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

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

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.

Thanks,
Xiaolong

>
>Igor
>
>On Mon, Dec 2, 2019 at 11:43 AM Ye Xiaolong <xiaolong.ye@intel.com> wrote:
>
>> Hi, Igor
>>
>> Thanks for the feedback.
>>
>> On 12/02, Igor Ryzhov wrote:
>> >Hi Xiaolong,
>> >
>> >Nack from me. It's just an incorrect revert of my fix.
>> >Kernel modules will be installed in wrong directory, just check
>> install_dir
>>
>> Is there any convention that we must install kernel modules to which
>> directory?
>> And what about for cross compilation case?
>>
>> Current issue is that if I specify kernel_dir as one local linux src dir
>> in meson_options.txt,
>> meson build would fail to compile kernel modules while setting
>> RTE_KERNELDIR='/<xxx>/build_dir/target-x86_64_glibc/linux-x86_64/linux-4.19.81/'
>> before make works fine. Is there any subtlety I have missed?
>>
>> Thanks,
>> Xiaolong
>>
>> >parameter in kni/meson.build and igb_uio/meson.build.
>> >
>> >Igor
>> >
>> >On Mon, Dec 2, 2019 at 9:18 AM Xiaolong Ye <xiaolong.ye@intel.com> wrote:
>> >
>> >> kernel_dir option in meson build is equivalent to RTE_KERNELDIR in make
>> >> system, for cross-compilation case, users would specify it as local
>> >> kernel src dir like
>> >>
>> >> /<user local dir>/target-arm_glibc/linux-arm/linux-4.19.81/
>> >>
>> >> Current meson build would fail to compile kernel module if user specify
>> >> kernel_dir as above, this patch fixes this issue.
>> >>
>> >> Fixes: 317832f97c16 ("kernel/linux: fix modules install path")
>> >> Cc: stable@dpdk.org
>> >> Cc: iryzhov@nfware.com
>> >>
>> >> Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
>> >> ---
>> >>  kernel/linux/igb_uio/meson.build | 2 +-
>> >>  kernel/linux/kni/meson.build     | 2 +-
>> >>  kernel/linux/meson.build         | 4 ++--
>> >>  meson_options.txt                | 2 +-
>> >>  4 files changed, 5 insertions(+), 5 deletions(-)
>> >>
>> >> diff --git a/kernel/linux/igb_uio/meson.build
>> >> b/kernel/linux/igb_uio/meson.build
>> >> index fac404f07..e66218dae 100644
>> >> --- a/kernel/linux/igb_uio/meson.build
>> >> +++ b/kernel/linux/igb_uio/meson.build
>> >> @@ -8,7 +8,7 @@ mkfile = custom_target('igb_uio_makefile',
>> >>  custom_target('igb_uio',
>> >>         input: ['igb_uio.c', 'Kbuild'],
>> >>         output: 'igb_uio.ko',
>> >> -       command: ['make', '-C', kernel_dir + '/build',
>> >> +       command: ['make', '-C', kernel_dir,
>> >>                 'M=' + meson.current_build_dir(),
>> >>                 'src=' + meson.current_source_dir(),
>> >>                 'EXTRA_CFLAGS=-I' + meson.current_source_dir() +
>> >> diff --git a/kernel/linux/kni/meson.build b/kernel/linux/kni/meson.build
>> >> index 955eec949..9fce0c16e 100644
>> >> --- a/kernel/linux/kni/meson.build
>> >> +++ b/kernel/linux/kni/meson.build
>> >> @@ -13,7 +13,7 @@ kni_sources = files(
>> >>  custom_target('rte_kni',
>> >>         input: kni_sources,
>> >>         output: 'rte_kni.ko',
>> >> -       command: ['make', '-j4', '-C', kernel_dir + '/build',
>> >> +       command: ['make', '-j4', '-C', kernel_dir,
>> >>                 'M=' + meson.current_build_dir(),
>> >>                 'src=' + meson.current_source_dir(),
>> >>                 'MODULE_CFLAGS=-include ' + meson.source_root() +
>> >> '/config/rte_config.h' +
>> >> diff --git a/kernel/linux/meson.build b/kernel/linux/meson.build
>> >> index 1796cc686..a37c95752 100644
>> >> --- a/kernel/linux/meson.build
>> >> +++ b/kernel/linux/meson.build
>> >> @@ -13,11 +13,11 @@ kernel_dir = get_option('kernel_dir')
>> >>  if kernel_dir == ''
>> >>         # use default path for native builds
>> >>         kernel_version = run_command('uname', '-r').stdout().strip()
>> >> -       kernel_dir = '/lib/modules/' + kernel_version
>> >> +       kernel_dir = '/lib/modules/' + kernel_version + '/build'
>> >>  endif
>> >>
>> >>  # test running make in kernel directory, using "make kernelversion"
>> >> -make_returncode = run_command('make', '-sC', kernel_dir + '/build',
>> >> +make_returncode = run_command('make', '-sC', kernel_dir,
>> >>                 'kernelversion').returncode()
>> >>  if make_returncode != 0
>> >>         warning('Cannot compile kernel modules as requested - are kernel
>> >> headers installed?')
>> >> diff --git a/meson_options.txt b/meson_options.txt
>> >> index bc369d06c..7eba3b720 100644
>> >> --- a/meson_options.txt
>> >> +++ b/meson_options.txt
>> >> @@ -17,7 +17,7 @@ option('ibverbs_link', type: 'combo', choices :
>> >> ['shared', 'dlopen'], value: 'sh
>> >>  option('include_subdir_arch', type: 'string', value: '',
>> >>         description: 'subdirectory where to install arch-dependent
>> >> headers')
>> >>  option('kernel_dir', type: 'string', value: '',
>> >> -       description: 'Path to the kernel for building kernel modules.
>> >> Headers must be in $kernel_dir/build. Modules will be installed in
>> >> $DEST_DIR/$kernel_dir/extra/dpdk.')
>> >> +       description: 'Path to the kernel for building kernel modules.
>> >> Modules will be installed in $DEST_DIR/$kernel_dir/extra/dpdk.')
>> >>  option('lib_musdk_dir', type: 'string', value: '',
>> >>         description: 'path to the MUSDK library installation directory')
>> >>  option('machine', type: 'string', value: 'native',
>> >> --
>> >> 2.17.1
>> >>
>> >>
>>