XArray updates for 5.9

- Fix the test suite after introduction of the local_lock
  - Fix a bug in the IDA spotted by Coverity
  - Change the API that allows the workingset code to delete a node
  - Fix xas_reload() when dealing with entries that occupy multiple indices
  - Add a few more tests to the test suite
  - Fix an unsigned int being shifted into an unsigned long
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Merge tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray

Pull XArray updates from Matthew Wilcox:

 - Fix the test suite after introduction of the local_lock

 - Fix a bug in the IDA spotted by Coverity

 - Change the API that allows the workingset code to delete a node

 - Fix xas_reload() when dealing with entries that occupy multiple
   indices

 - Add a few more tests to the test suite

 - Fix an unsigned int being shifted into an unsigned long

* tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray:
  XArray: Fix xas_create_range for ranges above 4 billion
  radix-tree: fix the comment of radix_tree_next_slot()
  XArray: Fix xas_reload for multi-index entries
  XArray: Add private interface for workingset node deletion
  XArray: Fix xas_for_each_conflict documentation
  XArray: Test marked multiorder iterations
  XArray: Test two more things about xa_cmpxchg
  ida: Free allocated bitmap in error path
  radix tree test suite: Fix compilation

include/linux/radix-tree.h

@@ -11,6 +11,7 @@
 #include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
+#include <linux/percpu.h>
 #include <linux/preempt.h>
 #include <linux/rcupdate.h>
 #include <linux/spinlock.h>
@@ -376,7 +377,7 @@ radix_tree_chunk_size(struct radix_tree_iter *iter)
  * radix_tree_next_slot - find next slot in chunk
  *
  * @slot:	pointer to current slot
- * @iter:	pointer to interator state
+ * @iter:	pointer to iterator state
  * @flags:	RADIX_TREE_ITER_*, should be constant
  * Returns:	pointer to next slot, or NULL if there no more left
  *

include/linux/xarray.h

@@ -1286,6 +1286,8 @@ static inline bool xa_is_advanced(const void *entry)
  */
 typedef void (*xa_update_node_t)(struct xa_node *node);
 
+void xa_delete_node(struct xa_node *, xa_update_node_t);
+
 /*
  * The xa_state is opaque to its users.  It contains various different pieces
  * of state involved in the current operation on the XArray.  It should be
@@ -1544,10 +1546,21 @@ static inline void xas_split_alloc(struct xa_state *xas, void *entry,
 static inline void *xas_reload(struct xa_state *xas)
 {
 	struct xa_node *node = xas->xa_node;
+	void *entry;
+	char offset;
 
-	if (node)
-		return xa_entry(xas->xa, node, xas->xa_offset);
-	return xa_head(xas->xa);
+	if (!node)
+		return xa_head(xas->xa);
+	if (IS_ENABLED(CONFIG_XARRAY_MULTI)) {
+		offset = (xas->xa_index >> node->shift) & XA_CHUNK_MASK;
+		entry = xa_entry(xas->xa, node, offset);
+		if (!xa_is_sibling(entry))
+			return entry;
+		offset = xa_to_sibling(entry);
+	} else {
+		offset = xas->xa_offset;
+	}
+	return xa_entry(xas->xa, node, offset);
 }
 
 /**
@@ -1736,13 +1749,12 @@ enum {
  * @xas: XArray operation state.
  * @entry: Entry retrieved from the array.
  *
- * The loop body will be executed for each entry in the XArray that lies
- * within the range specified by @xas.  If the loop completes successfully,
- * any entries that lie in this range will be replaced by @entry.  The caller
- * may break out of the loop; if they do so, the contents of the XArray will
- * be unchanged.  The operation may fail due to an out of memory condition.
- * The caller may also call xa_set_err() to exit the loop while setting an
- * error to record the reason.
+ * The loop body will be executed for each entry in the XArray that
+ * lies within the range specified by @xas.  If the loop terminates
+ * normally, @entry will be %NULL.  The user may break out of the loop,
+ * which will leave @entry set to the conflicting entry.  The caller
+ * may also call xa_set_err() to exit the loop while setting an error
+ * to record the reason.
  */
 #define xas_for_each_conflict(xas, entry) \
 	while ((entry = xas_find_conflict(xas)))

lib/idr.c

@@ -471,6 +471,7 @@ int ida_alloc_range(struct ida *ida, unsigned int min, unsigned int max,
 	goto retry;
 nospc:
 	xas_unlock_irqrestore(&xas, flags);
+	kfree(alloc);
 	return -ENOSPC;
 }
 EXPORT_SYMBOL(ida_alloc_range);

lib/radix-tree.c

@@ -20,7 +20,6 @@
 #include <linux/kernel.h>
 #include <linux/kmemleak.h>
 #include <linux/percpu.h>
-#include <linux/local_lock.h>
 #include <linux/preempt.h>		/* in_interrupt() */
 #include <linux/radix-tree.h>
 #include <linux/rcupdate.h>

lib/test_xarray.c

@@ -289,6 +289,27 @@ static noinline void check_xa_mark_2(struct xarray *xa)
 	xa_destroy(xa);
 }
 
+static noinline void check_xa_mark_3(struct xarray *xa)
+{
+#ifdef CONFIG_XARRAY_MULTI
+	XA_STATE(xas, xa, 0x41);
+	void *entry;
+	int count = 0;
+
+	xa_store_order(xa, 0x40, 2, xa_mk_index(0x40), GFP_KERNEL);
+	xa_set_mark(xa, 0x41, XA_MARK_0);
+
+	rcu_read_lock();
+	xas_for_each_marked(&xas, entry, ULONG_MAX, XA_MARK_0) {
+		count++;
+		XA_BUG_ON(xa, entry != xa_mk_index(0x40));
+	}
+	XA_BUG_ON(xa, count != 1);
+	rcu_read_unlock();
+	xa_destroy(xa);
+#endif
+}
+
 static noinline void check_xa_mark(struct xarray *xa)
 {
 	unsigned long index;
@@ -297,6 +318,7 @@ static noinline void check_xa_mark(struct xarray *xa)
 		check_xa_mark_1(xa, index);
 
 	check_xa_mark_2(xa);
+	check_xa_mark_3(xa);
 }
 
 static noinline void check_xa_shrink(struct xarray *xa)
@@ -393,6 +415,9 @@ static noinline void check_cmpxchg(struct xarray *xa)
 	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, FIVE, LOTS, GFP_KERNEL) != FIVE);
 	XA_BUG_ON(xa, xa_cmpxchg(xa, 5, FIVE, NULL, GFP_KERNEL) != NULL);
 	XA_BUG_ON(xa, xa_cmpxchg(xa, 5, NULL, FIVE, GFP_KERNEL) != NULL);
+	XA_BUG_ON(xa, xa_insert(xa, 5, FIVE, GFP_KERNEL) != -EBUSY);
+	XA_BUG_ON(xa, xa_cmpxchg(xa, 5, FIVE, NULL, GFP_KERNEL) != FIVE);
+	XA_BUG_ON(xa, xa_insert(xa, 5, FIVE, GFP_KERNEL) == -EBUSY);
 	xa_erase_index(xa, 12345678);
 	xa_erase_index(xa, 5);
 	XA_BUG_ON(xa, !xa_empty(xa));
@@ -1618,14 +1643,9 @@ static noinline void shadow_remove(struct xarray *xa)
 	xa_lock(xa);
 	while ((node = list_first_entry_or_null(&shadow_nodes,
 					struct xa_node, private_list))) {
-		XA_STATE(xas, node->array, 0);
 		XA_BUG_ON(xa, node->array != xa);
 		list_del_init(&node->private_list);
-		xas.xa_node = xa_parent_locked(node->array, node);
-		xas.xa_offset = node->offset;
-		xas.xa_shift = node->shift + XA_CHUNK_SHIFT;
-		xas_set_update(&xas, test_update_node);
-		xas_store(&xas, NULL);
+		xa_delete_node(node, test_update_node);
 	}
 	xa_unlock(xa);
 }

lib/xarray.c

@@ -706,7 +706,7 @@ void xas_create_range(struct xa_state *xas)
 	unsigned char shift = xas->xa_shift;
 	unsigned char sibs = xas->xa_sibs;
 
-	xas->xa_index |= ((sibs + 1) << shift) - 1;
+	xas->xa_index |= ((sibs + 1UL) << shift) - 1;
 	if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift)
 		xas->xa_offset |= sibs;
 	xas->xa_shift = 0;
@@ -2163,6 +2163,29 @@ unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start,
 }
 EXPORT_SYMBOL(xa_extract);
 
+/**
+ * xa_delete_node() - Private interface for workingset code.
+ * @node: Node to be removed from the tree.
+ * @update: Function to call to update ancestor nodes.
+ *
+ * Context: xa_lock must be held on entry and will not be released.
+ */
+void xa_delete_node(struct xa_node *node, xa_update_node_t update)
+{
+	struct xa_state xas = {
+		.xa = node->array,
+		.xa_index = (unsigned long)node->offset <<
+				(node->shift + XA_CHUNK_SHIFT),
+		.xa_shift = node->shift + XA_CHUNK_SHIFT,
+		.xa_offset = node->offset,
+		.xa_node = xa_parent_locked(node->array, node),
+		.xa_update = update,
+	};
+
+	xas_store(&xas, NULL);
+}
+EXPORT_SYMBOL_GPL(xa_delete_node);	/* For the benefit of the test suite */
+
 /**
  * xa_destroy() - Free all internal data structures.
  * @xa: XArray.

mm/workingset.c

@@ -519,12 +519,11 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 					  void *arg) __must_hold(lru_lock)
 {
 	struct xa_node *node = container_of(item, struct xa_node, private_list);
-	XA_STATE(xas, node->array, 0);
 	struct address_space *mapping;
 	int ret;
 
 	/*
-	 * Page cache insertions and deletions synchroneously maintain
+	 * Page cache insertions and deletions synchronously maintain
 	 * the shadow node LRU under the i_pages lock and the
 	 * lru_lock.  Because the page cache tree is emptied before
 	 * the inode can be destroyed, holding the lru_lock pins any
@@ -559,15 +558,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 	if (WARN_ON_ONCE(node->count != node->nr_values))
 		goto out_invalid;
 	mapping->nrexceptional -= node->nr_values;
-	xas.xa_node = xa_parent_locked(&mapping->i_pages, node);
-	xas.xa_offset = node->offset;
-	xas.xa_shift = node->shift + XA_CHUNK_SHIFT;
-	xas_set_update(&xas, workingset_update_node);
-	/*
-	 * We could store a shadow entry here which was the minimum of the
-	 * shadow entries we were tracking ...
-	 */
-	xas_store(&xas, NULL);
+	xa_delete_node(node, workingset_update_node);
 	__inc_lruvec_slab_state(node, WORKINGSET_NODERECLAIM);
 
 out_invalid:

tools/testing/radix-tree/idr-test.c

@@ -523,8 +523,27 @@ static void *ida_random_fn(void *arg)
 	return NULL;
 }
 
+static void *ida_leak_fn(void *arg)
+{
+	struct ida *ida = arg;
+	time_t s = time(NULL);
+	int i, ret;
+
+	rcu_register_thread();
+
+	do for (i = 0; i < 1000; i++) {
+		ret = ida_alloc_range(ida, 128, 128, GFP_KERNEL);
+		if (ret >= 0)
+			ida_free(ida, 128);
+	} while (time(NULL) < s + 2);
+
+	rcu_unregister_thread();
+	return NULL;
+}
+
 void ida_thread_tests(void)
 {
+	DEFINE_IDA(ida);
 	pthread_t threads[20];
 	int i;
 
@@ -536,6 +555,16 @@ void ida_thread_tests(void)
 
 	while (i--)
 		pthread_join(threads[i], NULL);
+
+	for (i = 0; i < ARRAY_SIZE(threads); i++)
+		if (pthread_create(&threads[i], NULL, ida_leak_fn, &ida)) {
+			perror("creating ida thread");
+			exit(1);
+		}
+
+	while (i--)
+		pthread_join(threads[i], NULL);
+	assert(ida_is_empty(&ida));
 }
 
 void ida_tests(void)

tools/testing/radix-tree/linux/kernel.h

@@ -22,4 +22,5 @@
 #define __releases(x)
 #define __must_hold(x)
 
+#define EXPORT_PER_CPU_SYMBOL_GPL(x)
 #endif /* _KERNEL_H */

tools/testing/radix-tree/linux/local_lock.h

@@ -0,0 +1,8 @@
+#ifndef _LINUX_LOCAL_LOCK
+#define _LINUX_LOCAL_LOCK
+typedef struct { } local_lock_t;
+
+static inline void local_lock(local_lock_t *lock) { }
+static inline void local_unlock(local_lock_t *lock) { }
+#define INIT_LOCAL_LOCK(x) { }
+#endif

tools/testing/radix-tree/test.h

@@ -56,8 +56,4 @@ int root_tag_get(struct radix_tree_root *root, unsigned int tag);
 unsigned long node_maxindex(struct radix_tree_node *);
 unsigned long shift_maxindex(unsigned int shift);
 int radix_tree_cpu_dead(unsigned int cpu);
-struct radix_tree_preload {
-	unsigned nr;
-	struct radix_tree_node *nodes;
-};
 extern struct radix_tree_preload radix_tree_preloads;