepend(&end, &buflen, " (deleted)", 11);
+	prepend(&end, &buflen, dentry->d_name.name, dentry->d_name.len);
+	prepend(&end, &buflen, "/", 1);
+	return buflen >= 0 ? end : ERR_PTR(-ENAMETOOLONG);
 }
 
 /*
-- 
2.11.0