Re: [PATCH v3 1/3] update-linux-headers: Include const.h

[Eric Farman <farman@linux.ibm.com>]

On 1/6/21 2:03 PM, Peter Xu wrote:
> On Mon, Jan 04, 2021 at 09:20:55PM +0100, Eric Farman wrote:
>> Kernel commit a85cbe6159ff ("uapi: move constants from
>> <linux/kernel.h> to <linux/const.h>") breaks our script
>> because of the unrecognized include. Let's add that to
>> our processing.
>>
>> Signed-off-by: Eric Farman <farman@linux.ibm.com>
>> ---
>>   scripts/update-linux-headers.sh | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/scripts/update-linux-headers.sh b/scripts/update-linux-headers.sh
>> index 9efbaf2f84..fa6f2b6272 100755
>> --- a/scripts/update-linux-headers.sh
>> +++ b/scripts/update-linux-headers.sh
>> @@ -41,6 +41,7 @@ cp_portable() {
>>                                        -e 'pvrdma_verbs' \
>>                                        -e 'drm.h' \
>>                                        -e 'limits' \
>> +                                     -e 'linux/const' \
>>                                        -e 'linux/kernel' \
>>                                        -e 'linux/sysinfo' \
>>                                        -e 'asm-generic/kvm_para' \
>> @@ -190,7 +191,9 @@ for i in "$tmpdir"/include/linux/*virtio*.h \
>>            "$tmpdir/include/linux/input.h" \
>>            "$tmpdir/include/linux/input-event-codes.h" \
>>            "$tmpdir/include/linux/pci_regs.h" \
>> -         "$tmpdir/include/linux/ethtool.h" "$tmpdir/include/linux/kernel.h" \
>> +         "$tmpdir/include/linux/ethtool.h" \
>> +         "$tmpdir/include/linux/const.h" \
>> +         "$tmpdir/include/linux/kernel.h" \
>>            "$tmpdir/include/linux/vhost_types.h" \
>>            "$tmpdir/include/linux/sysinfo.h"; do
>>       cp_portable "$i" "$output/include/standard-headers/linux"
>> -- 
>> 2.17.1
> 
> So I think I came to the same change when trying to update the headers. :)
> 
> Reviewed-by: Peter Xu <peterx@redhat.com>

Thank you!  :)

> 
> Could I ask why the const.h is installed into include/standard-headers/linux
> rather than linux-headers/linux?  When I was working on my version I failed to
> figure out the difference.

Considering the main difference is whether the header file is copied 
directly or edited with a bunch of substitutions, and const.h doesn't 
get modified by those substitutions, I suppose it could go in 
linux-headers itself. But I opted to just keep it near its friends 
(ethtool.h and kernel.h both include const.h, and end up including 
if_ether.h, sysinfo.h, and types.h) in include/standard-headers.

> 
> One answer is ethtool.h is there which included const.h, but I guess that's not
> the real one.
> 
> Thanks,
>