From 3c4372210e7824666fcfcc7c9c66fb5ea6f15885 Mon Sep 17 00:00:00 2001
From: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Date: Tue, 15 Nov 2016 10:34:22 +0100
Subject: [PATCH] core: remove redundant datastructure

Avl allocator provides a method to lookup any element, which is sufficient
to find all regions to destruct.

Issue #2173
---
 .../src/core/include/region_map_component.h   |  4 --
 repos/base/src/core/region_map_component.cc   | 37 ++++---------------
 2 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/repos/base/src/core/include/region_map_component.h b/repos/base/src/core/include/region_map_component.h
index 4346b3843..92b58d3e0 100644
--- a/repos/base/src/core/include/region_map_component.h
+++ b/repos/base/src/core/include/region_map_component.h
@@ -285,12 +285,8 @@ class Genode::Region_map_component : public Genode::Weak_object<Genode::Region_m
 		typedef Tslab<Rm_region_ref, get_page_size() - Sliced_heap::meta_data_size()>
 		        Ref_slab;
 
-		Ref_slab                      _ref_slab;     /* backing store for
-		                                                region list */
 		Allocator_avl_tpl<Rm_region>  _map;          /* region map for attach,
 		                                                detach, pagefaults */
-		List<Rm_region_ref>           _regions;      /* region list for destruction */
-
 		Fifo<Rm_faulter>              _faulters;     /* list of threads that faulted at
 		                                                the region map and wait
 		                                                for fault resolution */
diff --git a/repos/base/src/core/region_map_component.cc b/repos/base/src/core/region_map_component.cc
index 0c8ff56b8..004442d8e 100644
--- a/repos/base/src/core/region_map_component.cc
+++ b/repos/base/src/core/region_map_component.cc
@@ -392,16 +392,6 @@ Region_map_component::attach(Dataspace_capability ds_cap, size_t size,
 		_map.metadata(r, Rm_region((addr_t)r, size, true, dsc, offset, this));
 		Rm_region *region = _map.metadata(r);
 
-		/* also update region list */
-		Rm_region_ref *p;
-		try { p = new(&_ref_slab) Rm_region_ref(region); }
-		catch (Allocator::Out_of_memory) {
-			_map.free(r);
-			throw Out_of_metadata();
-		}
-
-		_regions.insert(p);
-
 		/* inform dataspace about attachment */
 		dsc->attached_to(region);
 
@@ -552,16 +542,6 @@ void Region_map_component::detach(Local_addr local_addr)
 	 * region maps.
 	 */
 	unmap_managed(this, &region, 1);
-
-	/* update region list */
-	Rm_region_ref *p = _regions.first();
-	for (; p; p = p->next())
-		if (p->region() == region_ptr) break;
-
-	if (p) {
-		_regions.remove(p);
-		destroy(&_ref_slab, p);
-	}
 }
 
 
@@ -641,7 +621,6 @@ Region_map_component::Region_map_component(Rpc_entrypoint   &ep,
 :
 	_ds_ep(&ep), _thread_ep(&ep), _session_ep(&ep),
 	_md_alloc(md_alloc),
-	_ref_slab(&_md_alloc),
 	_map(&_md_alloc), _pager_ep(&pager_ep),
 	_ds(align_addr(vm_size, get_page_size_log2())),
 	_ds_cap(_type_deduction_helper(_ds_ep->manage(&_ds)))
@@ -687,17 +666,17 @@ Region_map_component::~Region_map_component()
 	} while (cl);
 
 	/* detach all regions */
-	Rm_region_ref *ref;
-	do {
-		void * local_addr;
+	while (true) {
+		addr_t out_addr = 0;
+
 		{
 			Lock::Guard lock_guard(_lock);
-			ref = _ref_slab.first_object();
-			if (!ref) break;
-			local_addr = reinterpret_cast<void *>(ref->region()->base());
+			if (!_map.any_block_addr(&out_addr))
+				break;
 		}
-		detach(local_addr);
-	} while (ref);
+
+		detach(out_addr);
+	}
 
 	/* revoke dataspace representation */
 	_ds_ep->dissolve(&_ds);