mm rmap: remove vma_address check for address inside vma
In file and anon rmap, we use interval trees to find potentially relevant
vmas and then call vma_address() to find the virtual address the given
page might be found at in these vmas. vma_address() used to include a
check that the returned address falls within the limits of the vma, but
this check isn't necessary now that we always use interval trees in rmap:
the interval tree just doesn't return any vmas which this check would find
to be irrelevant. As a result, we can replace the use of -EFAULT error
code (which then needed to be checked in every call site) with a
VM_BUG_ON().
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/rmap.c b/mm/rmap.c
index 9c61bf3..2877741 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -510,22 +510,26 @@
/*
* At what user virtual address is page expected in @vma?
- * Returns virtual address or -EFAULT if page's index/offset is not
- * within the range mapped the @vma.
*/
-inline unsigned long
-vma_address(struct page *page, struct vm_area_struct *vma)
+static inline unsigned long
+__vma_address(struct page *page, struct vm_area_struct *vma)
{
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
- unsigned long address;
if (unlikely(is_vm_hugetlb_page(vma)))
pgoff = page->index << huge_page_order(page_hstate(page));
- address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
- if (unlikely(address < vma->vm_start || address >= vma->vm_end)) {
- /* page should be within @vma mapping range */
- return -EFAULT;
- }
+
+ return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+}
+
+inline unsigned long
+vma_address(struct page *page, struct vm_area_struct *vma)
+{
+ unsigned long address = __vma_address(page, vma);
+
+ /* page should be within @vma mapping range */
+ VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
+
return address;
}
@@ -535,6 +539,7 @@
*/
unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
{
+ unsigned long address;
if (PageAnon(page)) {
struct anon_vma *page__anon_vma = page_anon_vma(page);
/*
@@ -550,7 +555,10 @@
return -EFAULT;
} else
return -EFAULT;
- return vma_address(page, vma);
+ address = __vma_address(page, vma);
+ if (unlikely(address < vma->vm_start || address >= vma->vm_end))
+ return -EFAULT;
+ return address;
}
/*
@@ -624,8 +632,8 @@
pte_t *pte;
spinlock_t *ptl;
- address = vma_address(page, vma);
- if (address == -EFAULT) /* out of vma range */
+ address = __vma_address(page, vma);
+ if (unlikely(address < vma->vm_start || address >= vma->vm_end))
return 0;
pte = page_check_address(page, vma->vm_mm, address, &ptl, 1);
if (!pte) /* the page is not in this mm */
@@ -732,8 +740,6 @@
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
/*
* If we are reclaiming on behalf of a cgroup, skip
* counting on behalf of references from different
@@ -799,8 +805,6 @@
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
/*
* If we are reclaiming on behalf of a cgroup, skip
* counting on behalf of references from different
@@ -904,8 +908,6 @@
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
if (vma->vm_flags & VM_SHARED) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret += page_mkclean_one(page, vma, address);
}
}
@@ -1468,8 +1470,6 @@
continue;
address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = try_to_unmap_one(page, vma, address, flags);
if (ret != SWAP_AGAIN || !page_mapped(page))
break;
@@ -1508,8 +1508,6 @@
mutex_lock(&mapping->i_mmap_mutex);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = try_to_unmap_one(page, vma, address, flags);
if (ret != SWAP_AGAIN || !page_mapped(page))
goto out;
@@ -1684,8 +1682,6 @@
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = rmap_one(page, vma, address, arg);
if (ret != SWAP_AGAIN)
break;
@@ -1707,8 +1703,6 @@
mutex_lock(&mapping->i_mmap_mutex);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = rmap_one(page, vma, address, arg);
if (ret != SWAP_AGAIN)
break;