mm: make expand_downwards() symmetrical with expand_upwards()
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>
diff --git a/fs/exec.c b/fs/exec.c
index c1cf372..e276d5e 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -200,7 +200,7 @@
#ifdef CONFIG_STACK_GROWSUP
if (write) {
- ret = expand_stack_downwards(bprm->vma, pos);
+ ret = expand_downwards(bprm->vma, pos);
if (ret < 0)
return NULL;
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e173cd2..d2948af 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1518,15 +1518,17 @@
struct address_space *mapping,
struct file *filp);
-/* Do stack extension */
+/* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
+
+/* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
+extern int expand_downwards(struct vm_area_struct *vma,
+ unsigned long address);
#if VM_GROWSUP
extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
#else
#define expand_upwards(vma, address) do { } while (0)
#endif
-extern int expand_stack_downwards(struct vm_area_struct *vma,
- unsigned long address);
/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
diff --git a/mm/memory.c b/mm/memory.c
index 61e66f0..4c6ea10 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2966,7 +2966,7 @@
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 e76f8d7..adb1252 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1774,7 +1774,7 @@
/*
* 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 @@
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)
{