1 files changed, 120 insertions, 161 deletions

diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.c b/drivers/infiniband/hw/hfi1/mmu_rb.c
index 24ca17b77b72..67a5c410fb5e 100644
--- a/drivers/infiniband/hw/hfi1/mmu_rb.c
+++ b/drivers/infiniband/hw/hfi1/mmu_rb.c
@@ -1,78 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
+ * Copyright(c) 2020 Cornelis Networks, Inc.
  * Copyright(c) 2016 - 2017 Intel Corporation.
- *
- * This file is provided under a dual BSD/GPLv2 license.  When using or
- * redistributing this file, you may do so under either license.
- *
- * GPL LICENSE SUMMARY
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * BSD LICENSE
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- *  - Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  - Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *  - Neither the name of Intel Corporation nor the names of its
- *    contributors may be used to endorse or promote products derived
- *    from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
  */
+
 #include <linux/list.h>
 #include <linux/rculist.h>
 #include <linux/mmu_notifier.h>
 #include <linux/interval_tree_generic.h>
+#include <linux/sched/mm.h>
 
 #include "mmu_rb.h"
 #include "trace.h"
 
-struct mmu_rb_handler {
-	struct mmu_notifier mn;
-	struct rb_root_cached root;
-	void *ops_arg;
-	spinlock_t lock;        /* protect the RB tree */
-	struct mmu_rb_ops *ops;
-	struct mm_struct *mm;
-	struct list_head lru_list;
-	struct work_struct del_work;
-	struct list_head del_list;
-	struct workqueue_struct *wq;
-};
-
 static unsigned long mmu_node_start(struct mmu_rb_node *);
 static unsigned long mmu_node_last(struct mmu_rb_node *);
 static int mmu_notifier_range_start(struct mmu_notifier *,
 		const struct mmu_notifier_range *);
 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *,
 					   unsigned long, unsigned long);
-static void do_remove(struct mmu_rb_handler *handler,
-		      struct list_head *del_list);
+static void release_immediate(struct kref *refcount);
 static void handle_remove(struct work_struct *work);
 
 static const struct mmu_notifier_ops mn_opts = {
@@ -92,37 +39,39 @@ static unsigned long mmu_node_last(struct mmu_rb_node *node)
 	return PAGE_ALIGN(node->addr + node->len) - 1;
 }
 
-int hfi1_mmu_rb_register(void *ops_arg, struct mm_struct *mm,
-			 struct mmu_rb_ops *ops,
+int hfi1_mmu_rb_register(void *ops_arg,
+			 const struct mmu_rb_ops *ops,
 			 struct workqueue_struct *wq,
 			 struct mmu_rb_handler **handler)
 {
-	struct mmu_rb_handler *handlr;
+	struct mmu_rb_handler *h;
+	void *free_ptr;
 	int ret;
 
-	handlr = kmalloc(sizeof(*handlr), GFP_KERNEL);
-	if (!handlr)
+	free_ptr = kzalloc(sizeof(*h) + cache_line_size() - 1, GFP_KERNEL);
+	if (!free_ptr)
 		return -ENOMEM;
 
-	handlr->root = RB_ROOT_CACHED;
-	handlr->ops = ops;
-	handlr->ops_arg = ops_arg;
-	INIT_HLIST_NODE(&handlr->mn.hlist);
-	spin_lock_init(&handlr->lock);
-	handlr->mn.ops = &mn_opts;
-	handlr->mm = mm;
-	INIT_WORK(&handlr->del_work, handle_remove);
-	INIT_LIST_HEAD(&handlr->del_list);
-	INIT_LIST_HEAD(&handlr->lru_list);
-	handlr->wq = wq;
-
-	ret = mmu_notifier_register(&handlr->mn, handlr->mm);
+	h = PTR_ALIGN(free_ptr, cache_line_size());
+	h->root = RB_ROOT_CACHED;
+	h->ops = ops;
+	h->ops_arg = ops_arg;
+	INIT_HLIST_NODE(&h->mn.hlist);
+	spin_lock_init(&h->lock);
+	h->mn.ops = &mn_opts;
+	INIT_WORK(&h->del_work, handle_remove);
+	INIT_LIST_HEAD(&h->del_list);
+	INIT_LIST_HEAD(&h->lru_list);
+	h->wq = wq;
+	h->free_ptr = free_ptr;
+
+	ret = mmu_notifier_register(&h->mn, current->mm);
 	if (ret) {
-		kfree(handlr);
+		kfree(free_ptr);
 		return ret;
 	}
 
-	*handler = handlr;
+	*handler = h;
 	return 0;
 }
 
@@ -133,8 +82,11 @@ void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler)
 	unsigned long flags;
 	struct list_head del_list;
 
+	/* Prevent freeing of mm until we are completely finished. */
+	mmgrab(handler->mn.mm);
+
 	/* Unregister first so we don't get any more notifications. */
-	mmu_notifier_unregister(&handler->mn, handler->mm);
+	mmu_notifier_unregister(&handler->mn, handler->mn.mm);
 
 	/*
 	 * Make sure the wq delete handler is finished running.  It will not
@@ -153,9 +105,16 @@ void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler)
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);
 
-	do_remove(handler, &del_list);
+	while (!list_empty(&del_list)) {
+		rbnode = list_first_entry(&del_list, struct mmu_rb_node, list);
+		list_del(&rbnode->list);
+		kref_put(&rbnode->refcount, release_immediate);
+	}
+
+	/* Now the mm may be freed. */
+	mmdrop(handler->mn.mm);
 
-	kfree(handler);
+	kfree(handler->free_ptr);
 }
 
 int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
@@ -165,27 +124,39 @@ int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
 	unsigned long flags;
 	int ret = 0;
 
-	trace_hfi1_mmu_rb_insert(mnode->addr, mnode->len);
+	trace_hfi1_mmu_rb_insert(mnode);
+
+	if (current->mm != handler->mn.mm)
+		return -EPERM;
+
 	spin_lock_irqsave(&handler->lock, flags);
 	node = __mmu_rb_search(handler, mnode->addr, mnode->len);
 	if (node) {
-		ret = -EINVAL;
+		ret = -EEXIST;
 		goto unlock;
 	}
 	__mmu_int_rb_insert(mnode, &handler->root);
-	list_add(&mnode->list, &handler->lru_list);
-
-	ret = handler->ops->insert(handler->ops_arg, mnode);
-	if (ret) {
-		__mmu_int_rb_remove(mnode, &handler->root);
-		list_del(&mnode->list); /* remove from LRU list */
-	}
+	list_add_tail(&mnode->list, &handler->lru_list);
+	mnode->handler = handler;
 unlock:
 	spin_unlock_irqrestore(&handler->lock, flags);
 	return ret;
 }
 
 /* Caller must hold handler lock */
+struct mmu_rb_node *hfi1_mmu_rb_get_first(struct mmu_rb_handler *handler,
+					  unsigned long addr, unsigned long len)
+{
+	struct mmu_rb_node *node;
+
+	trace_hfi1_mmu_rb_search(addr, len);
+	node = __mmu_int_rb_iter_first(&handler->root, addr, (addr + len) - 1);
+	if (node)
+		list_move_tail(&node->list, &handler->lru_list);
+	return node;
+}
+
+/* Caller must hold handler lock */
 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 					   unsigned long addr,
 					   unsigned long len)
@@ -209,27 +180,47 @@ static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 	return node;
 }
 
-bool hfi1_mmu_rb_remove_unless_exact(struct mmu_rb_handler *handler,
-				     unsigned long addr, unsigned long len,
-				     struct mmu_rb_node **rb_node)
+/*
+ * Must NOT call while holding mnode->handler->lock.
+ * mnode->handler->ops->remove() may sleep and mnode->handler->lock is a
+ * spinlock.
+ */
+static void release_immediate(struct kref *refcount)
 {
-	struct mmu_rb_node *node;
+	struct mmu_rb_node *mnode =
+		container_of(refcount, struct mmu_rb_node, refcount);
+	trace_hfi1_mmu_release_node(mnode);
+	mnode->handler->ops->remove(mnode->handler->ops_arg, mnode);
+}
+
+/* Caller must hold mnode->handler->lock */
+static void release_nolock(struct kref *refcount)
+{
+	struct mmu_rb_node *mnode =
+		container_of(refcount, struct mmu_rb_node, refcount);
+	list_move(&mnode->list, &mnode->handler->del_list);
+	queue_work(mnode->handler->wq, &mnode->handler->del_work);
+}
+
+/*
+ * struct mmu_rb_node->refcount kref_put() callback.
+ * Adds mmu_rb_node to mmu_rb_node->handler->del_list and queues
+ * handler->del_work on handler->wq.
+ * Does not remove mmu_rb_node from handler->lru_list or handler->rb_root.
+ * Acquires mmu_rb_node->handler->lock; do not call while already holding
+ * handler->lock.
+ */
+void hfi1_mmu_rb_release(struct kref *refcount)
+{
+	struct mmu_rb_node *mnode =
+		container_of(refcount, struct mmu_rb_node, refcount);
+	struct mmu_rb_handler *handler = mnode->handler;
 	unsigned long flags;
-	bool ret = false;
 
 	spin_lock_irqsave(&handler->lock, flags);
-	node = __mmu_rb_search(handler, addr, len);
-	if (node) {
-		if (node->addr == addr && node->len == len)
-			goto unlock;
-		__mmu_int_rb_remove(node, &handler->root);
-		list_del(&node->list); /* remove from LRU list */
-		ret = true;
-	}
-unlock:
+	list_move(&mnode->list, &mnode->handler->del_list);
 	spin_unlock_irqrestore(&handler->lock, flags);
-	*rb_node = node;
-	return ret;
+	queue_work(handler->wq, &handler->del_work);
 }
 
 void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg)
@@ -239,11 +230,17 @@ void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg)
 	unsigned long flags;
 	bool stop = false;
 
+	if (current->mm != handler->mn.mm)
+		return;
+
 	INIT_LIST_HEAD(&del_list);
 
 	spin_lock_irqsave(&handler->lock, flags);
-	list_for_each_entry_safe_reverse(rbnode, ptr, &handler->lru_list,
-					 list) {
+	list_for_each_entry_safe(rbnode, ptr, &handler->lru_list, list) {
+		/* refcount == 1 implies mmu_rb_handler has only rbnode ref */
+		if (kref_read(&rbnode->refcount) > 1)
+			continue;
+
 		if (handler->ops->evict(handler->ops_arg, rbnode, evict_arg,
 					&stop)) {
 			__mmu_int_rb_remove(rbnode, &handler->root);
@@ -255,33 +252,12 @@ void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg)
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);
 
-	while (!list_empty(&del_list)) {
-		rbnode = list_first_entry(&del_list, struct mmu_rb_node, list);
-		list_del(&rbnode->list);
-		handler->ops->remove(handler->ops_arg, rbnode);
+	list_for_each_entry_safe(rbnode, ptr, &del_list, list) {
+		trace_hfi1_mmu_rb_evict(rbnode);
+		kref_put(&rbnode->refcount, release_immediate);
 	}
 }
 
-/*
- * It is up to the caller to ensure that this function does not race with the
- * mmu invalidate notifier which may be calling the users remove callback on
- * 'node'.
- */
-void hfi1_mmu_rb_remove(struct mmu_rb_handler *handler,
-			struct mmu_rb_node *node)
-{
-	unsigned long flags;
-
-	/* Validity of handler and node pointers has been checked by caller. */
-	trace_hfi1_mmu_rb_remove(node->addr, node->len);
-	spin_lock_irqsave(&handler->lock, flags);
-	__mmu_int_rb_remove(node, &handler->root);
-	list_del(&node->list); /* remove from LRU list */
-	spin_unlock_irqrestore(&handler->lock, flags);
-
-	handler->ops->remove(handler->ops_arg, node);
-}
-
 static int mmu_notifier_range_start(struct mmu_notifier *mn,
 		const struct mmu_notifier_range *range)
 {
@@ -290,7 +266,6 @@ static int mmu_notifier_range_start(struct mmu_notifier *mn,
 	struct rb_root_cached *root = &handler->root;
 	struct mmu_rb_node *node, *ptr = NULL;
 	unsigned long flags;
-	bool added = false;
 
 	spin_lock_irqsave(&handler->lock, flags);
 	for (node = __mmu_int_rb_iter_first(root, range->start, range->end-1);
@@ -298,40 +273,18 @@ static int mmu_notifier_range_start(struct mmu_notifier *mn,
 		/* Guard against node removal. */
 		ptr = __mmu_int_rb_iter_next(node, range->start,
 					     range->end - 1);
-		trace_hfi1_mmu_mem_invalidate(node->addr, node->len);
-		if (handler->ops->invalidate(handler->ops_arg, node)) {
-			__mmu_int_rb_remove(node, root);
-			/* move from LRU list to delete list */
-			list_move(&node->list, &handler->del_list);
-			added = true;
-		}
+		trace_hfi1_mmu_mem_invalidate(node);
+		/* Remove from rb tree and lru_list. */
+		__mmu_int_rb_remove(node, root);
+		list_del_init(&node->list);
+		kref_put(&node->refcount, release_nolock);
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);
 
-	if (added)
-		queue_work(handler->wq, &handler->del_work);
-
 	return 0;
 }
 
 /*
- * Call the remove function for the given handler and the list.  This
- * is expected to be called with a delete list extracted from handler.
- * The caller should not be holding the handler lock.
- */
-static void do_remove(struct mmu_rb_handler *handler,
-		      struct list_head *del_list)
-{
-	struct mmu_rb_node *node;
-
-	while (!list_empty(del_list)) {
-		node = list_first_entry(del_list, struct mmu_rb_node, list);
-		list_del(&node->list);
-		handler->ops->remove(handler->ops_arg, node);
-	}
-}
-
-/*
  * Work queue function to remove all nodes that have been queued up to
  * be removed.  The key feature is that mm->mmap_lock is not being held
  * and the remove callback can sleep while taking it, if needed.
@@ -343,11 +296,17 @@ static void handle_remove(struct work_struct *work)
 						del_work);
 	struct list_head del_list;
 	unsigned long flags;
+	struct mmu_rb_node *node;
 
 	/* remove anything that is queued to get removed */
 	spin_lock_irqsave(&handler->lock, flags);
 	list_replace_init(&handler->del_list, &del_list);
 	spin_unlock_irqrestore(&handler->lock, flags);
 
-	do_remove(handler, &del_list);
+	while (!list_empty(&del_list)) {
+		node = list_first_entry(&del_list, struct mmu_rb_node, list);
+		list_del(&node->list);
+		trace_hfi1_mmu_release_node(node);
+		handler->ops->remove(handler->ops_arg, node);
+	}
 }