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Date:   Mon, 19 Feb 2018 19:33:33 +0100
From:   Daniel Vetter <daniel@ffwll.ch>
To:     Laura Abbott <labbott@redhat.com>
Cc:     Sumit Semwal <sumit.semwal@linaro.org>, devel@driverdev.osuosl.org,
        Todd Kjos <tkjos@android.com>, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, Liam Mark <lmark@codeaurora.org>,
        linux-kselftest@vger.kernel.org, Shuah Khan <shuah@kernel.org>
Subject: Re: [PATCH 2/2] selftests: ion: Add simple test with the vgem driver
Message-ID: <20180219183333.GD22199@phenom.ffwll.local>
Mail-Followup-To: Laura Abbott <labbott@redhat.com>,
        Sumit Semwal <sumit.semwal@linaro.org>, devel@driverdev.osuosl.org,
        Todd Kjos <tkjos@android.com>, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, Liam Mark <lmark@codeaurora.org>,
        linux-kselftest@vger.kernel.org, Shuah Khan <shuah@kernel.org>
References: <20180216012445.17264-1-labbott@redhat.com>
 <20180216012445.17264-3-labbott@redhat.com>
 <20180219153143.GS22199@phenom.ffwll.local>
 <feb5e4c5-b5c2-e235-c952-70c38e185080@redhat.com>
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On Mon, Feb 19, 2018 at 10:18:21AM -0800, Laura Abbott wrote:
> On 02/19/2018 07:31 AM, Daniel Vetter wrote:
> > On Thu, Feb 15, 2018 at 05:24:45PM -0800, Laura Abbott wrote:
> > > Ion is designed to be a framework used by other clients who perform
> > > operations on the buffer. Use the DRM vgem client as a simple consumer.
> > > In conjunction with the dma-buf sync ioctls, this tests the full attach/map
> > > path for the system heap.
> > > 
> > > Signed-off-by: Laura Abbott <labbott@redhat.com>
> > > ---
> > >   tools/testing/selftests/android/ion/Makefile      |   3 +-
> > >   tools/testing/selftests/android/ion/config        |   1 +
> > >   tools/testing/selftests/android/ion/ionmap_test.c | 136 ++++++++++++++++++++++
> > >   3 files changed, 139 insertions(+), 1 deletion(-)
> > >   create mode 100644 tools/testing/selftests/android/ion/ionmap_test.c
> > > 
> > > diff --git a/tools/testing/selftests/android/ion/Makefile b/tools/testing/selftests/android/ion/Makefile
> > > index 96e0c448b39d..d23b6d537d8b 100644
> > > --- a/tools/testing/selftests/android/ion/Makefile
> > > +++ b/tools/testing/selftests/android/ion/Makefile
> > > @@ -2,7 +2,7 @@
> > >   INCLUDEDIR := -I. -I../../../../../drivers/staging/android/uapi/
> > >   CFLAGS := $(CFLAGS) $(INCLUDEDIR) -Wall -O2 -g
> > > -TEST_GEN_FILES := ionapp_export ionapp_import
> > > +TEST_GEN_FILES := ionapp_export ionapp_import ionmap_test
> > >   all: $(TEST_GEN_FILES)
> > > @@ -14,3 +14,4 @@ include ../../lib.mk
> > >   $(OUTPUT)/ionapp_export: ionapp_export.c ipcsocket.c ionutils.c
> > >   $(OUTPUT)/ionapp_import: ionapp_import.c ipcsocket.c ionutils.c
> > > +$(OUTPUT)/ionmap_test: ionmap_test.c ionutils.c
> > > diff --git a/tools/testing/selftests/android/ion/config b/tools/testing/selftests/android/ion/config
> > > index 19db6ca9aa2b..b4ad748a9dd9 100644
> > > --- a/tools/testing/selftests/android/ion/config
> > > +++ b/tools/testing/selftests/android/ion/config
> > > @@ -2,3 +2,4 @@ CONFIG_ANDROID=y
> > >   CONFIG_STAGING=y
> > >   CONFIG_ION=y
> > >   CONFIG_ION_SYSTEM_HEAP=y
> > > +CONFIG_DRM_VGEM=y
> > > diff --git a/tools/testing/selftests/android/ion/ionmap_test.c b/tools/testing/selftests/android/ion/ionmap_test.c
> > > new file mode 100644
> > > index 000000000000..dab36b06b37d
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/android/ion/ionmap_test.c
> > > @@ -0,0 +1,136 @@
> > > +#include <errno.h>
> > > +#include <fcntl.h>
> > > +#include <stdio.h>
> > > +#include <stdint.h>
> > > +#include <string.h>
> > > +#include <unistd.h>
> > > +
> > > +#include <sys/ioctl.h>
> > > +#include <sys/types.h>
> > > +#include <sys/stat.h>
> > > +
> > > +#include <linux/dma-buf.h>
> > > +
> > > +#include <drm/drm.h>
> > > +
> > > +#include "ion.h"
> > > +#include "ionutils.h"
> > > +
> > > +int check_vgem(int fd)
> > > +{
> > > +	drm_version_t version = { 0 };
> > > +	char name[5];
> > > +	int ret;
> > > +
> > > +	version.name_len = 4;
> > > +	version.name = name;
> > > +
> > > +	ret = ioctl(fd, DRM_IOCTL_VERSION, &version);
> > > +	if (ret)
> > > +		return 1;
> > > +
> > > +	return strcmp(name, "vgem");
> > > +}
> > > +
> > > +int open_vgem(void)
> > > +{
> > > +	int i, fd;
> > > +	const char *drmstr = "/dev/dri/card";
> > > +
> > > +	fd = -1;
> > > +	for (i = 0; i < 16; i++) {
> > > +		char name[80];
> > > +
> > > +		sprintf(name, "%s%u", drmstr, i);
> > > +
> > > +		fd = open(name, O_RDWR);
> > > +		if (fd < 0)
> > > +			continue;
> > > +
> > > +		if (check_vgem(fd)) {
> > > +			close(fd);
> > > +			continue;
> > > +		} else {
> > > +			break;
> > > +		}
> > > +
> > > +	}
> > > +	return fd;
> > > +}
> > > +
> > > +int import_vgem_fd(int vgem_fd, int dma_buf_fd, uint32_t *handle)
> > > +{
> > > +	struct drm_prime_handle import_handle = { 0 };
> > > +	int ret;
> > > +
> > > +	import_handle.fd = dma_buf_fd;
> > > +	import_handle.flags = 0;
> > > +	import_handle.handle = 0;
> > > +
> > > +	ret = ioctl(vgem_fd, DRM_IOCTL_PRIME_FD_TO_HANDLE, &import_handle);
> > > +	if (ret == 0)
> > > +		*handle = import_handle.handle;
> > > +	return ret;
> > > +}
> > > +
> > > +void close_handle(int vgem_fd, uint32_t handle)
> > > +{
> > > +	struct drm_gem_close close = { 0 };
> > > +
> > > +	close.handle = handle;
> > > +	ioctl(vgem_fd, DRM_IOCTL_GEM_CLOSE, &close);
> > > +}
> > > +
> > > +int main()
> > > +{
> > > +	int ret, vgem_fd;
> > > +	struct ion_buffer_info info;
> > > +	uint32_t handle = 0;
> > > +	struct dma_buf_sync sync = { 0 };
> > > +
> > > +	info.heap_type = ION_HEAP_TYPE_SYSTEM;
> > > +	info.heap_size = 4096;
> > > +	info.flag_type = ION_FLAG_CACHED;
> > > +
> > > +	ret = ion_export_buffer_fd(&info);
> > > +	if (ret < 0) {
> > > +		printf("ion buffer alloc failed\n");
> > > +		return -1;
> > > +	}
> > > +
> > > +	vgem_fd = open_vgem();
> > > +	if (vgem_fd < 0) {
> > > +		ret = vgem_fd;
> > > +		printf("Failed to open vgem\n");
> > > +		goto out_ion;
> > > +	}
> > > +
> > > +	ret = import_vgem_fd(vgem_fd, info.buffd, &handle);
> > > +
> > > +	if (ret < 0) {
> > > +		printf("Failed to import buffer\n");
> > > +		goto out_vgem;
> > > +	}
> > > +
> > > +	sync.flags = DMA_BUF_SYNC_START | DMA_BUF_SYNC_RW;
> > > +	ret = ioctl(info.buffd, DMA_BUF_IOCTL_SYNC, &sync);
> > > +	if (ret)
> > > +		printf("sync start failed %d\n", errno);
> > > +
> > > +	memset(info.buffer, 0xff, 4096);
> > > +
> > > +	sync.flags = DMA_BUF_SYNC_END | DMA_BUF_SYNC_RW;
> > > +	ret = ioctl(info.buffd, DMA_BUF_IOCTL_SYNC, &sync);
> > > +	if (ret)
> > > +		printf("sync end failed %d\n", errno);
> > 
> > At least in drm we require that userspace auto-restarts all ioctls when
> > they get interrupt. See
> > 
> > https://cgit.freedesktop.org/drm/libdrm/tree/xf86drm.c#n186
> > 
> > not really an issue with vgem (which can't wait for hw or anything else).
> > But good to make sure we don't spread bad copypastas.
> > 
> > Actual use of the ioctls looks all good. With the drmIoctl wrapper added
> > and used this is:
> > 
> > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> 
> Thanks for the review. The reason I didn't use the standard drmIoctl was
> because I didn't want to introduce a dependency on libdrm. I don't see
> an example of another selftest having a dependency on an external
> library.
> 
> Is adding a dependencies on fairly standard but still external userspace
> libraries okay for kernel self tests?

Yeah adding a dependency isn't good, I'd just copypaste a local static
version into the test file. That's good enough, the point isn't to use the
libdrm one, but a wrapper that automatically restarts (every other
userspace for gfx has their own copy of it since it's so trivial).
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch