From: Emil Velikov <emil.l.velikov@gmail.com>
Date: Sun, 2 Aug 2026 12:26:13 +0000 (+0100)
Subject: shared/strbuf: introduce and use ALIGN
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ea30e6681fe729eba4623649aa8651fb5ce5c7a7;p=thirdparty%2Fkmod.git

shared/strbuf: introduce and use ALIGN

Introduce the simple macro and use it to (better) illustrate the strbuf
size calculation.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/451
Signed-off-by: Lucas De Marchi <demarchi@kernel.org>
---

diff --git a/shared/macro.h b/shared/macro.h
index 83e9d9d..46861ff 100644
--- a/shared/macro.h
+++ b/shared/macro.h
@@ -31,6 +31,9 @@
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + _array_size_chk(arr))
 
+#define _ALIGN_MASK(x, _MASK) (((x) + (_MASK)) & ~(_MASK))
+#define ALIGN(x, B) _ALIGN_MASK(x, (typeof(x))(B) - 1)
+
 #define XSTRINGIFY(x) #x
 #define STRINGIFY(x) XSTRINGIFY(x)
 
diff --git a/shared/strbuf.c b/shared/strbuf.c
index 4c3b55c..76aab07 100644
--- a/shared/strbuf.c
+++ b/shared/strbuf.c
@@ -10,8 +10,9 @@
 #include <string.h>
 #include <sys/param.h>
 
-#include "util.h"
+#include "macro.h"
 #include "strbuf.h"
+#include "util.h"
 
 #define BUF_STEP 128
 
@@ -42,8 +43,7 @@ static bool strbuf_reserve_extra(struct strbuf *buf, size_t n)
 	    n > SIZE_MAX - BUF_STEP)
 		return false;
 
-	if (n % BUF_STEP)
-		n = ((n / BUF_STEP) + 1) * BUF_STEP;
+	n = ALIGN(n, BUF_STEP);
 
 	return buf_realloc(buf, n);
 }