diff --git a/include/libtorrent/Makefile.am b/include/libtorrent/Makefile.am
index 8879a9232..139458405 100644
--- a/include/libtorrent/Makefile.am
+++ b/include/libtorrent/Makefile.am
@@ -158,6 +158,7 @@ nobase_include_HEADERS = \
   \
   aux_/allocating_handler.hpp       \
   aux_/bind_to_device.hpp           \
+  aux_/block_cache_reference.hpp    \
   aux_/cpuid.hpp                    \
   aux_/disable_warnings_push.hpp    \
   aux_/disable_warnings_pop.hpp     \
diff --git a/include/libtorrent/aux_/block_cache_reference.hpp b/include/libtorrent/aux_/block_cache_reference.hpp
new file mode 100644
index 000000000..dac5f5955
--- /dev/null
+++ b/include/libtorrent/aux_/block_cache_reference.hpp
@@ -0,0 +1,50 @@
+/*
+
+Copyright (c) 2010-2016, Arvid Norberg
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in
+      the documentation and/or other materials provided with the distribution.
+    * Neither the name of the author nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#ifndef TORRENT_BLOCK_CACHE_REFERENCE_HPP
+#define TORRENT_BLOCK_CACHE_REFERENCE_HPP
+
+namespace libtorrent {
+namespace aux {
+
+	struct block_cache_reference
+	{
+		void* storage;
+		int piece;
+		int block;
+	};
+
+}
+}
+
+#endif
+
diff --git a/include/libtorrent/aux_/session_interface.hpp b/include/libtorrent/aux_/session_interface.hpp
index 93462c558..ff97800fc 100644
--- a/include/libtorrent/aux_/session_interface.hpp
+++ b/include/libtorrent/aux_/session_interface.hpp
@@ -39,14 +39,11 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/io_service.hpp"
 #include "libtorrent/time.hpp"
 #include "libtorrent/disk_buffer_holder.hpp"
+#include "libtorrent/error_code.hpp"
 
 #include <functional>
 #include <memory>
 
-#ifndef TORRENT_DISABLE_DHT
-#include "libtorrent/socket.hpp"
-#endif
-
 #include "libtorrent/socket.hpp" // for tcp::endpoint
 
 #include "libtorrent/aux_/disable_warnings_push.hpp"
diff --git a/include/libtorrent/block_cache.hpp b/include/libtorrent/block_cache.hpp
index 41e4e2b26..fc3a169a0 100644
--- a/include/libtorrent/block_cache.hpp
+++ b/include/libtorrent/block_cache.hpp
@@ -54,9 +54,12 @@ namespace libtorrent
 	struct disk_io_job;
 	struct storage_interface;
 	struct cache_status;
-	struct block_cache_reference;
 	struct counters;
-	namespace aux { struct session_settings; }
+	namespace aux
+	{
+		struct session_settings;
+		struct block_cache_reference;
+	}
 #if TORRENT_USE_ASSERTS
 	class file_storage;
 #endif
@@ -346,7 +349,7 @@ namespace libtorrent
 		int pad_job(disk_io_job const* j, int blocks_in_piece
 			, int read_ahead) const;
 
-		void reclaim_block(block_cache_reference const& ref);
+		void reclaim_block(aux::block_cache_reference const& ref);
 
 		// returns a range of all pieces. This might be a very
 		// long list, use carefully
@@ -408,7 +411,7 @@ namespace libtorrent
 
 		// looks for this piece in the cache. If it's there, returns a pointer
 		// to it, otherwise 0.
-		cached_piece_entry* find_piece(block_cache_reference const& ref);
+		cached_piece_entry* find_piece(aux::block_cache_reference const& ref);
 		cached_piece_entry* find_piece(disk_io_job const* j);
 		cached_piece_entry* find_piece(storage_interface* st, int piece);
 
diff --git a/include/libtorrent/bt_peer_connection.hpp b/include/libtorrent/bt_peer_connection.hpp
index 098090ac4..74f5c5046 100644
--- a/include/libtorrent/bt_peer_connection.hpp
+++ b/include/libtorrent/bt_peer_connection.hpp
@@ -315,8 +315,8 @@ public:
 		// peer_connection functions of the same names
 		virtual void append_const_send_buffer(char const* buffer, int size
 			, chained_buffer::free_buffer_fun destructor = &nop
-			, void* userdata = nullptr, block_cache_reference ref
-			= block_cache_reference()) override;
+			, void* userdata = nullptr, aux::block_cache_reference ref
+			= aux::block_cache_reference()) override;
 
 private:
 
diff --git a/include/libtorrent/chained_buffer.hpp b/include/libtorrent/chained_buffer.hpp
index 39147f441..4a1fbb223 100644
--- a/include/libtorrent/chained_buffer.hpp
+++ b/include/libtorrent/chained_buffer.hpp
@@ -34,7 +34,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #define TORRENT_CHAINED_BUFFER_HPP_INCLUDED
 
 #include "libtorrent/config.hpp"
-#include "libtorrent/disk_io_job.hpp" // for block_cache_reference
+#include "libtorrent/aux_/block_cache_reference.hpp"
 #include "libtorrent/debug.hpp"
 #include "libtorrent/buffer.hpp"
 
@@ -60,7 +60,7 @@ namespace libtorrent
 
 		// destructs/frees the buffer (1st arg) with
 		// 2nd argument as userdata
-		typedef void (*free_buffer_fun)(char*, void*, block_cache_reference ref);
+		typedef void (*free_buffer_fun)(char*, void*, aux::block_cache_reference ref);
 
 		struct buffer_t
 		{
@@ -73,7 +73,7 @@ namespace libtorrent
 			char* start; // the first byte to send/receive in the buffer
 			int size; // the total size of the buffer
 			int used_size; // this is the number of bytes to send/receive
-			block_cache_reference ref;
+			aux::block_cache_reference ref;
 		};
 
 		bool empty() const { return m_bytes == 0; }
@@ -85,11 +85,11 @@ namespace libtorrent
 		//TODO: 3 use span<> instead of (buffer,s)
 		void append_buffer(char* buffer, int s, int used_size
 			, free_buffer_fun destructor, void* userdata
-			, block_cache_reference ref = block_cache_reference());
+			, aux::block_cache_reference ref = aux::block_cache_reference());
 
 		void prepend_buffer(char* buffer, int s, int used_size
 			, free_buffer_fun destructor, void* userdata
-			, block_cache_reference ref = block_cache_reference());
+			, aux::block_cache_reference ref = aux::block_cache_reference());
 
 		// returns the number of bytes available at the
 		// end of the last chained buffer.
diff --git a/include/libtorrent/disk_buffer_holder.hpp b/include/libtorrent/disk_buffer_holder.hpp
index 7335c5e25..130b0e7e2 100644
--- a/include/libtorrent/disk_buffer_holder.hpp
+++ b/include/libtorrent/disk_buffer_holder.hpp
@@ -35,7 +35,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/config.hpp"
 #include "libtorrent/assert.hpp"
-#include "libtorrent/disk_io_job.hpp" // for block_cache_reference
+#include "libtorrent/aux_/block_cache_reference.hpp"
 #include "libtorrent/span.hpp"
 
 #include <memory>
@@ -49,7 +49,7 @@ namespace libtorrent
 	struct TORRENT_EXTRA_EXPORT buffer_allocator_interface
 	{
 		virtual void free_disk_buffer(char* b) = 0;
-		virtual void reclaim_blocks(span<block_cache_reference> refs) = 0;
+		virtual void reclaim_blocks(span<aux::block_cache_reference> refs) = 0;
 		virtual disk_buffer_holder allocate_disk_buffer(char const* category) = 0;
 		virtual disk_buffer_holder allocate_disk_buffer(bool& exceeded
 			, std::shared_ptr<disk_observer> o
@@ -79,7 +79,7 @@ namespace libtorrent
 		// using a disk buffer pool directly (there's only one
 		// disk_buffer_pool per session)
 		disk_buffer_holder(buffer_allocator_interface& alloc
-			, block_cache_reference const& ref, char* buf) noexcept;
+			, aux::block_cache_reference const& ref, char* buf) noexcept;
 
 		// frees any unreleased disk buffer held by this object
 		~disk_buffer_holder();
@@ -96,7 +96,7 @@ namespace libtorrent
 		// (or nullptr by default). If it's already holding a
 		// disk buffer, it will first be freed.
 		void reset(char* buf = 0);
-		void reset(block_cache_reference const& ref, char* buf);
+		void reset(aux::block_cache_reference const& ref, char* buf);
 
 		// swap pointers of two disk buffer holders.
 		void swap(disk_buffer_holder& h) noexcept
@@ -106,7 +106,7 @@ namespace libtorrent
 			std::swap(h.m_ref, m_ref);
 		}
 
-		block_cache_reference ref() const noexcept { return m_ref; }
+		aux::block_cache_reference ref() const noexcept { return m_ref; }
 
 		// implicitly convertible to true if the object is currently holding a
 		// buffer
@@ -116,7 +116,7 @@ namespace libtorrent
 
 		buffer_allocator_interface* m_allocator;
 		char* m_buf;
-		block_cache_reference m_ref;
+		aux::block_cache_reference m_ref;
 	};
 
 }
diff --git a/include/libtorrent/disk_io_job.hpp b/include/libtorrent/disk_io_job.hpp
index 3221f767f..26647fd6f 100644
--- a/include/libtorrent/disk_io_job.hpp
+++ b/include/libtorrent/disk_io_job.hpp
@@ -35,6 +35,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/error_code.hpp"
 #include "libtorrent/tailqueue.hpp"
+#include "libtorrent/aux_/block_cache_reference.hpp"
 
 #include <string>
 #include <vector>
@@ -48,13 +49,6 @@ namespace libtorrent
 	class torrent_info;
 	struct add_torrent_params;
 
-	struct block_cache_reference
-	{
-		void* storage;
-		int piece;
-		int block;
-	};
-
 	// disk_io_jobs are allocated in a pool allocator in disk_io_thread
 	// they are always allocated from the network thread, posted
 	// (as pointers) to the disk I/O thread, and then passed back
@@ -178,7 +172,7 @@ namespace libtorrent
 			// is set in a response to a read, the buffer needs to
 			// be de-referenced by sending a reclaim_block message
 			// back to the disk thread
-			block_cache_reference ref;
+			aux::block_cache_reference ref;
 
 			// for read and write, the offset into the piece
 			// the read or write should start
diff --git a/include/libtorrent/disk_io_thread.hpp b/include/libtorrent/disk_io_thread.hpp
index a46182a0f..c2a7812df 100644
--- a/include/libtorrent/disk_io_thread.hpp
+++ b/include/libtorrent/disk_io_thread.hpp
@@ -60,6 +60,11 @@ namespace libtorrent
 	struct counters;
 	class alert_manager;
 
+	namespace aux
+	{
+		struct block_cache_reference;
+	}
+
 	struct cached_piece_info
 	{
 		storage_interface* storage;
@@ -327,7 +332,7 @@ namespace libtorrent
 		void clear_piece(storage_interface* storage, int index) override;
 
 		// implements buffer_allocator_interface
-		void reclaim_blocks(span<block_cache_reference> ref) override;
+		void reclaim_blocks(span<aux::block_cache_reference> ref) override;
 		void free_disk_buffer(char* buf) override { m_disk_cache.free_buffer(buf); }
 		disk_buffer_holder allocate_disk_buffer(char const* category) override
 		{
diff --git a/include/libtorrent/extensions.hpp b/include/libtorrent/extensions.hpp
index 3c6640fbb..6699918f9 100644
--- a/include/libtorrent/extensions.hpp
+++ b/include/libtorrent/extensions.hpp
@@ -164,6 +164,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/sha1_hash.hpp"
 #include "libtorrent/string_view.hpp"
 #include "libtorrent/socket.hpp"
+#include "libtorrent/error_code.hpp"
 
 namespace libtorrent
 {
diff --git a/include/libtorrent/peer_connection.hpp b/include/libtorrent/peer_connection.hpp
index a34dff3b4..be37a3910 100644
--- a/include/libtorrent/peer_connection.hpp
+++ b/include/libtorrent/peer_connection.hpp
@@ -148,7 +148,7 @@ namespace libtorrent
 	};
 
 	// internal
-	inline void nop(char*, void*, block_cache_reference) {}
+	inline void nop(char*, void*, aux::block_cache_reference) {}
 
 	struct TORRENT_EXTRA_EXPORT peer_connection_hot_members
 	{
@@ -630,13 +630,13 @@ namespace libtorrent
 
 		void append_send_buffer(char* buffer, int size
 			, chained_buffer::free_buffer_fun destructor = &nop
-			, void* userdata = nullptr, block_cache_reference ref
-			= block_cache_reference());
+			, void* userdata = nullptr, aux::block_cache_reference ref
+			= aux::block_cache_reference());
 
 		virtual void append_const_send_buffer(char const* buffer, int size
 			, chained_buffer::free_buffer_fun destructor = &nop
-			, void* userdata = nullptr, block_cache_reference ref
-			= block_cache_reference());
+			, void* userdata = nullptr, aux::block_cache_reference ref
+			= aux::block_cache_reference());
 
 		int outstanding_bytes() const { return m_outstanding_bytes; }
 
diff --git a/include/libtorrent/storage.hpp b/include/libtorrent/storage.hpp
index 4e8761501..65d7873ca 100644
--- a/include/libtorrent/storage.hpp
+++ b/include/libtorrent/storage.hpp
@@ -54,6 +54,8 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/bitfield.hpp"
 #include "libtorrent/performance_counters.hpp"
 #include "libtorrent/span.hpp"
+#include "libtorrent/tailqueue.hpp"
+#include "libtorrent/disk_io_job.hpp"
 
 // OVERVIEW
 //
diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index fa8f954a7..633555a8d 100644
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -92,6 +92,7 @@ namespace libtorrent
 	struct storage_interface;
 	class bt_peer_connection;
 	struct listen_socket_t;
+	struct disk_io_job;
 
 	enum class waste_reason
 	{
diff --git a/src/block_cache.cpp b/src/block_cache.cpp
index 6db414bf4..63a7b1c12 100644
--- a/src/block_cache.cpp
+++ b/src/block_cache.cpp
@@ -41,6 +41,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/alloca.hpp"
 #include "libtorrent/performance_counters.hpp"
 #include "libtorrent/aux_/time.hpp"
+#include "libtorrent/aux_/block_cache_reference.hpp"
 
 /*
 
@@ -1779,7 +1780,7 @@ int block_cache::copy_from_piece(cached_piece_entry* const pe
 	return j->d.io.buffer_size;
 }
 
-void block_cache::reclaim_block(block_cache_reference const& ref)
+void block_cache::reclaim_block(aux::block_cache_reference const& ref)
 {
 	cached_piece_entry* pe = find_piece(ref);
 	TORRENT_ASSERT(pe);
@@ -1817,7 +1818,7 @@ bool block_cache::maybe_free_piece(cached_piece_entry* pe)
 	return true;
 }
 
-cached_piece_entry* block_cache::find_piece(block_cache_reference const& ref)
+cached_piece_entry* block_cache::find_piece(aux::block_cache_reference const& ref)
 {
 	return find_piece(static_cast<storage_interface*>(ref.storage), ref.piece);
 }
diff --git a/src/bt_peer_connection.cpp b/src/bt_peer_connection.cpp
index 46bb77d4e..b6074e39d 100644
--- a/src/bt_peer_connection.cpp
+++ b/src/bt_peer_connection.cpp
@@ -725,7 +725,7 @@ namespace libtorrent
 
 	namespace {
 		void regular_c_free(char* buf, void* /* userdata */
-			, block_cache_reference /* ref */)
+			, aux::block_cache_reference /* ref */)
 		{
 			std::free(buf);
 		}
@@ -735,7 +735,7 @@ namespace libtorrent
 
 	void bt_peer_connection::append_const_send_buffer(char const* buffer, int size
 		, chained_buffer::free_buffer_fun destructor, void* userdata
-		, block_cache_reference ref)
+		, aux::block_cache_reference ref)
 	{
 #if !defined(TORRENT_DISABLE_ENCRYPTION) && !defined(TORRENT_DISABLE_EXTENSIONS)
 		if (!m_enc_handler.is_send_plaintext())
@@ -2433,14 +2433,14 @@ namespace libtorrent
 	namespace {
 
 	void buffer_reclaim_block(char* /* buffer */, void* userdata
-		, block_cache_reference ref)
+		, aux::block_cache_reference ref)
 	{
 		buffer_allocator_interface* buf = static_cast<buffer_allocator_interface*>(userdata);
 		buf->reclaim_blocks(ref);
 	}
 
 	void buffer_free_disk_buf(char* buffer, void* userdata
-		, block_cache_reference /* ref */)
+		, aux::block_cache_reference /* ref */)
 	{
 		buffer_allocator_interface* buf = static_cast<buffer_allocator_interface*>(userdata);
 		buf->free_disk_buffer(buffer);
diff --git a/src/chained_buffer.cpp b/src/chained_buffer.cpp
index de1f2b945..85382a3ac 100644
--- a/src/chained_buffer.cpp
+++ b/src/chained_buffer.cpp
@@ -68,7 +68,7 @@ namespace libtorrent
 
 	void chained_buffer::append_buffer(char* buffer, int s, int used_size
 		, free_buffer_fun destructor, void* userdata
-		, block_cache_reference ref)
+		, aux::block_cache_reference ref)
 	{
 		TORRENT_ASSERT(is_single_thread());
 		TORRENT_ASSERT(s >= used_size);
@@ -89,7 +89,7 @@ namespace libtorrent
 
 	void chained_buffer::prepend_buffer(char* buffer, int s, int used_size
 		, free_buffer_fun destructor, void* userdata
-		, block_cache_reference ref)
+		, aux::block_cache_reference ref)
 	{
 		TORRENT_ASSERT(s >= used_size);
 		buffer_t b;
diff --git a/src/disk_buffer_holder.cpp b/src/disk_buffer_holder.cpp
index a7408556d..6cf5110eb 100644
--- a/src/disk_buffer_holder.cpp
+++ b/src/disk_buffer_holder.cpp
@@ -32,6 +32,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/disk_buffer_holder.hpp"
 #include "libtorrent/storage.hpp" // for storage_interface
+#include "libtorrent/aux_/block_cache_reference.hpp"
 
 namespace libtorrent
 {
@@ -58,7 +59,7 @@ namespace libtorrent
 	}
 
 	disk_buffer_holder::disk_buffer_holder(buffer_allocator_interface& alloc
-		, block_cache_reference const& ref, char* buf) noexcept
+		, aux::block_cache_reference const& ref, char* buf) noexcept
 		: m_allocator(&alloc), m_buf(buf), m_ref(ref)
 	{
 		TORRENT_ASSERT(m_ref.storage == nullptr || m_ref.piece >= 0);
@@ -69,7 +70,7 @@ namespace libtorrent
 			|| m_ref.block <= static_cast<storage_interface*>(m_ref.storage)->files()->piece_length() / 0x4000);
 	}
 
-	void disk_buffer_holder::reset(block_cache_reference const& ref, char* buf)
+	void disk_buffer_holder::reset(aux::block_cache_reference const& ref, char* buf)
 	{
 		if (m_ref.storage) m_allocator->reclaim_blocks(m_ref);
 		else if (m_buf) m_allocator->free_disk_buffer(m_buf);
diff --git a/src/disk_io_thread.cpp b/src/disk_io_thread.cpp
index 4bdeac6c8..7a1cc087f 100644
--- a/src/disk_io_thread.cpp
+++ b/src/disk_io_thread.cpp
@@ -239,7 +239,7 @@ namespace libtorrent
 		m_hash_threads.abort(wait);
 	}
 
-	void disk_io_thread::reclaim_blocks(span<block_cache_reference> refs)
+	void disk_io_thread::reclaim_blocks(span<aux::block_cache_reference> refs)
 	{
 		TORRENT_ASSERT(m_magic == 0x1337);
 
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 9d59497ca..1b3058f95 100644
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -61,6 +61,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/ip_filter.hpp"
 #include "libtorrent/kademlia/node_id.hpp"
 #include "libtorrent/close_reason.hpp"
+#include "libtorrent/disk_io_job.hpp"
 #include "libtorrent/aux_/has_block.hpp"
 #include "libtorrent/aux_/time.hpp"
 
@@ -5676,7 +5677,7 @@ namespace libtorrent
 
 	void peer_connection::append_send_buffer(char* buffer, int size
 		, chained_buffer::free_buffer_fun destructor, void* userdata
-		, block_cache_reference ref)
+		, aux::block_cache_reference ref)
 	{
 		TORRENT_ASSERT(is_single_thread());
 		m_send_buffer.append_buffer(buffer, size, size, destructor
@@ -5685,7 +5686,7 @@ namespace libtorrent
 
 	void peer_connection::append_const_send_buffer(char const* buffer, int size
 		, chained_buffer::free_buffer_fun destructor, void* userdata
-		, block_cache_reference ref)
+		, aux::block_cache_reference ref)
 	{
 		TORRENT_ASSERT(is_single_thread());
 		m_send_buffer.append_buffer(const_cast<char*>(buffer), size, size, destructor
@@ -5702,7 +5703,7 @@ namespace libtorrent
 	}
 
 	namespace {
-		void session_free_buffer(char* buffer, void* userdata, block_cache_reference)
+		void session_free_buffer(char* buffer, void* userdata, aux::block_cache_reference)
 		{
 			aux::session_interface* ses = static_cast<aux::session_interface*>(userdata);
 			ses->free_buffer(buffer);
diff --git a/test/test_buffer.cpp b/test/test_buffer.cpp
index 6d1e561ea..fbc90bc4e 100644
--- a/test/test_buffer.cpp
+++ b/test/test_buffer.cpp
@@ -140,7 +140,7 @@ TORRENT_TEST(buffer_move_assign)
 
 std::set<char*> buffer_list;
 
-void free_buffer(char* m, void* userdata, block_cache_reference ref)
+void free_buffer(char* m, void* userdata, aux::block_cache_reference ref)
 {
 	TEST_CHECK(userdata == (void*)0x1337);
 	std::set<char*>::iterator i = buffer_list.find(m);