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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-01-18 08:04:23 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-01-18 08:18:16 +0100 |
| commit | 2da80b57c69a2a5ae0e16dead8cdbfab46f970bc (patch) | |
| tree | 402529def53a1b32066493f5581c3e1810d11a1d /include/xen | |
| parent | 2d7f3bdb2cf6656386cb9ca1b02dd6df66fb05e8 (diff) | |
| parent | 1df59b8497f47495e873c23abd6d3d290c730505 (diff) | |
| download | linux-2da80b57c69a2a5ae0e16dead8cdbfab46f970bc.tar.bz2 | |
Merge remote-tracking branch 'airlied/drm-next' into drm-intel-next-queued
Pull in Dave's drm-next pull request to have a clean base for 4.6.
Also, we need the various atomic state extensions Maarten recently
created.
Conflicts are just adjacent changes that all resolve to nothing in git
diff.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Diffstat (limited to 'include/xen')
| -rw-r--r-- | include/xen/interface/io/ring.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h index 7d28aff605c7..7dc685b4057d 100644 --- a/include/xen/interface/io/ring.h +++ b/include/xen/interface/io/ring.h @@ -181,6 +181,20 @@ struct __name##_back_ring { \ #define RING_GET_REQUEST(_r, _idx) \ (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req)) +/* + * Get a local copy of a request. + * + * Use this in preference to RING_GET_REQUEST() so all processing is + * done on a local copy that cannot be modified by the other end. + * + * Note that https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 may cause this + * to be ineffective where _req is a struct which consists of only bitfields. + */ +#define RING_COPY_REQUEST(_r, _idx, _req) do { \ + /* Use volatile to force the copy into _req. */ \ + *(_req) = *(volatile typeof(_req))RING_GET_REQUEST(_r, _idx); \ +} while (0) + #define RING_GET_RESPONSE(_r, _idx) \ (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp)) |