VM: make zap_page_range() callers that act on a single VMA use separate helper
... and not rely on ->vm_next being there for them...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/memory.c b/mm/memory.c
index 016c675..8ab0918 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1307,6 +1307,47 @@
mem_cgroup_uncharge_end();
}
+
+static void unmap_single_vma(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, unsigned long start_addr,
+ unsigned long end_addr, unsigned long *nr_accounted,
+ struct zap_details *details)
+{
+ unsigned long start = max(vma->vm_start, start_addr);
+ unsigned long end;
+
+ if (start >= vma->vm_end)
+ return;
+ end = min(vma->vm_end, end_addr);
+ if (end <= vma->vm_start)
+ return;
+
+ if (vma->vm_flags & VM_ACCOUNT)
+ *nr_accounted += (end - start) >> PAGE_SHIFT;
+
+ if (unlikely(is_pfn_mapping(vma)))
+ untrack_pfn_vma(vma, 0, 0);
+
+ if (start != end) {
+ if (unlikely(is_vm_hugetlb_page(vma))) {
+ /*
+ * It is undesirable to test vma->vm_file as it
+ * should be non-null for valid hugetlb area.
+ * However, vm_file will be NULL in the error
+ * cleanup path of do_mmap_pgoff. When
+ * hugetlbfs ->mmap method fails,
+ * do_mmap_pgoff() nullifies vma->vm_file
+ * before calling this function to clean up.
+ * Since no pte has actually been setup, it is
+ * safe to do nothing in this case.
+ */
+ if (vma->vm_file)
+ unmap_hugepage_range(vma, start, end, NULL);
+ } else
+ unmap_page_range(tlb, vma, start, end, details);
+ }
+}
+
/**
* unmap_vmas - unmap a range of memory covered by a list of vma's
* @tlb: address of the caller's struct mmu_gather
@@ -1332,46 +1373,12 @@
unsigned long end_addr, unsigned long *nr_accounted,
struct zap_details *details)
{
- unsigned long start = start_addr;
struct mm_struct *mm = vma->vm_mm;
mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
- for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
- unsigned long end;
-
- start = max(vma->vm_start, start_addr);
- if (start >= vma->vm_end)
- continue;
- end = min(vma->vm_end, end_addr);
- if (end <= vma->vm_start)
- continue;
-
- if (vma->vm_flags & VM_ACCOUNT)
- *nr_accounted += (end - start) >> PAGE_SHIFT;
-
- if (unlikely(is_pfn_mapping(vma)))
- untrack_pfn_vma(vma, 0, 0);
-
- if (start != end) {
- if (unlikely(is_vm_hugetlb_page(vma))) {
- /*
- * It is undesirable to test vma->vm_file as it
- * should be non-null for valid hugetlb area.
- * However, vm_file will be NULL in the error
- * cleanup path of do_mmap_pgoff. When
- * hugetlbfs ->mmap method fails,
- * do_mmap_pgoff() nullifies vma->vm_file
- * before calling this function to clean up.
- * Since no pte has actually been setup, it is
- * safe to do nothing in this case.
- */
- if (vma->vm_file)
- unmap_hugepage_range(vma, start, end, NULL);
- } else
- unmap_page_range(tlb, vma, start, end, details);
- }
- }
-
+ for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
+ unmap_single_vma(tlb, vma, start_addr, end_addr, nr_accounted,
+ details);
mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
}
@@ -1381,6 +1388,8 @@
* @address: starting address of pages to zap
* @size: number of bytes to zap
* @details: details of nonlinear truncation or shared cache invalidation
+ *
+ * Caller must protect the VMA list
*/
void zap_page_range(struct vm_area_struct *vma, unsigned long address,
unsigned long size, struct zap_details *details)
@@ -1398,6 +1407,32 @@
}
/**
+ * zap_page_range_single - remove user pages in a given range
+ * @vma: vm_area_struct holding the applicable pages
+ * @address: starting address of pages to zap
+ * @size: number of bytes to zap
+ * @details: details of nonlinear truncation or shared cache invalidation
+ *
+ * The range must fit into one VMA.
+ */
+static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
+ unsigned long size, struct zap_details *details)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct mmu_gather tlb;
+ unsigned long end = address + size;
+ unsigned long nr_accounted = 0;
+
+ lru_add_drain();
+ tlb_gather_mmu(&tlb, mm, 0);
+ update_hiwater_rss(mm);
+ mmu_notifier_invalidate_range_start(mm, address, end);
+ unmap_single_vma(&tlb, vma, address, end, &nr_accounted, details);
+ mmu_notifier_invalidate_range_end(mm, address, end);
+ tlb_finish_mmu(&tlb, address, end);
+}
+
+/**
* zap_vma_ptes - remove ptes mapping the vma
* @vma: vm_area_struct holding ptes to be zapped
* @address: starting address of pages to zap
@@ -1415,7 +1450,7 @@
if (address < vma->vm_start || address + size > vma->vm_end ||
!(vma->vm_flags & VM_PFNMAP))
return -1;
- zap_page_range(vma, address, size, NULL);
+ zap_page_range_single(vma, address, size, NULL);
return 0;
}
EXPORT_SYMBOL_GPL(zap_vma_ptes);
@@ -2762,7 +2797,7 @@
unsigned long start_addr, unsigned long end_addr,
struct zap_details *details)
{
- zap_page_range(vma, start_addr, end_addr - start_addr, details);
+ zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
}
static inline void unmap_mapping_range_tree(struct prio_tree_root *root,