[Xen-changelog] [xen staging] public/io/ring.h: add FRONT/BACK_RING_ATTACH macros

[patchbot@xxxxxxx]

commit 787bda8eb85b0c6f8b3c81e3586cdf90cd4815f8
Author:     Paul Durrant <pdurrant@xxxxxxxxxx>
AuthorDate: Mon Dec 16 17:36:37 2019 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Dec 16 17:36:37 2019 +0100

    public/io/ring.h: add FRONT/BACK_RING_ATTACH macros
    
    The version of this header present in the Linux source tree has contained
    such macros for some time. These macros, as the names imply, allow front
    or back rings to be set up for existent (rather than freshly created and
    zeroed) shared rings.
    
    This patch is to update this, the canonical version of the header, to
    match the latest definition of these macros in the Linux source.
    
    NOTE: The way the new macros are defined allows the FRONT/BACK_RING_INIT
          macros to be re-defined in terms of them, thereby reducing
          duplication.
    
    Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
    Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/include/public/io/ring.h | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/xen/include/public/io/ring.h b/xen/include/public/io/ring.h
index c5d53e3103..d68615ae2f 100644
--- a/xen/include/public/io/ring.h
+++ b/xen/include/public/io/ring.h
@@ -175,20 +175,24 @@ typedef struct __name##_back_ring __name##_back_ring_t
     (void)memset((_s)->__pad, 0, sizeof((_s)->__pad));                  \
 } while(0)
 
-#define FRONT_RING_INIT(_r, _s, __size) do {                            \
-    (_r)->req_prod_pvt = 0;                                             \
-    (_r)->rsp_cons = 0;                                                 \
+#define FRONT_RING_ATTACH(_r, _s, _i, __size) do {                      \
+    (_r)->req_prod_pvt = (_i);                                          \
+    (_r)->rsp_cons = (_i);                                              \
     (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
     (_r)->sring = (_s);                                                 \
 } while (0)
 
-#define BACK_RING_INIT(_r, _s, __size) do {                             \
-    (_r)->rsp_prod_pvt = 0;                                             \
-    (_r)->req_cons = 0;                                                 \
+#define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size)
+
+#define BACK_RING_ATTACH(_r, _s, _i, __size) do {                       \
+    (_r)->rsp_prod_pvt = (_i);                                          \
+    (_r)->req_cons = (_i);                                              \
     (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
     (_r)->sring = (_s);                                                 \
 } while (0)
 
+#define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size)
+
 /* How big is this ring? */
 #define RING_SIZE(_r)                                                   \
     ((_r)->nr_ents)
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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