IB/hfi1: Add filter callback

This commit adds a filter callback, which can be used to filter
out interval RB nodes matching a certain interval down to a
single one.

This is needed for the upcoming SDMA-side caching where buffers
will need to be filtered by their virtual address.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/staging/rdma/hfi1/mmu_rb.c

@@ -181,13 +181,22 @@ static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 					   unsigned long addr,
 					   unsigned long len)
 {
-	struct mmu_rb_node *node;
+	struct mmu_rb_node *node = NULL;
 
 	hfi1_cdbg(MMU, "Searching for addr 0x%llx, len %u", addr, len);
-	node = __mmu_int_rb_iter_first(handler->root, addr, len);
-	if (node)
-		hfi1_cdbg(MMU, "Found node addr 0x%llx, len %u", node->addr,
-			  node->len);
+	if (!handler->ops->filter) {
+		node = __mmu_int_rb_iter_first(handler->root, addr,
+					       (addr + len) - 1);
+	} else {
+		for (node = __mmu_int_rb_iter_first(handler->root, addr,
+						    (addr + len) - 1);
+		     node;
+		     node = __mmu_int_rb_iter_next(node, addr,
+						   (addr + len) - 1)) {
+			if (handler->ops->filter(node, addr, len))
+				return node;
+		}
+	}
 	return node;
 }
 

drivers/staging/rdma/hfi1/mmu_rb.h

@@ -57,6 +57,7 @@ struct mmu_rb_node {
 };
 
 struct mmu_rb_ops {
+	bool (*filter)(struct mmu_rb_node *, unsigned long, unsigned long);
 	int (*insert)(struct rb_root *, struct mmu_rb_node *);
 	void (*remove)(struct rb_root *, struct mmu_rb_node *, bool);
 	int (*invalidate)(struct rb_root *, struct mmu_rb_node *);