1 files changed, 55 insertions, 28 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 17403629e330..ab8ccc9d14ff 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -315,9 +315,9 @@ struct mem_size_stats {
 };
 
 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
-                           void *private)
+                           struct mm_walk *walk)
 {
-        struct mem_size_stats *mss = private;
+        struct mem_size_stats *mss = walk->private;
         struct vm_area_struct *vma = mss->vma;
         pte_t *pte, ptent;
         spinlock_t *ptl;
@@ -365,19 +365,21 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
         return 0;
 }
 
-static struct mm_walk smaps_walk = { .pmd_entry = smaps_pte_range };
-
 static int show_smap(struct seq_file *m, void *v)
 {
         struct vm_area_struct *vma = v;
         struct mem_size_stats mss;
         int ret;
+        struct mm_walk smaps_walk = {
+                .pmd_entry = smaps_pte_range,
+                .mm = vma->vm_mm,
+                .private = &mss,
+        };
 
         memset(&mss, 0, sizeof mss);
         mss.vma = vma;
         if (vma->vm_mm && !is_vm_hugetlb_page(vma))
-                walk_page_range(vma->vm_mm, vma->vm_start, vma->vm_end,
-                                &smaps_walk, &mss);
+                walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
 
         ret = show_map(m, v);
         if (ret)
@@ -426,9 +428,9 @@ const struct file_operations proc_smaps_operations = {
 };
 
 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
-                                unsigned long end, void *private)
+                                unsigned long end, struct mm_walk *walk)
 {
-        struct vm_area_struct *vma = private;
+        struct vm_area_struct *vma = walk->private;
         pte_t *pte, ptent;
         spinlock_t *ptl;
         struct page *page;
@@ -452,8 +454,6 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
         return 0;
 }
 
-static struct mm_walk clear_refs_walk = { .pmd_entry = clear_refs_pte_range };
-
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
@@ -476,11 +476,17 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
                 return -ESRCH;
         mm = get_task_mm(task);
         if (mm) {
+                static struct mm_walk clear_refs_walk;
+                memset(&clear_refs_walk, 0, sizeof(clear_refs_walk));
+                clear_refs_walk.pmd_entry = clear_refs_pte_range;
+                clear_refs_walk.mm = mm;
                 down_read(&mm->mmap_sem);
-                for (vma = mm->mmap; vma; vma = vma->vm_next)
+                for (vma = mm->mmap; vma; vma = vma->vm_next) {
+                        clear_refs_walk.private = vma;
                         if (!is_vm_hugetlb_page(vma))
-                                walk_page_range(mm, vma->vm_start, vma->vm_end,
-                                                &clear_refs_walk, vma);
+                                walk_page_range(vma->vm_start, vma->vm_end,
+                                                &clear_refs_walk);
+                }
                 flush_tlb_mm(mm);
                 up_read(&mm->mmap_sem);
                 mmput(mm);
@@ -528,9 +534,9 @@ static int add_to_pagemap(unsigned long addr, u64 pfn,
 }
 
 static int pagemap_pte_hole(unsigned long start, unsigned long end,
-                                void *private)
+                                struct mm_walk *walk)
 {
-        struct pagemapread *pm = private;
+        struct pagemapread *pm = walk->private;
         unsigned long addr;
         int err = 0;
         for (addr = start; addr < end; addr += PAGE_SIZE) {
@@ -547,24 +553,45 @@ static u64 swap_pte_to_pagemap_entry(pte_t pte)
         return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);
 }
 
+static unsigned long pte_to_pagemap_entry(pte_t pte)
+{
+        unsigned long pme = 0;
+        if (is_swap_pte(pte))
+                pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte))
+                        | PM_PSHIFT(PAGE_SHIFT) | PM_SWAP;
+        else if (pte_present(pte))
+                pme = PM_PFRAME(pte_pfn(pte))
+                        | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;
+        return pme;
+}
+
 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
-                             void *private)
+                             struct mm_walk *walk)
 {
-        struct pagemapread *pm = private;
+        struct vm_area_struct *vma;
+        struct pagemapread *pm = walk->private;
         pte_t *pte;
         int err = 0;
 
+        /* find the first VMA at or above 'addr' */
+        vma = find_vma(walk->mm, addr);
         for (; addr != end; addr += PAGE_SIZE) {
                 u64 pfn = PM_NOT_PRESENT;
-                pte = pte_offset_map(pmd, addr);
-                if (is_swap_pte(*pte))
-                        pfn = PM_PFRAME(swap_pte_to_pagemap_entry(*pte))
-                                | PM_PSHIFT(PAGE_SHIFT) | PM_SWAP;
-                else if (pte_present(*pte))
-                        pfn = PM_PFRAME(pte_pfn(*pte))
-                                | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;
-                /* unmap so we're not in atomic when we copy to userspace */
-                pte_unmap(pte);
+
+                /* check to see if we've left 'vma' behind
+                 * and need a new, higher one */
+                if (vma && (addr >= vma->vm_end))
+                        vma = find_vma(walk->mm, addr);
+
+                /* check that 'vma' actually covers this address,
+                 * and that it isn't a huge page vma */
+                if (vma && (vma->vm_start <= addr) &&
+                    !is_vm_hugetlb_page(vma)) {
+                        pte = pte_offset_map(pmd, addr);
+                        pfn = pte_to_pagemap_entry(*pte);
+                        /* unmap before userspace copy */
+                        pte_unmap(pte);
+                }
                 err = add_to_pagemap(addr, pfn, pm);
                 if (err)
                         return err;
@@ -675,8 +702,8 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
                  * user buffer is tracked in "pm", and the walk
                  * will stop when we hit the end of the buffer.
                  */
-                ret = walk_page_range(mm, start_vaddr, end_vaddr,
-                                        &pagemap_walk, &pm);
+                ret = walk_page_range(start_vaddr, end_vaddr,
+                                        &pagemap_walk);
                 if (ret == PM_END_OF_BUFFER)
                         ret = 0;
                 /* don't need mmap_sem for these, but this looks cleaner */