ARM: OMAP3: PM: remove access to PRM_VOLTCTRL register

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

diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 35ff447..a160ec8 100644 (file)
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -20,7 +20,7 @@
 #include <linux/slab.h>
 
 /* global SRCU for all MMs */
-struct srcu_struct srcu;
+static struct srcu_struct srcu;
 
 /*
  * This function can't run concurrently against mmu_notifier_register
@@ -41,17 +41,16 @@ void __mmu_notifier_release(struct mm_struct *mm)
        int id;
 
        /*
-        * RCU here will block mmu_notifier_unregister until
+        * SRCU here will block mmu_notifier_unregister until
         * ->release returns.
         */
        id = srcu_read_lock(&srcu);
        hlist_for_each_entry_rcu(mn, n, &mm->mmu_notifier_mm->list, hlist)
                /*
-                * if ->release runs before mmu_notifier_unregister it
-                * must be handled as it's the only way for the driver
-                * to flush all existing sptes and stop the driver
-                * from establishing any more sptes before all the
-                * pages in the mm are freed.
+                * If ->release runs before mmu_notifier_unregister it must be
+                * handled, as it's the only way for the driver to flush all
+                * existing sptes and stop the driver from establishing any more
+                * sptes before all the pages in the mm are freed.
                 */
                if (mn->ops->release)
                        mn->ops->release(mn, mm);
@@ -64,22 +63,22 @@ void __mmu_notifier_release(struct mm_struct *mm)
                                 hlist);
                /*
                 * We arrived before mmu_notifier_unregister so
-                * mmu_notifier_unregister will do nothing other than
-                * to wait ->release to finish and
-                * mmu_notifier_unregister to return.
+                * mmu_notifier_unregister will do nothing other than to wait
+                * for ->release to finish and for mmu_notifier_unregister to
+                * return.
                 */
                hlist_del_init_rcu(&mn->hlist);
        }
        spin_unlock(&mm->mmu_notifier_mm->lock);
 
        /*
-        * synchronize_srcu here prevents mmu_notifier_release to
-        * return to exit_mmap (which would proceed freeing all pages
-        * in the mm) until the ->release method returns, if it was
-        * invoked by mmu_notifier_unregister.
+        * synchronize_srcu here prevents mmu_notifier_release from returning to
+        * exit_mmap (which would proceed with freeing all pages in the mm)
+        * until the ->release method returns, if it was invoked by
+        * mmu_notifier_unregister.
         *
-        * The mmu_notifier_mm can't go away from under us because one
-        * mm_count is hold by exit_mmap.
+        * The mmu_notifier_mm can't go away from under us because one mm_count
+        * is held by exit_mmap.
         */
        synchronize_srcu(&srcu);
 }
@@ -302,28 +301,31 @@ void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm)
 
        if (!hlist_unhashed(&mn->hlist)) {
                /*
-                * RCU here will force exit_mmap to wait ->release to finish
-                * before freeing the pages.
+                * SRCU here will force exit_mmap to wait for ->release to
+                * finish before freeing the pages.
                 */
                int id;
 
                id = srcu_read_lock(&srcu);
                /*
-                * exit_mmap will block in mmu_notifier_release to
-                * guarantee ->release is called before freeing the
-                * pages.
+                * exit_mmap will block in mmu_notifier_release to guarantee
+                * that ->release is called before freeing the pages.
                 */
                if (mn->ops->release)
                        mn->ops->release(mn, mm);
                srcu_read_unlock(&srcu, id);
 
                spin_lock(&mm->mmu_notifier_mm->lock);
-               hlist_del_rcu(&mn->hlist);
+               /*
+                * Can not use list_del_rcu() since __mmu_notifier_release
+                * can delete it before we hold the lock.
+                */
+               hlist_del_init_rcu(&mn->hlist);
                spin_unlock(&mm->mmu_notifier_mm->lock);
        }
 
        /*
-        * Wait any running method to finish, of course including
+        * Wait for any running method to finish, of course including
         * ->release if it was run by mmu_notifier_relase instead of us.
         */
        synchronize_srcu(&srcu);