1 files changed, 236 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.c b/drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.c
new file mode 100644
index 000000000000..d135ad90d914
--- /dev/null
+++ b/drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.c
@@ -0,0 +1,236 @@
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/list_sort.h>
+
+#include <linux/interval_tree_generic.h>
+#include "usnic_uiom_interval_tree.h"
+
+#define START(node) ((node)->start)
+#define LAST(node) ((node)->last)
+
+#define MAKE_NODE(node, start, end, ref_cnt, flags, err, err_out)	\
+		do {							\
+			node = usnic_uiom_interval_node_alloc(start,	\
+					end, ref_cnt, flags);		\
+				if (!node) {				\
+					err = -ENOMEM;			\
+					goto err_out;			\
+				}					\
+		} while (0)
+
+#define MARK_FOR_ADD(node, list) (list_add_tail(&node->link, list))
+
+#define MAKE_NODE_AND_APPEND(node, start, end, ref_cnt, flags, err,	\
+				err_out, list)				\
+				do {					\
+					MAKE_NODE(node, start, end,	\
+						ref_cnt, flags, err,	\
+						err_out);		\
+					MARK_FOR_ADD(node, list);	\
+				} while (0)
+
+#define FLAGS_EQUAL(flags1, flags2, mask)				\
+			(((flags1) & (mask)) == ((flags2) & (mask)))
+
+static struct usnic_uiom_interval_node*
+usnic_uiom_interval_node_alloc(long int start, long int last, int ref_cnt,
+				int flags)
+{
+	struct usnic_uiom_interval_node *interval = kzalloc(sizeof(*interval),
+								GFP_ATOMIC);
+	if (!interval)
+		return NULL;
+
+	interval->start = start;
+	interval->last = last;
+	interval->flags = flags;
+	interval->ref_cnt = ref_cnt;
+
+	return interval;
+}
+
+static int interval_cmp(void *priv, struct list_head *a, struct list_head *b)
+{
+	struct usnic_uiom_interval_node *node_a, *node_b;
+
+	node_a = list_entry(a, struct usnic_uiom_interval_node, link);
+	node_b = list_entry(b, struct usnic_uiom_interval_node, link);
+
+	/* long to int */
+	if (node_a->start < node_b->start)
+		return -1;
+	else if (node_a->start > node_b->start)
+		return 1;
+
+	return 0;
+}
+
+static void
+find_intervals_intersection_sorted(struct rb_root *root, unsigned long start,
+					unsigned long last,
+					struct list_head *list)
+{
+	struct usnic_uiom_interval_node *node;
+
+	INIT_LIST_HEAD(list);
+
+	for (node = usnic_uiom_interval_tree_iter_first(root, start, last);
+		node;
+		node = usnic_uiom_interval_tree_iter_next(node, start, last))
+		list_add_tail(&node->link, list);
+
+	list_sort(NULL, list, interval_cmp);
+}
+
+int usnic_uiom_get_intervals_diff(unsigned long start, unsigned long last,
+					int flags, int flag_mask,
+					struct rb_root *root,
+					struct list_head *diff_set)
+{
+	struct usnic_uiom_interval_node *interval, *tmp;
+	int err = 0;
+	long int pivot = start;
+	LIST_HEAD(intersection_set);
+
+	INIT_LIST_HEAD(diff_set);
+
+	find_intervals_intersection_sorted(root, start, last,
+						&intersection_set);
+
+	list_for_each_entry(interval, &intersection_set, link) {
+		if (pivot < interval->start) {
+			MAKE_NODE_AND_APPEND(tmp, pivot, interval->start - 1,
+						1, flags, err, err_out,
+						diff_set);
+			pivot = interval->start;
+		}
+
+		/*
+		 * Invariant: Set [start, pivot] is either in diff_set or root,
+		 * but not in both.
+		 */
+
+		if (pivot > interval->last) {
+			continue;
+		} else if (pivot <= interval->last &&
+				FLAGS_EQUAL(interval->flags, flags,
+				flag_mask)) {
+			pivot = interval->last + 1;
+		}
+	}
+
+	if (pivot <= last)
+		MAKE_NODE_AND_APPEND(tmp, pivot, last, 1, flags, err, err_out,
+					diff_set);
+
+	return 0;
+
+err_out:
+	list_for_each_entry_safe(interval, tmp, diff_set, link) {
+		list_del(&interval->link);
+		kfree(interval);
+	}
+
+	return err;
+}
+
+void usnic_uiom_put_interval_set(struct list_head *intervals)
+{
+	struct usnic_uiom_interval_node *interval, *tmp;
+	list_for_each_entry_safe(interval, tmp, intervals, link)
+		kfree(interval);
+}
+
+int usnic_uiom_insert_interval(struct rb_root *root, unsigned long start,
+				unsigned long last, int flags)
+{
+	struct usnic_uiom_interval_node *interval, *tmp;
+	unsigned long istart, ilast;
+	int iref_cnt, iflags;
+	unsigned long lpivot = start;
+	int err = 0;
+	LIST_HEAD(to_add);
+	LIST_HEAD(intersection_set);
+
+	find_intervals_intersection_sorted(root, start, last,
+						&intersection_set);
+
+	list_for_each_entry(interval, &intersection_set, link) {
+		/*
+		 * Invariant - lpivot is the left edge of next interval to be
+		 * inserted
+		 */
+		istart = interval->start;
+		ilast = interval->last;
+		iref_cnt = interval->ref_cnt;
+		iflags = interval->flags;
+
+		if (istart < lpivot) {
+			MAKE_NODE_AND_APPEND(tmp, istart, lpivot - 1, iref_cnt,
+						iflags, err, err_out, &to_add);
+		} else if (istart > lpivot) {
+			MAKE_NODE_AND_APPEND(tmp, lpivot, istart - 1, 1, flags,
+						err, err_out, &to_add);
+			lpivot = istart;
+		} else {
+			lpivot = istart;
+		}
+
+		if (ilast > last) {
+			MAKE_NODE_AND_APPEND(tmp, lpivot, last, iref_cnt + 1,
+						iflags | flags, err, err_out,
+						&to_add);
+			MAKE_NODE_AND_APPEND(tmp, last + 1, ilast, iref_cnt,
+						iflags, err, err_out, &to_add);
+		} else {
+			MAKE_NODE_AND_APPEND(tmp, lpivot, ilast, iref_cnt + 1,
+						iflags | flags, err, err_out,
+						&to_add);
+		}
+
+		lpivot = ilast + 1;
+	}
+
+	if (lpivot <= last)
+		MAKE_NODE_AND_APPEND(tmp, lpivot, last, 1, flags, err, err_out,
+					&to_add);
+
+	list_for_each_entry_safe(interval, tmp, &intersection_set, link) {
+		usnic_uiom_interval_tree_remove(interval, root);
+		kfree(interval);
+	}
+
+	list_for_each_entry(interval, &to_add, link)
+		usnic_uiom_interval_tree_insert(interval, root);
+
+	return 0;
+
+err_out:
+	list_for_each_entry_safe(interval, tmp, &to_add, link)
+		kfree(interval);
+
+	return err;
+}
+
+void usnic_uiom_remove_interval(struct rb_root *root, unsigned long start,
+				unsigned long last, struct list_head *removed)
+{
+	struct usnic_uiom_interval_node *interval;
+
+	for (interval = usnic_uiom_interval_tree_iter_first(root, start, last);
+			interval;
+			interval = usnic_uiom_interval_tree_iter_next(interval,
+									start,
+									last)) {
+		if (--interval->ref_cnt == 0)
+			list_add_tail(&interval->link, removed);
+	}
+
+	list_for_each_entry(interval, removed, link)
+		usnic_uiom_interval_tree_remove(interval, root);
+}
+
+INTERVAL_TREE_DEFINE(struct usnic_uiom_interval_node, rb,
+			unsigned long, __subtree_last,
+			START, LAST, , usnic_uiom_interval_tree)