Re: [dpdk-dev] [PATCH] kernel/linux: fix kernel dir for meson

[Ye Xiaolong <xiaolong.ye@intel.com>]

On 12/02, Bruce Richardson wrote:
>On Mon, Dec 02, 2019 at 07:34:54PM +0800, Ye Xiaolong wrote:
>> On 12/02, Igor Ryzhov wrote:
>> >We should at least install it into /lib/modules/kernel-version. For
>> >convenience, dpdk modules are installed into
>> >/lib/modules/kernel-version/extra/dpdk.
>> >In the cross-compilation case, you can use DEST_DIR to set some prefix.
>> >
>> >I don't really see the issue here. The description clearly says that
>> >headers must be in $kernel_dir/build which is usually a symlink
>> >to /usr/src/linux-headers-kernel-version.
>> >Just set kernel_dir correctly and there won't be compilation failure.
>> 
>> I think for cross-compilation case, user should be allowed to specify any kernel
>> src dir (it doesn't have to be /lib/modules/kernel-version) in his local system 
>> as kernel_dir that doesn't contain the build dir, in this case, current meson
>> build will skip kernel module compilation.
>> 
>
>I don't think we can take this change as the default, since the previous
>fix was put in for good reason.
>
>However, perhaps we can attempt to support both, using the checks below for
>"make kernelversion" in kernel/linux/meson.build. We can attempt using the
>directory with /build (as now) and then if that fails attempt without it (or
>vice versa).

After a second thought, I think it'd be better that we unify the meaning of
kernel_dir for both cases, it should be aligned with make's RTE_KERNELDIR 
variable that specify the directory contains kernel src code (or header), then
we don't need to distinguish these 2 cases in check (make kernelversion) phase,
we just need to assign different install dirs,

For normal case:

kernel_dir=/lib/modules/<kernel_version>/build
install_dir=/lib/modules/<kernel_version>/extra/dpdk

For cross compilation case:

kernel_dir=<Any kernel src dir specified by user>
install_dir=<Any kernel src dir specified by user>/extra/dpdk

What do you think (I've sent v2 according to above description)?

Thanks,
Xiaolong

>
>/Bruce