mm: prevent mmap_cache race in find_vma()

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

diff --git a/mm/mmap.c b/mm/mmap.c
index a65efd4..dff37a6 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -22,7 +22,7 @@
 #include <linux/security.h>
 #include <linux/hugetlb.h>
 #include <linux/profile.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/mount.h>
 #include <linux/mempolicy.h>
 #include <linux/rmap.h>
@@ -1573,7 +1573,7 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
        if (mm) {
                /* Check the cache first. */
                /* (Cache hit rate is typically around 35%.) */
-               vma = mm->mmap_cache;
+               vma = ACCESS_ONCE(mm->mmap_cache);
                if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
                        struct rb_node * rb_node;
 
@@ -2558,7 +2558,6 @@ int mm_take_all_locks(struct mm_struct *mm)
 {
        struct vm_area_struct *vma;
        struct anon_vma_chain *avc;
-       int ret = -EINTR;
 
        BUG_ON(down_read_trylock(&mm->mmap_sem));
 
@@ -2579,13 +2578,11 @@ int mm_take_all_locks(struct mm_struct *mm)
                                vm_lock_anon_vma(mm, avc->anon_vma);
        }
 
-       ret = 0;
+       return 0;
 
 out_unlock:
-       if (ret)
-               mm_drop_all_locks(mm);
-
-       return ret;
+       mm_drop_all_locks(mm);
+       return -EINTR;
 }
 
 static void vm_unlock_anon_vma(struct anon_vma *anon_vma)