mm: avoid anon_vma_chain allocation under anon_vma lock

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

diff --git a/mm/rmap.c b/mm/rmap.c
index 68756a7..27dfd3b 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -112,9 +112,9 @@ static inline void anon_vma_free(struct anon_vma *anon_vma)
        kmem_cache_free(anon_vma_cachep, anon_vma);
 }
 
-static inline struct anon_vma_chain *anon_vma_chain_alloc(void)
+static inline struct anon_vma_chain *anon_vma_chain_alloc(gfp_t gfp)
 {
-       return kmem_cache_alloc(anon_vma_chain_cachep, GFP_KERNEL);
+       return kmem_cache_alloc(anon_vma_chain_cachep, gfp);
 }
 
 static void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
@@ -159,7 +159,7 @@ int anon_vma_prepare(struct vm_area_struct *vma)
                struct mm_struct *mm = vma->vm_mm;
                struct anon_vma *allocated;
 
-               avc = anon_vma_chain_alloc();
+               avc = anon_vma_chain_alloc(GFP_KERNEL);
                if (!avc)
                        goto out_enomem;
 
@@ -253,9 +253,14 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
        list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) {
                struct anon_vma *anon_vma;
 
-               avc = anon_vma_chain_alloc();
-               if (!avc)
-                       goto enomem_failure;
+               avc = anon_vma_chain_alloc(GFP_NOWAIT | __GFP_NOWARN);
+               if (unlikely(!avc)) {
+                       unlock_anon_vma_root(root);
+                       root = NULL;
+                       avc = anon_vma_chain_alloc(GFP_KERNEL);
+                       if (!avc)
+                               goto enomem_failure;
+               }
                anon_vma = pavc->anon_vma;
                root = lock_anon_vma_root(root, anon_vma);
                anon_vma_chain_link(dst, avc, anon_vma);
@@ -264,7 +269,6 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
        return 0;
 
  enomem_failure:
-       unlock_anon_vma_root(root);
        unlink_anon_vmas(dst);
        return -ENOMEM;
 }
@@ -294,7 +298,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
        anon_vma = anon_vma_alloc();
        if (!anon_vma)
                goto out_error;
-       avc = anon_vma_chain_alloc();
+       avc = anon_vma_chain_alloc(GFP_KERNEL);
        if (!avc)
                goto out_error_free_anon_vma;