Add explicit sync call to ion library

Bug: 6854979
Change-Id: I535d55af897eeb4ed707b5da54f3fbf36afa452c
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>

include/ion/ion.h

@@ -31,6 +31,7 @@ int ion_alloc(int fd, size_t len, size_t align, unsigned int heap_mask,
 	      unsigned int flags, struct ion_handle **handle);
 int ion_alloc_fd(int fd, size_t len, size_t align, unsigned int heap_mask,
 		 unsigned int flags, int *handle_fd);
+int ion_sync_fd(int fd, int handle_fd);
 int ion_free(int fd, struct ion_handle *handle);
 int ion_map(int fd, struct ion_handle *handle, size_t length, int prot,
             int flags, off_t offset, unsigned char **ptr, int *map_fd);

libion/ion.c

@@ -146,3 +146,11 @@ int ion_import(int fd, int share_fd, struct ion_handle **handle)
         *handle = data.handle;
         return ret;
 }
+
+int ion_sync_fd(int fd, int handle_fd)
+{
+    struct ion_fd_data data = {
+        .fd = handle_fd,
+    };
+    return ion_ioctl(fd, ION_IOC_SYNC, &data);
+}