From: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Date: Mon, 22 Jun 2020 15:18:35 +0000 (+0200)
Subject: bus-message: add macro for calculation of offset from the page
X-Git-Tag: v246-rc1~125^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b98f393d88262dc7afc321ac48c228d3b67b0178;p=thirdparty%2Fsystemd.git

bus-message: add macro for calculation of offset from the page
---

diff --git a/src/basic/memory-util.h b/src/basic/memory-util.h
index a6a2ccdbc29..4f596cffb75 100644
--- a/src/basic/memory-util.h
+++ b/src/basic/memory-util.h
@@ -13,6 +13,7 @@
 size_t page_size(void) _pure_;
 #define PAGE_ALIGN(l) ALIGN_TO((l), page_size())
 #define PAGE_ALIGN_DOWN(l) ((l) & ~(page_size() - 1))
+#define PAGE_OFFSET(l) ((l) & (page_size() - 1))
 
 /* Normal memcpy requires src to be nonnull. We do nothing if n is 0. */
 static inline void memcpy_safe(void *dst, const void *src, size_t n) {
diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 8a8fbde7810..55e35cd902e 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -3022,7 +3022,7 @@ int bus_body_part_map(struct bus_body_part *part) {
                 return 0;
         }
 
-        shift = part->memfd_offset - ((part->memfd_offset / page_size()) * page_size());
+        shift = PAGE_OFFSET(part->memfd_offset);
         psz = PAGE_ALIGN(part->size + shift);
 
         if (part->memfd >= 0)