[Devel] [PATCH RHEL7 COMMIT] ms/mm: use may_adjust_brk helper

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-229.7.2.vz7.8.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.8.8
------>
commit 7ed80b3f04e73e8692127a134efade3101ec2122
Author: Cyrill Gorcunov <gorcunov at openvz.org>
Date:   Tue Oct 20 13:28:01 2015 +0400

    ms/mm: use may_adjust_brk helper
    
    This is needed for CRIU.
    
    ML: 8764b338b37524ab1a78aee527318ebee9762487
    
    https://jira.sw.ru/browse/PSBM-39834
    
    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: Cyrill Gorcunov <gorcunov at virtuozzo.com>
---
 kernel/sys.c | 11 ++++-------
 mm/mmap.c    |  7 +++----
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/kernel/sys.c b/kernel/sys.c
index 737d9da..9218fde 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2279,7 +2279,6 @@ out:
 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;
@@ -2330,9 +2329,8 @@ 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;
@@ -2342,9 +2340,8 @@ 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;
diff --git a/mm/mmap.c b/mm/mmap.c
index 7cc9812..8796ed6 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -272,7 +272,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len, int soft);
 
 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;
@@ -302,9 +302,8 @@ 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);