crypto: UML build fixes

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

diff --git a/mm/rmap.c b/mm/rmap.c
index f286697..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;
 
@@ -324,36 +328,43 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
        return -ENOMEM;
 }
 
-static void anon_vma_unlink(struct anon_vma_chain *anon_vma_chain)
-{
-       struct anon_vma *anon_vma = anon_vma_chain->anon_vma;
-       int empty;
-
-       /* If anon_vma_fork fails, we can get an empty anon_vma_chain. */
-       if (!anon_vma)
-               return;
-
-       anon_vma_lock(anon_vma);
-       list_del(&anon_vma_chain->same_anon_vma);
-
-       /* We must garbage collect the anon_vma if it's empty */
-       empty = list_empty(&anon_vma->head);
-       anon_vma_unlock(anon_vma);
-
-       if (empty)
-               put_anon_vma(anon_vma);
-}
-
 void unlink_anon_vmas(struct vm_area_struct *vma)
 {
        struct anon_vma_chain *avc, *next;
+       struct anon_vma *root = NULL;
 
        /*
         * Unlink each anon_vma chained to the VMA.  This list is ordered
         * from newest to oldest, ensuring the root anon_vma gets freed last.
         */
        list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
-               anon_vma_unlink(avc);
+               struct anon_vma *anon_vma = avc->anon_vma;
+
+               root = lock_anon_vma_root(root, anon_vma);
+               list_del(&avc->same_anon_vma);
+
+               /*
+                * Leave empty anon_vmas on the list - we'll need
+                * to free them outside the lock.
+                */
+               if (list_empty(&anon_vma->head))
+                       continue;
+
+               list_del(&avc->same_vma);
+               anon_vma_chain_free(avc);
+       }
+       unlock_anon_vma_root(root);
+
+       /*
+        * Iterate the list once more, it now only contains empty and unlinked
+        * anon_vmas, destroy them. Could not do before due to __put_anon_vma()
+        * needing to acquire the anon_vma->root->mutex.
+        */
+       list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
+               struct anon_vma *anon_vma = avc->anon_vma;
+
+               put_anon_vma(anon_vma);
+
                list_del(&avc->same_vma);
                anon_vma_chain_free(avc);
        }