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authorJ. Bruce Fields <bfields@redhat.com>2010-12-17 13:29:07 -0500
committerJ. Bruce Fields <bfields@redhat.com>2010-12-17 13:29:07 -0500
commitec66ee3797e5848356cf593c6ec7aabf30a00cf1 (patch)
tree7ed5c84cc914644ffa1cd1b6a2b45db53fc224e8 /include/xen/interface/io/ring.h
parent1205065764f2eda3216ebe213143f69891ee3460 (diff)
parentb0c3844d8af6b9f3f18f31e1b0502fbefa2166be (diff)
downloadop-kernel-dev-ec66ee3797e5848356cf593c6ec7aabf30a00cf1.zip
op-kernel-dev-ec66ee3797e5848356cf593c6ec7aabf30a00cf1.tar.gz
Merge commit 'v2.6.37-rc6' into for-2.6.38
Diffstat (limited to 'include/xen/interface/io/ring.h')
-rw-r--r--include/xen/interface/io/ring.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h
index e8cbf43..75271b9 100644
--- a/include/xen/interface/io/ring.h
+++ b/include/xen/interface/io/ring.h
@@ -24,8 +24,15 @@ typedef unsigned int RING_IDX;
* A ring contains as many entries as will fit, rounded down to the nearest
* power of two (so we can mask with (size-1) to loop around).
*/
-#define __RING_SIZE(_s, _sz) \
- (__RD32(((_sz) - (long)&(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
+#define __CONST_RING_SIZE(_s, _sz) \
+ (__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \
+ sizeof(((struct _s##_sring *)0)->ring[0])))
+
+/*
+ * The same for passing in an actual pointer instead of a name tag.
+ */
+#define __RING_SIZE(_s, _sz) \
+ (__RD32(((_sz) - (long)&(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
/*
* Macros to make the correct C datatypes for a new kind of ring.
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