linux-kernel - [PATCH 7/7] lib/bitmap.c: simplify bitmap_print_to

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Date:   Sat, 18 Aug 2018 15:16:23 +0200
From:   Rasmus Villemoes <linux@...musvillemoes.dk>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Yury Norov <ynorov@...iumnetworks.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Sudeep Holla <sudeep.holla@....com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 7/7] lib/bitmap.c: simplify bitmap_print_to_pagebuf

len is guaranteed to lie in [1, PAGE_SIZE]. If scnprintf is called with
a buffer size of 1, it is guaranteed to return 0. So in the extremely
unlikely case of having just one byte remaining in the page, let's just
call scnprintf anyway. The only difference is that this will write a
'\0' to that final byte in the page, but that's an improvement: We now
guarantee that after the call, buf is a properly terminated C string of
length exactly the return value.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
---
 lib/bitmap.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 277c9a63a5ab..75175da01fd8 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -469,12 +469,9 @@ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
 			    int nmaskbits)
 {
 	ptrdiff_t len = PAGE_SIZE - ((unsigned long)buf & (PAGE_SIZE-1));
-	int n = 0;
 
-	if (len > 1)
-		n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
-			   scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
-	return n;
+	return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
+		      scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
 }
 EXPORT_SYMBOL(bitmap_print_to_pagebuf);
 
-- 
2.16.4