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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@amazon.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Paul Durrant authored and Jan Beulich committed
1 parent
ffa21ea530
commit
787bda8eb8
1 file changed
+10
-6
@@ -175,20 +175,24 @@ typedef struct __name##_back_ring __name##_back_ring_t
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(void)memset((_s)->__pad, 0, sizeof((_s)->__pad)); \
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} while(0)
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#define FRONT_RING_INIT(_r, _s, __size) do { \
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(_r)->req_prod_pvt = 0; \
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(_r)->rsp_cons = 0; \
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#define FRONT_RING_ATTACH(_r, _s, _i, __size) do { \
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(_r)->req_prod_pvt = (_i); \
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(_r)->rsp_cons = (_i); \
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(_r)->nr_ents = __RING_SIZE(_s, __size); \
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(_r)->sring = (_s); \
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} while (0)
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#define BACK_RING_INIT(_r, _s, __size) do { \
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(_r)->rsp_prod_pvt = 0; \
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(_r)->req_cons = 0; \
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#define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size)
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#define BACK_RING_ATTACH(_r, _s, _i, __size) do { \
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(_r)->rsp_prod_pvt = (_i); \
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(_r)->req_cons = (_i); \
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(_r)->nr_ents = __RING_SIZE(_s, __size); \
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(_r)->sring = (_s); \
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} while (0)
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#define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size)
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/* How big is this ring? */
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#define RING_SIZE(_r) \
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((_r)->nr_ents)
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