[PATCH rdma-core v2 3/3] configure: Add check for the presence of DRM headers

[Jianxin Xiong]

Compilation of pyverbs/dmabuf_alloc.c depends on a few DRM headers
that are installed by either the kernel-header or the libdrm package.
The installation is optional and the location is not unique.

Check the presence of the headers at both the standard locations and
any location defined by custom libdrm installation. If the headers
are missing, the dmabuf allocation routines are replaced by stubs that
return suitable error to allow the related tests to skip.

Signed-off-by: Jianxin Xiong <jianxin.xiong at intel.com>
---
 CMakeLists.txt              | 15 +++++++++++++++
 pyverbs/CMakeLists.txt      | 14 ++++++++++++--
 pyverbs/dmabuf_alloc.c      |  8 ++++----
 pyverbs/dmabuf_alloc_stub.c | 39 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 70 insertions(+), 6 deletions(-)
 create mode 100644 pyverbs/dmabuf_alloc_stub.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4113423..95aec11 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -515,6 +515,21 @@ find_package(Systemd)
 include_directories(${SYSTEMD_INCLUDE_DIRS})
 RDMA_DoFixup("${SYSTEMD_FOUND}" "systemd/sd-daemon.h")
 
+# drm headers
+
+# First check the standard locations. The headers could have been installed
+# by either the kernle-headers package or the libdrm package.
+find_path(DRM_INCLUDE_DIRS "drm.h" PATH_SUFFIXES "drm" "libdrm")
+
+# Then check custom installation of libdrm
+if (NOT DRM_INCLUDE_DIRS)
+  pkg_check_modules(DRM libdrm)
+endif()
+
+if (DRM_INCLUDE_DIRS)
+  include_directories(${DRM_INCLUDE_DIRS})
+endif()
+
 #-------------------------
 # Apply fixups
 
diff --git a/pyverbs/CMakeLists.txt b/pyverbs/CMakeLists.txt
index 6fd7625..922253f 100644
--- a/pyverbs/CMakeLists.txt
+++ b/pyverbs/CMakeLists.txt
@@ -13,8 +13,6 @@ rdma_cython_module(pyverbs ""
   cmid.pyx
   cq.pyx
   device.pyx
-  dmabuf.pyx
-  dmabuf_alloc.c
   enums.pyx
   mem_alloc.pyx
   mr.pyx
@@ -25,6 +23,18 @@ rdma_cython_module(pyverbs ""
   xrcd.pyx
 )
 
+if (DRM_INCLUDE_DIRS)
+rdma_cython_module(pyverbs ""
+  dmabuf.pyx
+  dmabuf_alloc.c
+)
+else()
+rdma_cython_module(pyverbs ""
+  dmabuf.pyx
+  dmabuf_alloc_stub.c
+)
+endif()
+
 rdma_python_module(pyverbs
   __init__.py
   pyverbs_error.py
diff --git a/pyverbs/dmabuf_alloc.c b/pyverbs/dmabuf_alloc.c
index 85ffb7a..9978a5b 100644
--- a/pyverbs/dmabuf_alloc.c
+++ b/pyverbs/dmabuf_alloc.c
@@ -9,12 +9,12 @@
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
-#include <drm/drm.h>
-#include <drm/i915_drm.h>
-#include <drm/amdgpu_drm.h>
-#include <drm/radeon_drm.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
+#include <drm.h>
+#include <i915_drm.h>
+#include <amdgpu_drm.h>
+#include <radeon_drm.h>
 #include "dmabuf_alloc.h"
 
 /*
diff --git a/pyverbs/dmabuf_alloc_stub.c b/pyverbs/dmabuf_alloc_stub.c
new file mode 100644
index 0000000..a73a5da
--- /dev/null
+++ b/pyverbs/dmabuf_alloc_stub.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright 2021 Intel Corporation. All rights reserved. See COPYING file
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <errno.h>
+#include "dmabuf_alloc.h"
+
+struct dmabuf *dmabuf_alloc(uint64_t size, int gpu, int gtt)
+{
+	errno = EOPNOTSUPP;
+	return NULL;
+}
+
+void dmabuf_free(struct dmabuf *dmabuf)
+{
+	errno = EOPNOTSUPP;
+}
+
+int dmabuf_get_drm_fd(struct dmabuf *dmabuf)
+{
+	errno = EOPNOTSUPP;
+	return -1;
+}
+
+int dmabuf_get_fd(struct dmabuf *dmabuf)
+{
+	errno = EOPNOTSUPP;
+	return -1;
+}
+
+uint64_t dmabuf_get_offset(struct dmabuf *dmabuf)
+{
+	errno = EOPNOTSUPP;
+	return -1;
+}
+
-- 
1.8.3.1