1 files changed, 27 insertions, 46 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 85d16c67c33e..fa95ab2d3674 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -259,23 +259,29 @@ static int do_maps_open(struct inode *inode, struct file *file,
                                 sizeof(struct proc_maps_private));
 }
 
-static pid_t pid_of_stack(struct proc_maps_private *priv,
-                                struct vm_area_struct *vma, bool is_pid)
+/*
+ * Indicate if the VMA is a stack for the given task; for
+ * /proc/PID/maps that is the stack of the main task.
+ */
+static int is_stack(struct proc_maps_private *priv,
+                    struct vm_area_struct *vma, int is_pid)
 {
-        struct inode *inode = priv->inode;
-        struct task_struct *task;
-        pid_t ret = 0;
+        int stack = 0;
+
+        if (is_pid) {
+                stack = vma->vm_start <= vma->vm_mm->start_stack &&
+                        vma->vm_end >= vma->vm_mm->start_stack;
+        } else {
+                struct inode *inode = priv->inode;
+                struct task_struct *task;
 
-        rcu_read_lock();
-        task = pid_task(proc_pid(inode), PIDTYPE_PID);
-        if (task) {
-                task = task_of_stack(task, vma, is_pid);
+                rcu_read_lock();
+                task = pid_task(proc_pid(inode), PIDTYPE_PID);
                 if (task)
-                        ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info);
+                        stack = vma_is_stack_for_task(vma, task);
+                rcu_read_unlock();
         }
-        rcu_read_unlock();
-
-        return ret;
+        return stack;
 }
 
 static void
@@ -335,8 +341,6 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
 
         name = arch_vma_name(vma);
         if (!name) {
-                pid_t tid;
-
                 if (!mm) {
                         name = "[vdso]";
                         goto done;
@@ -348,21 +352,8 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
                         goto done;
                 }
 
-                tid = pid_of_stack(priv, vma, is_pid);
-                if (tid != 0) {
-                        /*
-                         * Thread stack in /proc/PID/task/TID/maps or
-                         * the main process stack.
-                         */
-                        if (!is_pid || (vma->vm_start <= mm->start_stack &&
-                            vma->vm_end >= mm->start_stack)) {
-                                name = "[stack]";
-                        } else {
-                                /* Thread stack in /proc/PID/maps */
-                                seq_pad(m, ' ');
-                                seq_printf(m, "[stack:%d]", tid);
-                        }
-                }
+                if (is_stack(priv, vma, is_pid))
+                        name = "[stack]";
         }
 
 done:
@@ -1552,18 +1543,19 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
                 unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
+        pte_t huge_pte = huge_ptep_get(pte);
         struct numa_maps *md;
         struct page *page;
 
-        if (!pte_present(*pte))
+        if (!pte_present(huge_pte))
                 return 0;
 
-        page = pte_page(*pte);
+        page = pte_page(huge_pte);
         if (!page)
                 return 0;
 
         md = walk->private;
-        gather_stats(page, md, pte_dirty(*pte), 1);
+        gather_stats(page, md, pte_dirty(huge_pte), 1);
         return 0;
 }
 
@@ -1617,19 +1609,8 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
                 seq_file_path(m, file, "\n\t= ");
         } else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
                 seq_puts(m, " heap");
-        } else {
-                pid_t tid = pid_of_stack(proc_priv, vma, is_pid);
-                if (tid != 0) {
-                        /*
-                         * Thread stack in /proc/PID/task/TID/maps or
-                         * the main process stack.
-                         */
-                        if (!is_pid || (vma->vm_start <= mm->start_stack &&
-                            vma->vm_end >= mm->start_stack))
-                                seq_puts(m, " stack");
-                        else
-                                seq_printf(m, " stack:%d", tid);
-                }
+        } else if (is_stack(proc_priv, vma, is_pid)) {
+                seq_puts(m, " stack");
         }
 
         if (is_vm_hugetlb_page(vma))