tools: merge several bitop functions into xc_bitops.h

Bitmaps are used in save/restore, xenpaging and blktap2.  Merge the code into a
private xc_bitops.h file. All users are single threaded, so locking is not an
issue. The array of bits is handled as volatile because the x86 save/restore
code passes the bitmap to the hypervisor which in turn modifies the bitmap.

blktap2 uses a private bitmap. There was a possible overflow in the
bitmap_size() function, the remainder was not considered.

ia64 save/restore uses a bitmap to send the number of vcpus to the host.

x86 save/restore uses a bitmap to track dirty pages. This bitmap is shared with
the hypervisor. An unused function count_bits() was removed and a new
bitmap_size() function is now used.

xenpaging uses 3 private bitmaps to track the gfns which are in paged-out
state.  It had a copy of some Linux bitops.h, which is now obsolete. Also the
BITS_PER_LONG macro was hardcoded to 64 which made it impossible to run 32bit
tools on a 64bit host. Wether this works at all has to be tested, yet.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Committed-by: Ian Jackson <ian.jackson.citrix.com>

1 files changed, 3 insertions, 26 deletions

diff --git a/tools/blktap2/drivers/block-log.c b/tools/blktap2/drivers/block-log.c
index c9612a4b9b..6a63729eca 100644
--- a/tools/blktap2/drivers/block-log.c
+++ b/tools/blktap2/drivers/block-log.c
@@ -47,6 +47,7 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 
+#include "xc_bitops.h"
 #include "log.h"
 #include "tapdisk.h"
 #include "tapdisk-server.h"
@@ -89,31 +90,6 @@ static void ctl_request(event_id_t, char, void *);
 
 /* large flat bitmaps don't scale particularly well either in size or scan
  * time, but they'll do for now */
-#define BITS_PER_LONG (sizeof(unsigned long) * 8)
-#define BITS_TO_LONGS(bits) (((bits)+BITS_PER_LONG-1)/BITS_PER_LONG)
-
-#define BITMAP_ENTRY(_nr, _bmap) ((unsigned long*)(_bmap))[(_nr)/BITS_PER_LONG]
-#define BITMAP_SHIFT(_nr) ((_nr) % BITS_PER_LONG)
-
-static inline int test_bit(int nr, void* bmap)
-{
-  return (BITMAP_ENTRY(nr, bmap) >> BITMAP_SHIFT(nr)) & 1;
-}
-
-static inline void clear_bit(int nr, void* bmap)
-{
-  BITMAP_ENTRY(nr, bmap) &= ~(1UL << BITMAP_SHIFT(nr));
-}
-
-static inline void set_bit(int nr, void* bmap)
-{
-  BITMAP_ENTRY(nr, bmap) |= (1UL << BITMAP_SHIFT(nr));
-}
-
-static inline int bitmap_size(uint64_t sz)
-{
-  return sz >> 3;
-}
 
 static int writelog_create(struct tdlog_state *s)
 {
@@ -123,7 +99,8 @@ static int writelog_create(struct tdlog_state *s)
 
   BDPRINTF("allocating %"PRIu64" bytes for dirty bitmap", bmsize);
 
-  if (!(s->writelog = calloc(bmsize, 1))) {
+  s->writelog = bitmap_alloc(s->size);
+  if (!s->writelog) {
     BWPRINTF("could not allocate dirty bitmap of size %"PRIu64, bmsize);
     return -1;
   }