mm: use may_adjust_brk helper

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

kernel/sys.c

@@ -1693,7 +1693,6 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
 static int prctl_set_mm(int opt, unsigned long addr,
 			unsigned long arg4, unsigned long arg5)
 {
-	unsigned long rlim = rlimit(RLIMIT_DATA);
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	int error;
@@ -1733,9 +1732,8 @@ static int prctl_set_mm(int opt, unsigned long addr,
 		if (addr <= mm->end_data)
 			goto out;
 
-		if (rlim < RLIM_INFINITY &&
-		    (mm->brk - addr) +
-		    (mm->end_data - mm->start_data) > rlim)
+		if (check_data_rlimit(rlimit(RLIMIT_DATA), mm->brk, addr,
+				      mm->end_data, mm->start_data))
 			goto out;
 
 		mm->start_brk = addr;
@@ -1745,9 +1743,8 @@ static int prctl_set_mm(int opt, unsigned long addr,
 		if (addr <= mm->end_data)
 			goto out;
 
-		if (rlim < RLIM_INFINITY &&
-		    (addr - mm->start_brk) +
-		    (mm->end_data - mm->start_data) > rlim)
+		if (check_data_rlimit(rlimit(RLIMIT_DATA), addr, mm->start_brk,
+				      mm->end_data, mm->start_data))
 			goto out;
 
 		mm->brk = addr;

mm/mmap.c

@@ -268,7 +268,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len);
 
 SYSCALL_DEFINE1(brk, unsigned long, brk)
 {
-	unsigned long rlim, retval;
+	unsigned long retval;
 	unsigned long newbrk, oldbrk;
 	struct mm_struct *mm = current->mm;
 	unsigned long min_brk;
@@ -298,9 +298,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
 	 * segment grow beyond its set limit the in case where the limit is
 	 * not page aligned -Ram Gupta
 	 */
-	rlim = rlimit(RLIMIT_DATA);
-	if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
-			(mm->end_data - mm->start_data) > rlim)
+	if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk,
+			      mm->end_data, mm->start_data))
 		goto out;
 
 	newbrk = PAGE_ALIGN(brk);