kselftests: dmabuf-heaps: Ensure the driver name is null-terminated

Even if a vgem device is configured in, we will skip the import_vgem_fd()
test almost every time.

TAP version 13
1..11
# Te

kselftests: dmabuf-heaps: Ensure the driver name is null-terminated

Even if a vgem device is configured in, we will skip the import_vgem_fd()
test almost every time.

TAP version 13
1..11
# Testing heap: system
# =======================================
# Testing allocation and importing:
ok 1 # SKIP Could not open vgem -1

The problem is that we use the DRM_IOCTL_VERSION ioctl to query the driver
version information but leave the name field a non-null-terminated string.
Terminate it properly to actually test against the vgem device.

While at it, let's check the length of the driver name is exactly 4 bytes
and return early otherwise (in case there is a name like "vgemfoo" that
gets converted to "vgem\0" unexpectedly).

Signed-off-by: Zenghui Yu <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

show more ...