On Mon, Dec 22, 2025 at 02:40:37PM +0200, Edward Srouji wrote:

+static int compare_keys(struct ib_frmr_key *key1, struct ib_frmr_key *key2)
+{
+	int res;
+
+	res = key1->ats - key2->ats;
+	if (res)
+		return res;
+
+	res = key1->access_flags - key2->access_flags;
+	if (res)
+		return res;
+
+	res = key1->vendor_key - key2->vendor_key;
+	if (res)
+		return res;
+
+	res = key1->kernel_vendor_key - key2->kernel_vendor_key;
+	if (res)
+		return res;

This stuff should be using cmp_int().

+static struct ib_frmr_pool *ib_frmr_pool_find(struct ib_frmr_pools *pools,
+					      struct ib_frmr_key *key)
+{
+	struct rb_node *node = pools->rb_root.rb_node;
+	struct ib_frmr_pool *pool;
+	int cmp;
+
+	/* find operation is done under read lock for performance reasons.
+	 * The case of threads failing to find the same pool and creating it
+	 * is handled by the create_frmr_pool function.
+	 */
+	read_lock(&pools->rb_lock);
+	while (node) {
+		pool = rb_entry(node, struct ib_frmr_pool, node);
+		cmp = compare_keys(&pool->key, key);
+		if (cmp < 0) {
+			node = node->rb_right;
+		} else if (cmp > 0) {
+			node = node->rb_left;
+		} else {
+			read_unlock(&pools->rb_lock);
+			return pool;
+		}

Use the rb_find() helper

+static struct ib_frmr_pool *create_frmr_pool(struct ib_device *device,
+					     struct ib_frmr_key *key)
+{
+	struct rb_node **new = &device->frmr_pools->rb_root.rb_node,
+		       *parent = NULL;
+	struct ib_frmr_pools *pools = device->frmr_pools;
+	struct ib_frmr_pool *pool;
+	int cmp;
+
+	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+	if (!pool)
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(&pool->key, key, sizeof(*key));
+	INIT_LIST_HEAD(&pool->queue.pages_list);
+	spin_lock_init(&pool->lock);
+
+	write_lock(&pools->rb_lock);
+	while (*new) {
+		parent = *new;
+		cmp = compare_keys(
+			&rb_entry(parent, struct ib_frmr_pool, node)->key, key);
+		if (cmp < 0)
+			new = &((*new)->rb_left);
+		else
+			new = &((*new)->rb_right);
+		/* If a different thread has already created the pool, return
+		 * it. The insert operation is done under the write lock so we
+		 * are sure that the pool is not inserted twice.
+		 */
+		if (cmp == 0) {
+			write_unlock(&pools->rb_lock);
+			kfree(pool);
+			return rb_entry(parent, struct ib_frmr_pool, node);
+		}
+	}
+
+	rb_link_node(&pool->node, parent, new);

I think this is rb_find_add() ?

Jason