[PATCH 21/64] mm: teach drop/take_all_locks() about range locking

[Davidlohr Bueso]

From: Davidlohr Bueso <d...@stgolabs.net>

And use the mm locking helpers. No changes in semantics.

Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
---
 include/linux/mm.h |  6 ++++--
 mm/mmap.c          | 12 +++++++-----
 mm/mmu_notifier.c  |  9 +++++----
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index fc4e7fdc3e76..0b9867e8a35d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2198,8 +2198,10 @@ static inline int check_data_rlimit(unsigned long rlim,
        return 0;
 }
 
-extern int mm_take_all_locks(struct mm_struct *mm);
-extern void mm_drop_all_locks(struct mm_struct *mm);
+extern int mm_take_all_locks(struct mm_struct *mm,
+                            struct range_lock *mmrange);
+extern void mm_drop_all_locks(struct mm_struct *mm,
+                             struct range_lock *mmrange);
 
 extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
 extern struct file *get_mm_exe_file(struct mm_struct *mm);
diff --git a/mm/mmap.c b/mm/mmap.c
index f61d49cb791e..8f0eb88a5d5e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3461,12 +3461,13 @@ static void vm_lock_mapping(struct mm_struct *mm, 
struct address_space *mapping)
  *
  * mm_take_all_locks() can fail if it's interrupted by signals.
  */
-int mm_take_all_locks(struct mm_struct *mm)
+int mm_take_all_locks(struct mm_struct *mm,
+                     struct range_lock *mmrange)
 {
        struct vm_area_struct *vma;
        struct anon_vma_chain *avc;
 
-       BUG_ON(down_read_trylock(&mm->mmap_sem));
+       BUG_ON(mm_read_trylock(mm, mmrange));
 
        mutex_lock(&mm_all_locks_mutex);
 
@@ -3497,7 +3498,7 @@ int mm_take_all_locks(struct mm_struct *mm)
        return 0;
 
 out_unlock:
-       mm_drop_all_locks(mm);
+       mm_drop_all_locks(mm, mmrange);
        return -EINTR;
 }
 
@@ -3541,12 +3542,13 @@ static void vm_unlock_mapping(struct address_space 
*mapping)
  * The mmap_sem cannot be released by the caller until
  * mm_drop_all_locks() returns.
  */
-void mm_drop_all_locks(struct mm_struct *mm)
+void mm_drop_all_locks(struct mm_struct *mm,
+                      struct range_lock *mmrange)
 {
        struct vm_area_struct *vma;
        struct anon_vma_chain *avc;
 
-       BUG_ON(down_read_trylock(&mm->mmap_sem));
+       BUG_ON(mm_read_trylock(mm, mmrange));
        BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
 
        for (vma = mm->mmap; vma; vma = vma->vm_next) {
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 3e8a1a10607e..da99c01b8149 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -274,6 +274,7 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn,
 {
        struct mmu_notifier_mm *mmu_notifier_mm;
        int ret;
+       DEFINE_RANGE_LOCK_FULL(mmrange);
 
        BUG_ON(atomic_read(&mm->mm_users) <= 0);
 
@@ -283,8 +284,8 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn,
                goto out;
 
        if (take_mmap_sem)
-               down_write(&mm->mmap_sem);
-       ret = mm_take_all_locks(mm);
+               mm_write_lock(mm, &mmrange);
+       ret = mm_take_all_locks(mm, &mmrange);
        if (unlikely(ret))
                goto out_clean;
 
@@ -309,10 +310,10 @@ static int do_mmu_notifier_register(struct mmu_notifier 
*mn,
        hlist_add_head(&mn->hlist, &mm->mmu_notifier_mm->list);
        spin_unlock(&mm->mmu_notifier_mm->lock);
 
-       mm_drop_all_locks(mm);
+       mm_drop_all_locks(mm, &mmrange);
 out_clean:
        if (take_mmap_sem)
-               up_write(&mm->mmap_sem);
+               mm_write_unlock(mm, &mmrange);
        kfree(mmu_notifier_mm);
 out:
        BUG_ON(atomic_read(&mm->mm_users) <= 0);
-- 
2.13.6