[PATCH] xen/public: fix flexible array definitions

[Juergen Gross <jgross@xxxxxxxx>]

Flexible arrays in public headers can be problematic with some
compilers.

Replace them with arr[XEN_FLEX_ARRAY_DIM] in order to avoid compilation
errors.

This includes arrays defined as "arr[1]", as seen with a recent Linux
kernel [1].

[1]: https://bugzilla.kernel.org/show_bug.cgi?id=217693

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/include/public/io/cameraif.h | 2 +-
 xen/include/public/io/displif.h  | 2 +-
 xen/include/public/io/fsif.h     | 4 ++--
 xen/include/public/io/pvcalls.h  | 2 +-
 xen/include/public/io/ring.h     | 4 ++--
 xen/include/public/io/sndif.h    | 2 +-
 6 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/xen/include/public/io/cameraif.h b/xen/include/public/io/cameraif.h
index 13763abef9..d6c69d6e1c 100644
--- a/xen/include/public/io/cameraif.h
+++ b/xen/include/public/io/cameraif.h
@@ -763,7 +763,7 @@ struct xencamera_buf_create_req {
  */
 struct xencamera_page_directory {
     grant_ref_t gref_dir_next_page;
-    grant_ref_t gref[1]; /* Variable length */
+    grant_ref_t gref[XEN_FLEX_ARRAY_DIM];
 };
 
 /*
diff --git a/xen/include/public/io/displif.h b/xen/include/public/io/displif.h
index 73d0cbdf15..4b9a27e960 100644
--- a/xen/include/public/io/displif.h
+++ b/xen/include/public/io/displif.h
@@ -537,7 +537,7 @@ struct xendispl_dbuf_create_req {
 
 struct xendispl_page_directory {
     grant_ref_t gref_dir_next_page;
-    grant_ref_t gref[1]; /* Variable length */
+    grant_ref_t gref[XEN_FLEX_ARRAY_DIM];
 };
 
 /*
diff --git a/xen/include/public/io/fsif.h b/xen/include/public/io/fsif.h
index ec57850233..0e1fba994a 100644
--- a/xen/include/public/io/fsif.h
+++ b/xen/include/public/io/fsif.h
@@ -40,7 +40,7 @@ struct fsif_read_request {
     int32_t pad;
     uint64_t len;
     uint64_t offset;
-    grant_ref_t grefs[1];  /* Variable length */
+    grant_ref_t grefs[XEN_FLEX_ARRAY_DIM];
 };
 
 struct fsif_write_request {
@@ -48,7 +48,7 @@ struct fsif_write_request {
     int32_t pad;
     uint64_t len;
     uint64_t offset;
-    grant_ref_t grefs[1];  /* Variable length */
+    grant_ref_t grefs[XEN_FLEX_ARRAY_DIM];
 };
 
 struct fsif_stat_request {
diff --git a/xen/include/public/io/pvcalls.h b/xen/include/public/io/pvcalls.h
index 230b0719e3..c8c7602470 100644
--- a/xen/include/public/io/pvcalls.h
+++ b/xen/include/public/io/pvcalls.h
@@ -30,7 +30,7 @@ struct pvcalls_data_intf {
     uint8_t pad2[52];
 
     RING_IDX ring_order;
-    grant_ref_t ref[];
+    grant_ref_t ref[XEN_FLEX_ARRAY_DIM];
 };
 DEFINE_XEN_FLEX_RING(pvcalls);
 
diff --git a/xen/include/public/io/ring.h b/xen/include/public/io/ring.h
index 0cae4367be..fa43396318 100644
--- a/xen/include/public/io/ring.h
+++ b/xen/include/public/io/ring.h
@@ -110,7 +110,7 @@ struct __name##_sring {                                     
            \
         uint8_t pvt_pad[4];                                             \
     } pvt;                                                              \
     uint8_t __pad[44];                                                  \
-    union __name##_sring_entry ring[1]; /* variable-length */           \
+    union __name##_sring_entry ring[XEN_FLEX_ARRAY_DIM];                \
 };                                                                      \
                                                                         \
 /* "Front" end's private variables */                                   \
@@ -479,7 +479,7 @@ struct name##_data_intf {                                   
                  \
     uint8_t pad2[56];                                                         \
                                                                               \
     RING_IDX ring_order;                                                      \
-    grant_ref_t ref[];                                                        \
+    grant_ref_t ref[XEN_FLEX_ARRAY_DIM];                                      \
 };                                                                            \
 DEFINE_XEN_FLEX_RING(name)
 
diff --git a/xen/include/public/io/sndif.h b/xen/include/public/io/sndif.h
index 4234a47c87..32f1fde4d6 100644
--- a/xen/include/public/io/sndif.h
+++ b/xen/include/public/io/sndif.h
@@ -659,7 +659,7 @@ struct xensnd_open_req {
 
 struct xensnd_page_directory {
     grant_ref_t gref_dir_next_page;
-    grant_ref_t gref[1]; /* Variable length */
+    grant_ref_t gref[XEN_FLEX_ARRAY_DIM];
 };
 
 /*
-- 
2.35.3