hmem/rocr: fix issue introduced by 43e92bf

43e92bf introduce a build breakage for earlier versions of rocm.
The DMA buf defines were added to handle compatibility, but were
not added around the callback functions. This led to compile error
with older version of the rocm API:

src/hmem_rocr.c:182:36:
  error: ‘hsa_amd_portable_export_dmabuf’ undeclared here (not in a function)
    .hsa_amd_portable_export_dmabuf = hsa_amd_portable_export_dmabuf,

Also made a few changes to clean up warnings and code style.

Signed-off-by: Amir Shehata <shehataa@ornl.gov>

src/hmem_rocr.c

@@ -127,8 +127,10 @@ struct hsa_ops {
 		void *data);
 	hsa_status_t (*hsa_system_get_info)(hsa_system_info_t attribute, 
 					    void* value);
+#if HAVE_HSA_AMD_PORTABLE_EXPORT_DMABUF
 	hsa_status_t (*hsa_amd_portable_export_dmabuf)(const void* ptr, size_t size, 
 						       int* dmabuf, uint64_t* offset);
+#endif
 };
 
 #if ENABLE_ROCR_DLOPEN
@@ -179,7 +181,9 @@ static struct hsa_ops hsa_ops = {
 	.hsa_signal_create = hsa_signal_create,
 	.hsa_signal_destroy = hsa_signal_destroy,
 	.hsa_iterate_agents = hsa_iterate_agents,
+#if HAVE_HSA_AMD_PORTABLE_EXPORT_DMABUF
 	.hsa_amd_portable_export_dmabuf = hsa_amd_portable_export_dmabuf,
+#endif
 	.hsa_system_get_info = hsa_system_get_info,
 };
 
@@ -605,7 +609,7 @@ bool rocr_is_addr_valid(const void *addr, uint64_t *device, uint64_t *flags)
 						 (void *) &hsa_dev_type);
 		if (hsa_ret == HSA_STATUS_SUCCESS) {
 			if (hsa_dev_type == HSA_DEVICE_TYPE_GPU) {
-				//TODO get device pointer/id
+				/* TODO get device pointer/id */
 				if (flags)
 					*flags = FI_HMEM_DEVICE_ONLY;
 				return true;
@@ -1069,13 +1073,15 @@ int rocr_dev_reg_copy_from_hmem(uint64_t handle, void *dest, const void *src,
 static bool rocr_is_dmabuf_supported(void)
 {
 	hsa_status_t hsa_ret;
-	bool use_dmabuf = false, dmabuf_support = false, dmabuf_kernel = false;
+	int use_dmabuf = 0;
+	bool dmabuf_support = false, dmabuf_kernel = false;
 
 	fi_param_get_int(NULL, "hmem_rocr_use_dmabuf", &use_dmabuf);
-	if (!use_dmabuf) goto out;
+	if (!use_dmabuf)
+		goto out;
 
-	// HSA_AMD_SYSTEM_INFO_DMABUF_SUPPORTED = 0x204, we use the number instead of var name
-	// for backward compatibility reasons.
+	/* HSA_AMD_SYSTEM_INFO_DMABUF_SUPPORTED = 0x204, we use the number
+	 * instead of var name for backward compatibility reasons. */
 	hsa_ret = hsa_ops.hsa_system_get_info((hsa_system_info_t) 0x204, &dmabuf_support);
 	if (hsa_ret != HSA_STATUS_SUCCESS) {
 		FI_WARN(&core_prov, FI_LOG_CORE,
@@ -1112,12 +1118,10 @@ static bool rocr_is_dmabuf_supported(void)
 		}
 
 		while (fgets(buf, sizeof(buf), fp) != NULL) {
-			if (strstr(buf, kernel_opt1) != NULL) {
+			if (strstr(buf, kernel_opt1) != NULL)
 				found_opt1 = true;
-			}
-			if (strstr(buf, kernel_opt2) != NULL) {
+			if (strstr(buf, kernel_opt2) != NULL)
 				found_opt2 = true;
-			}
 			if (found_opt1 && found_opt2) {
 				dmabuf_kernel = true;
 				break;
@@ -1134,7 +1138,6 @@ int rocr_hmem_get_dmabuf_fd(const void *addr, uint64_t size, int *dmabuf_fd,
 			     uint64_t *offset)
 {
 	static bool supported = false, checked = false;
-	hsa_status_t hsa_ret;
 
 	if (!checked) {
 		supported = rocr_is_dmabuf_supported();
@@ -1144,7 +1147,11 @@ int rocr_hmem_get_dmabuf_fd(const void *addr, uint64_t size, int *dmabuf_fd,
 		return -FI_EOPNOTSUPP;
 
 #if HAVE_HSA_AMD_PORTABLE_EXPORT_DMABUF
-	// maybe need base addr calculation here? empirically the hsa call here does it internally
+	hsa_status_t hsa_ret;
+
+	/* maybe need base addr calculation here? empirically the hsa call
+	 * here does it internally
+	 */
 	hsa_ret = hsa_ops.hsa_amd_portable_export_dmabuf(addr, size, dmabuf_fd, offset);
 	if (hsa_ret != HSA_STATUS_SUCCESS) {
 		FI_WARN(&core_prov, FI_LOG_CORE,