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mm: make expand_downwards() symmetrical with expand_upwards()

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Currently we have expand_upwards exported while expand_downwards is
accessible only via expand_stack or expand_stack_downwards.

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 clean this up by exporting both functions and make those names
consistent.  Let's use expand_{upwards,downwards} because expanding
doesn't always involve stack manipulation (an example is
ia64_do_page_fault which uses expand_upwards for registers backing store
expansion).  expand_downwards has to be defined for both
CONFIG_STACK_GROWS{UP,DOWN} because get_arg_page calls the downwards
version in the early process initialization phase for growsup
configuration.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michal Hocko
2011-05-24 17:11:44 -07:00
committed by Linus Torvalds
parent 248ac0e194
commit d05f3169c0
4 changed files with 8 additions and 11 deletions
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7
mm/mmap.c
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@ -1774,7 +1774,7 @@ 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;
@ -1821,11 +1821,6 @@ static int expand_downwards(struct vm_area_struct *vma,
return error;
}
int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
{
return expand_downwards(vma, address);
}
#ifdef CONFIG_STACK_GROWSUP
int expand_stack(struct vm_area_struct *vma, unsigned long address)
{