[SOLARIS] Provide non-gcc-specific defn. of RING_HAS_UNCONSUMED_REQUESTS.

From: Mark Johnson <mark.johnson@sun.com>
Signed-off-by: Keir Fraser <keir@xensource.com>

diff --git a/xen/include/public/io/ring.h b/xen/include/public/io/ring.h
index 6b56dc3211897992b5c993f729414b955096f0bd..d427ba6679ac28c4b7f961f26215ce9c58cb409b 100644 (file)
--- a/xen/include/public/io/ring.h
+++ b/xen/include/public/io/ring.h
@@ -152,7 +152,7 @@ typedef struct __name##_back_ring __name##_back_ring_t
     ((_r)->nr_ents)
 
 /* Number of free requests (for use on front side only). */
-#define RING_FREE_REQUESTS(_r)                                         \
+#define RING_FREE_REQUESTS(_r)                                          \
     (RING_SIZE(_r) - ((_r)->req_prod_pvt - (_r)->rsp_cons))
 
 /* Test if there is an empty slot available on the front ring.
@@ -165,13 +165,21 @@ typedef struct __name##_back_ring __name##_back_ring_t
 #define RING_HAS_UNCONSUMED_RESPONSES(_r)                               \
     ((_r)->sring->rsp_prod - (_r)->rsp_cons)
 
+#ifdef __GNUC__
+#define RING_HAS_UNCONSUMED_REQUESTS(_r) ({                             \
+    unsigned int req = (_r)->sring->req_prod - (_r)->req_cons;          \
+    unsigned int rsp = RING_SIZE(_r) -                                  \
+        ((_r)->req_cons - (_r)->rsp_prod_pvt);                          \
+    req < rsp ? req : rsp;                                              \
+})
+#else
+/* Same as above, but without the nice GCC ({ ... }) syntax. */
 #define RING_HAS_UNCONSUMED_REQUESTS(_r)                                \
-    ({                                                                 \
-       unsigned int req = (_r)->sring->req_prod - (_r)->req_cons;      \
-       unsigned int rsp = RING_SIZE(_r) -                              \
-                          ((_r)->req_cons - (_r)->rsp_prod_pvt);       \
-       req < rsp ? req : rsp;                                          \
-    })
+    ((((_r)->sring->req_prod - (_r)->req_cons) <                        \
+      (RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt))) ?        \
+     ((_r)->sring->req_prod - (_r)->req_cons) :                         \
+     (RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt)))
+#endif
 
 /* Direct access to individual ring elements, by index. */
 #define RING_GET_REQUEST(_r, _idx)                                      \