Generic bi-directional map, and related initialisation functions. At the moment

a single map is used to store mappings between sharing handles and disk blocks.
This is used to share pages which store data read of the same blocks on
(virtual) disk.
Note that the map is stored in a shared memory region, as it needs to be
accessed by multiple tapdisk processes. This complicates memory allocation
(malloc cannot be used), prevents poniters to be stored directly (as the shared
memory region might and is mapped at different base address) and finally pthread
locks need to be multi-process aware.

Signed-off-by: Grzegorz Milos <Grzegorz.Milos@citrix.com>

2 files changed, 10 insertions, 4 deletions

diff --git a/tools/blktap2/drivers/Makefile b/tools/blktap2/drivers/Makefile
index cd3336ad3c..97f27b56d3 100644
--- a/tools/blktap2/drivers/Makefile
+++ b/tools/blktap2/drivers/Makefile
@@ -15,6 +15,7 @@ CFLAGS    += -fno-strict-aliasing
 CFLAGS    += -I../lib -I../../libxc
 CFLAGS    += -I../include -I../../include
 CFLAGS    += -I $(LIBAIO_DIR)
+CFLAGS    += -I $(MEMSHR_DIR)
 CFLAGS    += -D_GNU_SOURCE
 CFLAGS    += -DUSE_NFS_LOCKS
 
@@ -52,7 +53,9 @@ REMUS-OBJS  += hashtable_utility.o
 $(REMUS-OBJS): CFLAGS += -I$(XEN_XENSTORE)
 
 LIBAIO_DIR = $(XEN_ROOT)/tools/libaio/src
-tapdisk2 tapdisk-stream tapdisk-diff $(QCOW_UTIL): AIOLIBS := $(LIBAIO_DIR)/libaio.a
+MEMSHR_DIR = $(XEN_ROOT)/tools/memshr
+MEMSHRLIBS := $(MEMSHR_DIR)/libmemshr.a
+tapdisk2 tapdisk-stream tapdisk-diff $(QCOW_UTIL): AIOLIBS := $(LIBAIO_DIR)/libaio.a 
 tapdisk-client tapdisk-stream tapdisk-diff $(QCOW_UTIL): CFLAGS  += -I$(LIBAIO_DIR) -I$(XEN_LIBXC)
 
 ifeq ($(VHD_STATIC),y)
@@ -94,13 +97,13 @@ all: $(IBIN) lock-util qcow-util
 
 
 tapdisk2: $(TAP-OBJS-y) $(BLK-OBJS-y) $(MISC-OBJS-y) tapdisk2.c
-	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS) $(AIOLIBS) $(LDFLAGS_img)
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS) $(AIOLIBS) $(MEMSHRLIBS) $(LDFLAGS_img)
 
 tapdisk-client: tapdisk-client.o
 	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS)  $(LDFLAGS_img)
 
 tapdisk-stream tapdisk-diff: %: %.o $(TAP-OBJS-y) $(BLK-OBJS-y)
-	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS) $(AIOLIBS)  $(LDFLAGS_img)
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS) $(AIOLIBS) $(MEMSHRLIBS) $(LDFLAGS_img)
 
 td-util: td.o tapdisk-utils.o tapdisk-log.o $(PORTABLE-OBJS-y)
 	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS)  $(LDFLAGS_img)
@@ -112,7 +115,7 @@ lock-util: lock.c
 qcow-util: img2qcow qcow2raw qcow-create
 
 img2qcow qcow2raw qcow-create: %: %.o $(TAP-OBJS-y) $(BLK-OBJS-y)
-	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS) $(AIOLIBS) $(LDFLAGS_img)
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS) $(AIOLIBS) $(MEMSHRLIBS) $(LDFLAGS_img)
 
 install: all
 	$(INSTALL_DIR) -p $(DESTDIR)$(INST_DIR)
diff --git a/tools/blktap2/drivers/tapdisk-vbd.c b/tools/blktap2/drivers/tapdisk-vbd.c
index e53cede879..07504cf7da 100644
--- a/tools/blktap2/drivers/tapdisk-vbd.c
+++ b/tools/blktap2/drivers/tapdisk-vbd.c
@@ -34,6 +34,7 @@
 #include <libgen.h>
 #include <sys/mman.h>
 #include <sys/ioctl.h>
+#include <memshr.h>
 
 #include "libvhd.h"
 #include "tapdisk-image.h"
@@ -105,6 +106,8 @@ tapdisk_vbd_initialize(int rfd, int wfd, uint16_t uuid)
 	/* default blktap ring completion */
 	vbd->callback = tapdisk_vbd_callback;
 	vbd->argument = vbd;
+    
+    memshr_vbd_initialize();
 
 	INIT_LIST_HEAD(&vbd->driver_stack);
 	INIT_LIST_HEAD(&vbd->images);