Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs pile 1 from Al Viro:
 "This is _not_ all; in particular, Miklos' and Jan's stuff is not there
  yet."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
  ext4: initialization of ext4_li_mtx needs to be done earlier
  debugfs-related mode_t whack-a-mole
  hfsplus: add an ioctl to bless files
  hfsplus: change finder_info to u32
  hfsplus: initialise userflags
  qnx4: new helper - try_extent()
  qnx4: get rid of qnx4_bread/qnx4_getblk
  take removal of PF_FORKNOEXEC to flush_old_exec()
  trim includes in inode.c
  um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it
  um: embed ->stub_pages[] into mmu_context
  gadgetfs: list_for_each_safe() misuse
  ocfs2: fix leaks on failure exits in module_init
  ecryptfs: make register_filesystem() the last potential failure exit
  ntfs: forgets to unregister sysctls on register_filesystem() failure
  logfs: missing cleanup on register_filesystem() failure
  jfs: mising cleanup on register_filesystem() failure
  make configfs_pin_fs() return root dentry on success
  configfs: configfs_create_dir() has parent dentry in dentry->d_parent
  configfs: sanitize configfs_create()
  ...

3 files changed, 16 insertions, 22 deletions

diff --git a/arch/um/include/asm/mmu.h b/arch/um/include/asm/mmu.h
index 30509b9f37fd..53e8b498ebba 100644
--- a/arch/um/include/asm/mmu.h
+++ b/arch/um/include/asm/mmu.h
@@ -12,7 +12,7 @@
 typedef struct mm_context {
         struct mm_id id;
         struct uml_arch_mm_context arch;
-        struct page **stub_pages;
+        struct page *stub_pages[2];
 } mm_context_t;
 
 extern void __switch_mm(struct mm_id * mm_idp);
diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h
index 591b3d8d7614..aa4a743dc4ab 100644
--- a/arch/um/include/asm/mmu_context.h
+++ b/arch/um/include/asm/mmu_context.h
@@ -9,7 +9,7 @@
 #include <linux/sched.h>
 #include <asm/mmu.h>
 
-extern void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm);
+extern void uml_setup_stubs(struct mm_struct *mm);
 extern void arch_exit_mmap(struct mm_struct *mm);
 
 #define deactivate_mm(tsk,mm)   do { } while (0)
@@ -23,7 +23,9 @@ static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
          * when the new ->mm is used for the first time.
          */
         __switch_mm(&new->context.id);
-        arch_dup_mmap(old, new);
+        down_write(&new->mmap_sem);
+        uml_setup_stubs(new);
+        up_write(&new->mmap_sem);
 }
 
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, 
@@ -39,6 +41,11 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
         }
 }
 
+static inline void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+{
+        uml_setup_stubs(mm);
+}
+
 static inline void enter_lazy_tlb(struct mm_struct *mm, 
                                   struct task_struct *tsk)
 {
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 1aee587e9c5d..4947b319f53a 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -92,8 +92,6 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
                 goto out_free;
         }
 
-        to_mm->stub_pages = NULL;
-
         return 0;
 
  out_free:
@@ -103,7 +101,7 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
         return ret;
 }
 
-void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+void uml_setup_stubs(struct mm_struct *mm)
 {
         struct page **pages;
         int err, ret;
@@ -120,29 +118,20 @@ void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
         if (ret)
                 goto out;
 
-        pages = kmalloc(2 * sizeof(struct page *), GFP_KERNEL);
-        if (pages == NULL) {
-                printk(KERN_ERR "arch_dup_mmap failed to allocate 2 page "
-                       "pointers\n");
-                goto out;
-        }
-
-        pages[0] = virt_to_page(&__syscall_stub_start);
-        pages[1] = virt_to_page(mm->context.id.stack);
-        mm->context.stub_pages = pages;
+        mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
+        mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
 
         /* dup_mmap already holds mmap_sem */
         err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
                                       VM_READ | VM_MAYREAD | VM_EXEC |
-                                      VM_MAYEXEC | VM_DONTCOPY, pages);
+                                      VM_MAYEXEC | VM_DONTCOPY,
+                                      mm->context.stub_pages);
         if (err) {
                 printk(KERN_ERR "install_special_mapping returned %d\n", err);
-                goto out_free;
+                goto out;
         }
         return;
 
-out_free:
-        kfree(pages);
 out:
         force_sigsegv(SIGSEGV, current);
 }
@@ -151,8 +140,6 @@ void arch_exit_mmap(struct mm_struct *mm)
 {
         pte_t *pte;
 
-        if (mm->context.stub_pages != NULL)
-                kfree(mm->context.stub_pages);
         pte = virt_to_pte(mm, STUB_CODE);
         if (pte != NULL)
                 pte_clear(mm, STUB_CODE, pte);