IB/hfi1: Make the cache handler own its rb tree root

The objects which use cache handling should reference their own handler
object not the internal data structure it uses to track the nodes.

Have the "users" of the mmu notifier code pass opaque objects which can
then be properly used in the mmu callbacks depending on the owners needs.

This patch has the additional benefit that operations no longer require a
look up in a list to find the handlers.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 30 insertions, 68 deletions

diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.c b/drivers/infiniband/hw/hfi1/mmu_rb.c
index e5c5ef4cf06c..9fbcfed4d34c 100644
--- a/drivers/infiniband/hw/hfi1/mmu_rb.c
+++ b/drivers/infiniband/hw/hfi1/mmu_rb.c
@@ -53,20 +53,16 @@
 #include "trace.h"
 
 struct mmu_rb_handler {
-	struct list_head list;
 	struct mmu_notifier mn;
-	struct rb_root *root;
+	struct rb_root root;
+	void *ops_arg;
 	spinlock_t lock;        /* protect the RB tree */
 	struct mmu_rb_ops *ops;
 	struct mm_struct *mm;
 };
 
-static LIST_HEAD(mmu_rb_handlers);
-static DEFINE_SPINLOCK(mmu_rb_lock); /* protect mmu_rb_handlers list */
-
 static unsigned long mmu_node_start(struct mmu_rb_node *);
 static unsigned long mmu_node_last(struct mmu_rb_node *);
-static struct mmu_rb_handler *find_mmu_handler(struct rb_root *);
 static inline void mmu_notifier_page(struct mmu_notifier *, struct mm_struct *,
 				     unsigned long);
 static inline void mmu_notifier_range_start(struct mmu_notifier *,
@@ -96,8 +92,9 @@ static unsigned long mmu_node_last(struct mmu_rb_node *node)
 	return PAGE_ALIGN(node->addr + node->len) - 1;
 }
 
-int hfi1_mmu_rb_register(struct mm_struct *mm, struct rb_root *root,
-			 struct mmu_rb_ops *ops)
+int hfi1_mmu_rb_register(void *ops_arg, struct mm_struct *mm,
+			 struct mmu_rb_ops *ops,
+			 struct mmu_rb_handler **handler)
 {
 	struct mmu_rb_handler *handlr;
 	int ret;
@@ -106,8 +103,9 @@ int hfi1_mmu_rb_register(struct mm_struct *mm, struct rb_root *root,
 	if (!handlr)
 		return -ENOMEM;
 
-	handlr->root = root;
+	handlr->root = RB_ROOT;
 	handlr->ops = ops;
+	handlr->ops_arg = ops_arg;
 	INIT_HLIST_NODE(&handlr->mn.hlist);
 	spin_lock_init(&handlr->lock);
 	handlr->mn.ops = &mn_opts;
@@ -119,52 +117,38 @@ int hfi1_mmu_rb_register(struct mm_struct *mm, struct rb_root *root,
 		return ret;
 	}
 
-	spin_lock(&mmu_rb_lock);
-	list_add_tail_rcu(&handlr->list, &mmu_rb_handlers);
-	spin_unlock(&mmu_rb_lock);
-
-	return ret;
+	*handler = handlr;
+	return 0;
 }
 
-void hfi1_mmu_rb_unregister(struct rb_root *root)
+void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler)
 {
-	struct mmu_rb_handler *handler = find_mmu_handler(root);
 	struct mmu_rb_node *rbnode;
 	struct rb_node *node;
 	unsigned long flags;
 
-	if (!handler)
-		return;
-
 	/* Unregister first so we don't get any more notifications. */
 	mmu_notifier_unregister(&handler->mn, handler->mm);
 
-	spin_lock(&mmu_rb_lock);
-	list_del_rcu(&handler->list);
-	spin_unlock(&mmu_rb_lock);
-	synchronize_rcu();
-
 	spin_lock_irqsave(&handler->lock, flags);
-	while ((node = rb_first(root))) {
+	while ((node = rb_first(&handler->root))) {
 		rbnode = rb_entry(node, struct mmu_rb_node, node);
-		rb_erase(node, root);
-		handler->ops->remove(root, rbnode, NULL);
+		rb_erase(node, &handler->root);
+		handler->ops->remove(handler->ops_arg, rbnode,
+				     NULL);
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);
 
 	kfree(handler);
 }
 
-int hfi1_mmu_rb_insert(struct rb_root *root, struct mmu_rb_node *mnode)
+int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
+		       struct mmu_rb_node *mnode)
 {
-	struct mmu_rb_handler *handler = find_mmu_handler(root);
 	struct mmu_rb_node *node;
 	unsigned long flags;
 	int ret = 0;
 
-	if (!handler)
-		return -EINVAL;
-
 	spin_lock_irqsave(&handler->lock, flags);
 	hfi1_cdbg(MMU, "Inserting node addr 0x%llx, len %u", mnode->addr,
 		  mnode->len);
@@ -173,11 +157,11 @@ int hfi1_mmu_rb_insert(struct rb_root *root, struct mmu_rb_node *mnode)
 		ret = -EINVAL;
 		goto unlock;
 	}
-	__mmu_int_rb_insert(mnode, root);
+	__mmu_int_rb_insert(mnode, &handler->root);
 
-	ret = handler->ops->insert(root, mnode);
+	ret = handler->ops->insert(handler->ops_arg, mnode);
 	if (ret)
-		__mmu_int_rb_remove(mnode, root);
+		__mmu_int_rb_remove(mnode, &handler->root);
 unlock:
 	spin_unlock_irqrestore(&handler->lock, flags);
 	return ret;
@@ -192,10 +176,10 @@ static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 
 	hfi1_cdbg(MMU, "Searching for addr 0x%llx, len %u", addr, len);
 	if (!handler->ops->filter) {
-		node = __mmu_int_rb_iter_first(handler->root, addr,
+		node = __mmu_int_rb_iter_first(&handler->root, addr,
 					       (addr + len) - 1);
 	} else {
-		for (node = __mmu_int_rb_iter_first(handler->root, addr,
+		for (node = __mmu_int_rb_iter_first(&handler->root, addr,
 						    (addr + len) - 1);
 		     node;
 		     node = __mmu_int_rb_iter_next(node, addr,
@@ -207,56 +191,34 @@ static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 	return node;
 }
 
-struct mmu_rb_node *hfi1_mmu_rb_extract(struct rb_root *root,
+struct mmu_rb_node *hfi1_mmu_rb_extract(struct mmu_rb_handler *handler,
 					unsigned long addr, unsigned long len)
 {
-	struct mmu_rb_handler *handler = find_mmu_handler(root);
 	struct mmu_rb_node *node;
 	unsigned long flags;
 
-	if (!handler)
-		return ERR_PTR(-EINVAL);
-
 	spin_lock_irqsave(&handler->lock, flags);
 	node = __mmu_rb_search(handler, addr, len);
 	if (node)
-		__mmu_int_rb_remove(node, handler->root);
+		__mmu_int_rb_remove(node, &handler->root);
 	spin_unlock_irqrestore(&handler->lock, flags);
 
 	return node;
 }
 
-void hfi1_mmu_rb_remove(struct rb_root *root, struct mmu_rb_node *node)
+void hfi1_mmu_rb_remove(struct mmu_rb_handler *handler,
+			struct mmu_rb_node *node)
 {
 	unsigned long flags;
-	struct mmu_rb_handler *handler = find_mmu_handler(root);
-
-	if (!handler || !node)
-		return;
 
 	/* Validity of handler and node pointers has been checked by caller. */
 	hfi1_cdbg(MMU, "Removing node addr 0x%llx, len %u", node->addr,
 		  node->len);
 	spin_lock_irqsave(&handler->lock, flags);
-	__mmu_int_rb_remove(node, handler->root);
+	__mmu_int_rb_remove(node, &handler->root);
 	spin_unlock_irqrestore(&handler->lock, flags);
 
-	handler->ops->remove(handler->root, node, NULL);
-}
-
-static struct mmu_rb_handler *find_mmu_handler(struct rb_root *root)
-{
-	struct mmu_rb_handler *handler;
-
-	rcu_read_lock();
-	list_for_each_entry_rcu(handler, &mmu_rb_handlers, list) {
-		if (handler->root == root)
-			goto unlock;
-	}
-	handler = NULL;
-unlock:
-	rcu_read_unlock();
-	return handler;
+	handler->ops->remove(handler->ops_arg, node, NULL);
 }
 
 static inline void mmu_notifier_page(struct mmu_notifier *mn,
@@ -279,7 +241,7 @@ static void mmu_notifier_mem_invalidate(struct mmu_notifier *mn,
 {
 	struct mmu_rb_handler *handler =
 		container_of(mn, struct mmu_rb_handler, mn);
-	struct rb_root *root = handler->root;
+	struct rb_root *root = &handler->root;
 	struct mmu_rb_node *node, *ptr = NULL;
 	unsigned long flags;
 
@@ -290,9 +252,9 @@ static void mmu_notifier_mem_invalidate(struct mmu_notifier *mn,
 		ptr = __mmu_int_rb_iter_next(node, start, end - 1);
 		hfi1_cdbg(MMU, "Invalidating node addr 0x%llx, len %u",
 			  node->addr, node->len);
-		if (handler->ops->invalidate(root, node)) {
+		if (handler->ops->invalidate(handler->ops_arg, node)) {
 			__mmu_int_rb_remove(node, root);
-			handler->ops->remove(root, node, mm);
+			handler->ops->remove(handler->ops_arg, node, mm);
 		}
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);