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Subject: Re: [PATCH 2/2] selftests: ion: Add simple test with the vgem driver
To:     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>
From:   Laura Abbott <labbott@redhat.com>
Message-ID: <feb5e4c5-b5c2-e235-c952-70c38e185080@redhat.com>
Date:   Mon, 19 Feb 2018 10:18:21 -0800
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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?

Thanks,
Laura