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Subject[PATCH] mm: make expand_downwards symmetrical to expand_upwards
Hi,
the following patch is just a cleanup for better readability without any
functional changes. What do you think about it?
---
From 71de71aaa725ee87459b3a256e8bb0af7de4abeb Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@suse.cz>
Date: Fri, 15 Apr 2011 14:56:26 +0200
Subject: [PATCH] mm: make expand_downwards symmetrical to expand_upwards
Currently we have expand_upwards exported while expand_downwards is
accessible only via expand_stack.

check_stack_guard_page is a nice example of the asymmetry. It uses
expand_stack for VM_GROWSDOWN while expand_upwards is called for
VM_GROWSUP case. Let's make this consistent and export expand_downwards
same way we do with expand_upwards.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
---
include/linux/mm.h | 2 ++
mm/memory.c | 2 +-
mm/mmap.c | 2 +-
3 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 692dbae..765cf4e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1498,8 +1498,10 @@ unsigned long ra_submit(struct file_ra_state *ra,
extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
#if VM_GROWSUP
extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
+ #define expand_downwards(vma, address) do { } while (0)
#else
#define expand_upwards(vma, address) do { } while (0)
+extern int expand_downwards(struct vm_area_struct *vma, unsigned long address);
#endif
extern int expand_stack_downwards(struct vm_area_struct *vma,
unsigned long address);
diff --git a/mm/memory.c b/mm/memory.c
index ce22a25..f404fb6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2969,7 +2969,7 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo
if (prev && prev->vm_end == address)
return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;

- expand_stack(vma, address - PAGE_SIZE);
+ expand_downwards(vma, address - PAGE_SIZE);
}
if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
struct vm_area_struct *next = vma->vm_next;
diff --git a/mm/mmap.c b/mm/mmap.c
index e27e0cf..6b2a817 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1782,7 +1782,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
/*
* vma is the first one with address < vma->vm_start. Have to extend vma.
*/
-static int expand_downwards(struct vm_area_struct *vma,
+int expand_downwards(struct vm_area_struct *vma,
unsigned long address)
{
int error;
--
1.7.4.1
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic


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