kill some ida hacks

5 files changed, 34 insertions, 87 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 7b1ca9ba0b0a..001e4762b655 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -32,9 +32,6 @@
 static int event;
 static DEFINE_IDA(mnt_id_ida);
 static DEFINE_IDA(mnt_group_ida);
-static DEFINE_SPINLOCK(mnt_id_lock);
-static int mnt_id_start = 0;
-static int mnt_group_start = 1;
 
 static struct list_head *mount_hashtable __read_mostly;
 static struct list_head *mountpoint_hashtable __read_mostly;
@@ -71,29 +68,17 @@ static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
  */
 static int mnt_alloc_id(struct mount *mnt)
 {
-	int res;
-
-retry:
-	ida_pre_get(&mnt_id_ida, GFP_KERNEL);
-	spin_lock(&mnt_id_lock);
-	res = ida_get_new_above(&mnt_id_ida, mnt_id_start, &mnt->mnt_id);
-	if (!res)
-		mnt_id_start = mnt->mnt_id + 1;
-	spin_unlock(&mnt_id_lock);
-	if (res == -EAGAIN)
-		goto retry;
+	int res = ida_get(&mnt_id_ida, GFP_KERNEL);
+	if (res < 0)
+		return res;
 
-	return res;
+	mnt->mnt_id = res;
+	return 0;
 }
 
 static void mnt_free_id(struct mount *mnt)
 {
-	int id = mnt->mnt_id;
-	spin_lock(&mnt_id_lock);
-	ida_remove(&mnt_id_ida, id);
-	if (mnt_id_start > id)
-		mnt_id_start = id;
-	spin_unlock(&mnt_id_lock);
+	ida_remove(&mnt_id_ida, mnt->mnt_id);
 }
 
 /*
@@ -103,18 +88,12 @@ static void mnt_free_id(struct mount *mnt)
  */
 static int mnt_alloc_group_id(struct mount *mnt)
 {
-	int res;
-
-	if (!ida_pre_get(&mnt_group_ida, GFP_KERNEL))
-		return -ENOMEM;
-
-	res = ida_get_new_above(&mnt_group_ida,
-				mnt_group_start,
-				&mnt->mnt_group_id);
-	if (!res)
-		mnt_group_start = mnt->mnt_group_id + 1;
+	int res = ida_simple_get(&mnt_id_ida, 1, 0, GFP_KERNEL);
+	if (res < 0)
+		return res;
 
-	return res;
+	mnt->mnt_group_id = res;
+	return 0;
 }
 
 /*
@@ -122,11 +101,7 @@ static int mnt_alloc_group_id(struct mount *mnt)
  */
 void mnt_release_group_id(struct mount *mnt)
 {
-	int id = mnt->mnt_group_id;
-	ida_remove(&mnt_group_ida, id);
-	if (mnt_group_start > id)
-		mnt_group_start = id;
-	mnt->mnt_group_id = 0;
+	ida_remove(&mnt_group_ida, mnt->mnt_group_id);
 }
 
 /*
diff --git a/fs/super.c b/fs/super.c
index 7465d4364208..9c2febd1c56a 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -818,36 +818,18 @@ void emergency_remount(void)
  */
 
 static DEFINE_IDA(unnamed_dev_ida);
-static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
-static int unnamed_dev_start = 0; /* don't bother trying below it */
 
 int get_anon_bdev(dev_t *p)
 {
 	int dev;
-	int error;
 
- retry:
-	if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
-		return -ENOMEM;
-	spin_lock(&unnamed_dev_lock);
-	error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
-	if (!error)
-		unnamed_dev_start = dev + 1;
-	spin_unlock(&unnamed_dev_lock);
-	if (error == -EAGAIN)
-		/* We raced and lost with another CPU. */
-		goto retry;
-	else if (error)
-		return -EAGAIN;
-
-	if (dev == (1 << MINORBITS)) {
-		spin_lock(&unnamed_dev_lock);
-		ida_remove(&unnamed_dev_ida, dev);
-		if (unnamed_dev_start > dev)
-			unnamed_dev_start = dev;
-		spin_unlock(&unnamed_dev_lock);
+	dev = ida_simple_get(&unnamed_dev_ida, 0,
+			     1 << MINORBITS, GFP_ATOMIC);
+	if (dev == -ENOSPC)
 		return -EMFILE;
-	}
+	if (dev < 0)
+		return dev;
+
 	*p = MKDEV(0, dev & MINORMASK);
 	return 0;
 }
@@ -855,12 +837,7 @@ EXPORT_SYMBOL(get_anon_bdev);
 
 void free_anon_bdev(dev_t dev)
 {
-	int slot = MINOR(dev);
-	spin_lock(&unnamed_dev_lock);
-	ida_remove(&unnamed_dev_ida, slot);
-	if (slot < unnamed_dev_start)
-		unnamed_dev_start = slot;
-	spin_unlock(&unnamed_dev_lock);
+	ida_remove(&unnamed_dev_ida, MINOR(dev));
 }
 EXPORT_SYMBOL(free_anon_bdev);
 
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 15b0d293c6d7..1b305ac344af 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -220,7 +220,7 @@ struct ida {
 #define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)
 
 int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
-int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
+int ida_get_new(struct ida *ida, int *p_id);
 void ida_remove(struct ida *ida, unsigned id);
 void ida_destroy(struct ida *ida);
 void ida_init(struct ida *ida);
@@ -228,18 +228,6 @@ void ida_init(struct ida *ida);
 int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
 		   gfp_t gfp_mask);
 
-/**
- * ida_get_new - allocate new ID
- * @ida:	idr handle
- * @p_id:	pointer to the allocated handle
- *
- * Simple wrapper around ida_get_new_above() w/ @starting_id of zero.
- */
-static inline int ida_get_new(struct ida *ida, int *p_id)
-{
-	return ida_get_new_above(ida, 0, p_id);
-}
-
 static inline int ida_get(struct ida *ida, gfp_t gfp_mask)
 {
 	return ida_simple_get(ida, 0, 0, gfp_mask);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 139bb88efd94..3ed66110e9ee 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -190,7 +190,6 @@ static LIST_HEAD(roots);
 static int root_count;
 
 static DEFINE_IDA(hierarchy_ida);
-static int next_hierarchy_id;
 
 /* dummytop is a shorthand for the dummy hierarchy's top cgroup */
 #define dummytop (&rootnode.top_cgroup)
@@ -1427,15 +1426,11 @@ static void init_cgroup_root(struct cgroupfs_root *root)
 
 static bool init_root_id(struct cgroupfs_root *root)
 {
-	int ret = 0;
-
-	ret = ida_simple_get(&hierarchy_ida, next_hierarchy_id, 0, GFP_KERNEL);
+	int ret = ida_get(&hierarchy_ida, GFP_KERNEL);
 	if (ret < 0)
 		return false;
 
 	root->hierarchy_id = ret;
-	next_hierarchy_id = root->hierarchy_id + 1;
-
 	return true;
 }
 
diff --git a/lib/idr.c b/lib/idr.c
index b4e95f793c9f..c61418a83f68 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -1019,7 +1019,19 @@ int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
 
 	return 0;
 }
-EXPORT_SYMBOL(ida_get_new_above);
+
+/**
+ * ida_get_new - allocate new ID
+ * @ida:	idr handle
+ * @p_id:	pointer to the allocated handle
+ *
+ * Simple wrapper around ida_get_new_above() w/ @starting_id of zero.
+ */
+int ida_get_new(struct ida *ida, int *p_id)
+{
+	return ida_get_new_above(ida, 0, p_id);
+}
+EXPORT_SYMBOL(ida_get_new);
 
 static void __ida_remove(struct ida *ida, int id)
 {