Merge branch 'xarray' of git://git.infradead.org/users/willy/linux-dax

Pull XArray conversion from Matthew Wilcox:
 "The XArray provides an improved interface to the radix tree data
  structure, providing locking as part of the API, specifying GFP flags
  at allocation time, eliminating preloading, less re-walking the tree,
  more efficient iterations and not exposing RCU-protected pointers to
  its users.

  This patch set

   1. Introduces the XArray implementation

   2. Converts the pagecache to use it

   3. Converts memremap to use it

  The page cache is the most complex and important user of the radix
  tree, so converting it was most important. Converting the memremap
  code removes the only other user of the multiorder code, which allows
  us to remove the radix tree code that supported it.

  I have 40+ followup patches to convert many other users of the radix
  tree over to the XArray, but I'd like to get this part in first. The
  other conversions haven't been in linux-next and aren't suitable for
  applying yet, but you can see them in the xarray-conv branch if you're
  interested"

* 'xarray' of git://git.infradead.org/users/willy/linux-dax: (90 commits)
  radix tree: Remove multiorder support
  radix tree test: Convert multiorder tests to XArray
  radix tree tests: Convert item_delete_rcu to XArray
  radix tree tests: Convert item_kill_tree to XArray
  radix tree tests: Move item_insert_order
  radix tree test suite: Remove multiorder benchmarking
  radix tree test suite: Remove __item_insert
  memremap: Convert to XArray
  xarray: Add range store functionality
  xarray: Move multiorder_check to in-kernel tests
  xarray: Move multiorder_shrink to kernel tests
  xarray: Move multiorder account test in-kernel
  radix tree test suite: Convert iteration test to XArray
  radix tree test suite: Convert tag_tagged_items to XArray
  radix tree: Remove radix_tree_clear_tags
  radix tree: Remove radix_tree_maybe_preload_order
  radix tree: Remove split/join code
  radix tree: Remove radix_tree_update_node_t
  page cache: Finish XArray conversion
  dax: Convert page fault handlers to XArray
  ...

1 files changed, 53 insertions, 56 deletions

diff --git a/tools/testing/radix-tree/iteration_check.c b/tools/testing/radix-tree/iteration_check.c
index a92bab513701..238db187aa15 100644
--- a/tools/testing/radix-tree/iteration_check.c
+++ b/tools/testing/radix-tree/iteration_check.c
@@ -1,5 +1,5 @@
 /*
- * iteration_check.c: test races having to do with radix tree iteration
+ * iteration_check.c: test races having to do with xarray iteration
  * Copyright (c) 2016 Intel Corporation
  * Author: Ross Zwisler <ross.zwisler@linux.intel.com>
  *
@@ -12,41 +12,54 @@
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  */
-#include <linux/radix-tree.h>
 #include <pthread.h>
 #include "test.h"
 
 #define NUM_THREADS	5
 #define MAX_IDX		100
-#define TAG		0
-#define NEW_TAG		1
+#define TAG		XA_MARK_0
+#define NEW_TAG		XA_MARK_1
 
-static pthread_mutex_t tree_lock = PTHREAD_MUTEX_INITIALIZER;
 static pthread_t threads[NUM_THREADS];
 static unsigned int seeds[3];
-static RADIX_TREE(tree, GFP_KERNEL);
+static DEFINE_XARRAY(array);
 static bool test_complete;
 static int max_order;
 
-/* relentlessly fill the tree with tagged entries */
+void my_item_insert(struct xarray *xa, unsigned long index)
+{
+	XA_STATE(xas, xa, index);
+	struct item *item = item_create(index, 0);
+	int order;
+
+retry:
+	xas_lock(&xas);
+	for (order = max_order; order >= 0; order--) {
+		xas_set_order(&xas, index, order);
+		item->order = order;
+		if (xas_find_conflict(&xas))
+			continue;
+		xas_store(&xas, item);
+		xas_set_mark(&xas, TAG);
+		break;
+	}
+	xas_unlock(&xas);
+	if (xas_nomem(&xas, GFP_KERNEL))
+		goto retry;
+	if (order < 0)
+		free(item);
+}
+
+/* relentlessly fill the array with tagged entries */
 static void *add_entries_fn(void *arg)
 {
 	rcu_register_thread();
 
 	while (!test_complete) {
 		unsigned long pgoff;
-		int order;
 
 		for (pgoff = 0; pgoff < MAX_IDX; pgoff++) {
-			pthread_mutex_lock(&tree_lock);
-			for (order = max_order; order >= 0; order--) {
-				if (item_insert_order(&tree, pgoff, order)
-						== 0) {
-					item_tag_set(&tree, pgoff, TAG);
-					break;
-				}
-			}
-			pthread_mutex_unlock(&tree_lock);
+			my_item_insert(&array, pgoff);
 		}
 	}
 
@@ -56,33 +69,25 @@ static void *add_entries_fn(void *arg)
 }
 
 /*
- * Iterate over the tagged entries, doing a radix_tree_iter_retry() as we find
- * things that have been removed and randomly resetting our iteration to the
- * next chunk with radix_tree_iter_resume().  Both radix_tree_iter_retry() and
- * radix_tree_iter_resume() cause radix_tree_next_slot() to be called with a
- * NULL 'slot' variable.
+ * Iterate over tagged entries, retrying when we find ourselves in a deleted
+ * node and randomly pausing the iteration.
  */
 static void *tagged_iteration_fn(void *arg)
 {
-	struct radix_tree_iter iter;
-	void **slot;
+	XA_STATE(xas, &array, 0);
+	void *entry;
 
 	rcu_register_thread();
 
 	while (!test_complete) {
+		xas_set(&xas, 0);
 		rcu_read_lock();
-		radix_tree_for_each_tagged(slot, &tree, &iter, 0, TAG) {
-			void *entry = radix_tree_deref_slot(slot);
-			if (unlikely(!entry))
+		xas_for_each_marked(&xas, entry, ULONG_MAX, TAG) {
+			if (xas_retry(&xas, entry))
 				continue;
 
-			if (radix_tree_deref_retry(entry)) {
-				slot = radix_tree_iter_retry(&iter);
-				continue;
-			}
-
 			if (rand_r(&seeds[0]) % 50 == 0) {
-				slot = radix_tree_iter_resume(slot, &iter);
+				xas_pause(&xas);
 				rcu_read_unlock();
 				rcu_barrier();
 				rcu_read_lock();
@@ -97,33 +102,25 @@ static void *tagged_iteration_fn(void *arg)
 }
 
 /*
- * Iterate over the entries, doing a radix_tree_iter_retry() as we find things
- * that have been removed and randomly resetting our iteration to the next
- * chunk with radix_tree_iter_resume().  Both radix_tree_iter_retry() and
- * radix_tree_iter_resume() cause radix_tree_next_slot() to be called with a
- * NULL 'slot' variable.
+ * Iterate over the entries, retrying when we find ourselves in a deleted
+ * node and randomly pausing the iteration.
  */
 static void *untagged_iteration_fn(void *arg)
 {
-	struct radix_tree_iter iter;
-	void **slot;
+	XA_STATE(xas, &array, 0);
+	void *entry;
 
 	rcu_register_thread();
 
 	while (!test_complete) {
+		xas_set(&xas, 0);
 		rcu_read_lock();
-		radix_tree_for_each_slot(slot, &tree, &iter, 0) {
-			void *entry = radix_tree_deref_slot(slot);
-			if (unlikely(!entry))
+		xas_for_each(&xas, entry, ULONG_MAX) {
+			if (xas_retry(&xas, entry))
 				continue;
 
-			if (radix_tree_deref_retry(entry)) {
-				slot = radix_tree_iter_retry(&iter);
-				continue;
-			}
-
 			if (rand_r(&seeds[1]) % 50 == 0) {
-				slot = radix_tree_iter_resume(slot, &iter);
+				xas_pause(&xas);
 				rcu_read_unlock();
 				rcu_barrier();
 				rcu_read_lock();
@@ -138,7 +135,7 @@ static void *untagged_iteration_fn(void *arg)
 }
 
 /*
- * Randomly remove entries to help induce radix_tree_iter_retry() calls in the
+ * Randomly remove entries to help induce retries in the
  * two iteration functions.
  */
 static void *remove_entries_fn(void *arg)
@@ -147,12 +144,13 @@ static void *remove_entries_fn(void *arg)
 
 	while (!test_complete) {
 		int pgoff;
+		struct item *item;
 
 		pgoff = rand_r(&seeds[2]) % MAX_IDX;
 
-		pthread_mutex_lock(&tree_lock);
-		item_delete(&tree, pgoff);
-		pthread_mutex_unlock(&tree_lock);
+		item = xa_erase(&array, pgoff);
+		if (item)
+			item_free(item, pgoff);
 	}
 
 	rcu_unregister_thread();
@@ -165,8 +163,7 @@ static void *tag_entries_fn(void *arg)
 	rcu_register_thread();
 
 	while (!test_complete) {
-		tag_tagged_items(&tree, &tree_lock, 0, MAX_IDX, 10, TAG,
-					NEW_TAG);
+		tag_tagged_items(&array, 0, MAX_IDX, 10, TAG, NEW_TAG);
 	}
 	rcu_unregister_thread();
 	return NULL;
@@ -217,5 +214,5 @@ void iteration_test(unsigned order, unsigned test_duration)
 		}
 	}
 
-	item_kill_tree(&tree);
+	item_kill_tree(&array);
 }