diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-01-11 15:10:08 +1100 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-01-11 15:10:08 +1100 |
| commit | eed0ba0b4ab2d1668588219a8efa81bf8636a12d (patch) | |
| tree | f5aa3c732e7830a1b24e6071f8bed0f799881187 /include/xen/interface/io/ring.h | |
| parent | 98b14d6b290d96b24ae993ceaccc59b2aa4b130c (diff) | |
| parent | c9de9333f5a860cab82052bce6ac28bcac9b2c26 (diff) | |
Merge remote branch 'gcl/next' into next
Diffstat (limited to 'include/xen/interface/io/ring.h')
| -rw-r--r-- | include/xen/interface/io/ring.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h index e8cbf431c8c..75271b9a8f6 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. |