Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6

[pandora-kernel.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 51a5c23..b623a24 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1410,6 +1410,13 @@ no_page_table:
        return page;
 }
 
+static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
+{
+       return (vma->vm_flags & VM_GROWSDOWN) &&
+               (vma->vm_start == addr) &&
+               !vma_stack_continue(vma->vm_prev, addr);
+}
+
 /**
  * __get_user_pages() - pin user pages in memory
  * @tsk:       task_struct of target task
@@ -1488,7 +1495,6 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                vma = find_extend_vma(mm, start);
                if (!vma && in_gate_area(mm, start)) {
                        unsigned long pg = start & PAGE_MASK;
-                       struct vm_area_struct *gate_vma = get_gate_vma(mm);
                        pgd_t *pgd;
                        pud_t *pud;
                        pmd_t *pmd;
@@ -1513,10 +1519,11 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                pte_unmap(pte);
                                return i ? : -EFAULT;
                        }
+                       vma = get_gate_vma(mm);
                        if (pages) {
                                struct page *page;
 
-                               page = vm_normal_page(gate_vma, start, *pte);
+                               page = vm_normal_page(vma, start, *pte);
                                if (!page) {
                                        if (!(gup_flags & FOLL_DUMP) &&
                                             is_zero_pfn(pte_pfn(*pte)))
@@ -1530,12 +1537,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                get_page(page);
                        }
                        pte_unmap(pte);
-                       if (vmas)
-                               vmas[i] = gate_vma;
-                       i++;
-                       start += PAGE_SIZE;
-                       nr_pages--;
-                       continue;
+                       goto next_page;
                }
 
                if (!vma ||
@@ -1549,6 +1551,13 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                        continue;
                }
 
+               /*
+                * If we don't actually want the page itself,
+                * and it's the stack guard page, just skip it.
+                */
+               if (!pages && stack_guard_page(vma, start))
+                       goto next_page;
+
                do {
                        struct page *page;
                        unsigned int foll_flags = gup_flags;
@@ -1631,6 +1640,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                flush_anon_page(vma, page, start);
                                flush_dcache_page(page);
                        }
+next_page:
                        if (vmas)
                                vmas[i] = vma;
                        i++;
@@ -3715,7 +3725,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
 }
 
 /**
- * @access_remote_vm - access another process' address space
+ * access_remote_vm - access another process' address space
  * @mm:                the mm_struct of the target address space
  * @addr:      start address to access
  * @buf:       source or destination buffer