Re: [kmods PATCH] linux/igb_uio: allow modules install

[Ferruh Yigit <ferruh.yigit@xilinx.com>]

On 4/12/2022 2:14 PM, Bruce Richardson wrote:
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> 
> 
> For those still using the "igb_uio" kernel module, there may be
> occasions where the module is installed in /lib/modules/$VERSION folder
> rather than being insmod'ed from the build directory. To support this, a
> number of changes are needed to the makefile:
> 
> * Change the "clean" command to a generic wildcard target where that
>    target is just passed through to the top-level kernel makefile. This
>    should allow all standard kernel module targets, including "clean" and
>    "modules_install" to work.

ack

> * To install in /lib/modules, root permissions are needed, so it is
>    likely that users may try installing the module using "sudo". However,
>    under sudo there is often no $PWD environment variable, breaking the
>    build. This can be fixed by changing the environment variable $PWD to
>    the make built-in variable "CURDIR"[1].

It can be possible to use shell PWD:

"make -C $(KSRC)/ M=$$PWD"

or

"
PWD := $(shell pwd)

all:
	make -C $(KSRC)/ M=$(PWD)
"

But '$(CURDIR)' also seems doing the job, so lgtm.

> * As a cleanup, the actual kernel module path is got directly by make
>    from the shell, rather than relying on the shell substitution later
>    when making the recursive make call. This improves things slightly for
>    the user as the full recursive command is visible, with the kernel
>    version appearing in place of `uname -r` in the output.
> 

ack

> [1] While neither PWD nor CURDIR will work correctly in the case where
> one is building outside of the sources directory, this is an edge case,
> and a simple replacement of PWD by CURDIR keeps things simple while
> adding support for "sudo".
> 
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>

Acked-by: Ferruh Yigit <ferruh.yigit@xilinx.com>

> ---
>   linux/igb_uio/Makefile | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/linux/igb_uio/Makefile b/linux/igb_uio/Makefile
> index 09ae5d9..bd2e356 100644
> --- a/linux/igb_uio/Makefile
> +++ b/linux/igb_uio/Makefile
> @@ -1,7 +1,7 @@
> -KSRC ?= /lib/modules/`uname -r`/build
> +KSRC ?= /lib/modules/$(shell uname -r)/build
> 
>   all:
> -       make -C $(KSRC)/ M=$(PWD)
> +       make -C $(KSRC)/ M=$(CURDIR)
> 
> -clean:
> -       make -C $(KSRC)/ M=$(PWD) clean
> +%:
> +       make -C $(KSRC)/ M=$(CURDIR) $@
> --
> 2.32.0
>