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, 7 insertions, 13 deletions

diff --git a/tools/xenpaging/policy_default.c b/tools/xenpaging/policy_default.c
index a53f5560f6..55a0ae8470 100644
--- a/tools/xenpaging/policy_default.c
+++ b/tools/xenpaging/policy_default.c
@@ -21,8 +21,7 @@
  */
 
 
-#include "bitops.h"
-#include "xc.h"
+#include "xc_bitops.h"
 #include "policy.h"
 
 
@@ -35,26 +34,23 @@ static unsigned int mru_size;
 static unsigned long *bitmap;
 static unsigned long *unconsumed;
 static unsigned long current_gfn;
-static unsigned long bitmap_size;
 static unsigned long max_pages;
 
 
 int policy_init(xenpaging_t *paging)
 {
     int i;
-    int rc;
+    int rc = -ENOMEM;
 
     /* Allocate bitmap for pages not to page out */
-    rc = alloc_bitmap(&bitmap, paging->bitmap_size);
-    if ( rc != 0 )
+    bitmap = bitmap_alloc(paging->domain_info->max_pages);
+    if ( !bitmap )
         goto out;
     /* Allocate bitmap to track unusable pages */
-    rc = alloc_bitmap(&unconsumed, paging->bitmap_size);
-    if ( rc != 0 )
+    unconsumed = bitmap_alloc(paging->domain_info->max_pages);
+    if ( !unconsumed )
         goto out;
 
-    /* record bitmap_size */
-    bitmap_size = paging->bitmap_size;
     max_pages = paging->domain_info->max_pages;
 
     /* Initialise MRU list of paged in pages */
@@ -65,10 +61,7 @@ int policy_init(xenpaging_t *paging)
 
     mru = malloc(sizeof(*mru) * mru_size);
     if ( mru == NULL )
-    {
-        rc = -ENOMEM;
         goto out;
-    }
 
     for ( i = 0; i < mru_size; i++ )
         mru[i] = INVALID_MFN;
@@ -76,6 +69,7 @@ int policy_init(xenpaging_t *paging)
     /* Don't page out page 0 */
     set_bit(0, bitmap);
 
+    rc = 0;
  out:
     return rc;
 }