[Devel] [PATCH 01/13] mm: introduce check_data_rlimit helper

[Andrew Vagin]

From: Cyrill Gorcunov <gorcunov at openvz.org>

ML: 9c5990240e076ae564cccbd921868cd08f6daaa5

To eliminate code duplication lets introduce check_data_rlimit helper
which we will use in brk() and prctl() syscalls.

Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
Cc: Kees Cook <keescook at chromium.org>
Cc: Tejun Heo <tj at kernel.org>
Cc: Andrew Vagin <avagin at openvz.org>
Cc: Eric W. Biederman <ebiederm at xmission.com>
Cc: H. Peter Anvin <hpa at zytor.com>
Acked-by: Serge Hallyn <serge.hallyn at canonical.com>
Cc: Pavel Emelyanov <xemul at parallels.com>
Cc: Vasiliy Kulikov <segoon at openwall.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpages at gmail.com>
Cc: Julien Tinnes <jln at google.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Andrew Vagin <avagin at openvz.org>
---
 include/linux/mm.h |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8424c6a..163d3d8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -18,6 +18,7 @@
 #include <linux/pfn.h>
 #include <linux/bit_spinlock.h>
 #include <linux/shrinker.h>
+#include <linux/resource.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -1747,6 +1748,20 @@ extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
 	bool *need_rmap_locks);
 extern void exit_mmap(struct mm_struct *);
 
+static inline int check_data_rlimit(unsigned long rlim,
+				    unsigned long new,
+				    unsigned long start,
+				    unsigned long end_data,
+				    unsigned long start_data)
+{
+	if (rlim < RLIM_INFINITY) {
+		if (((new - start) + (end_data - start_data)) > rlim)
+			return -ENOSPC;
+	}
+
+	return 0;
+}
+
 extern int mm_take_all_locks(struct mm_struct *mm);
 extern void mm_drop_all_locks(struct mm_struct *mm);
 
-- 
1.7.1