Re: [PATCH v2 2/7] kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED

[David Hildenbrand]

On 09.09.20 09:16, Greg Kroah-Hartman wrote:
> On Tue, Sep 08, 2020 at 10:10:07PM +0200, David Hildenbrand wrote:
>> IORESOURCE_MEM_DRIVER_MANAGED currently uses an unused PnP bit, which is
>> always set to 0 by hardware. This is far from beautiful (and confusing),
>> and the bit only applies to SYSRAM. So let's move it out of the
>> bus-specific (PnP) defined bits.
>>
>> We'll add another SYSRAM specific bit soon. If we ever need more bits for
>> other purposes, we can steal some from "desc", or reshuffle/regroup what we
>> have.
>>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Michal Hocko <mhocko@xxxxxxxx>
>> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
>> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
>> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
>> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
>> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
>> Cc: Baoquan He <bhe@xxxxxxxxxx>
>> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: kexec@xxxxxxxxxxxxxxxxxxx
>> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
>> ---
>>  include/linux/ioport.h | 4 +++-
>>  kernel/kexec_file.c    | 2 +-
>>  mm/memory_hotplug.c    | 4 ++--
>>  3 files changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
>> index 52a91f5fa1a36..d7620d7c941a0 100644
>> --- a/include/linux/ioport.h
>> +++ b/include/linux/ioport.h
>> @@ -58,6 +58,9 @@ struct resource {
>>  #define IORESOURCE_EXT_TYPE_BITS 0x01000000	/* Resource extended types */
>>  #define IORESOURCE_SYSRAM	0x01000000	/* System RAM (modifier) */
>>  
>> +/* IORESOURCE_SYSRAM specific bits. */
>> +#define IORESOURCE_SYSRAM_DRIVER_MANAGED	0x02000000 /* Always detected via a driver. */
>> +
> 
> Can't you use BIT() here?

I could, but this will make it look different to all other IORESOURCE_*
definitions?

If so, we should change all existing definitions - however the ones
spanning multiple bits might turn out rather ugly, like

#define IORESOURCE_TYPE_BITS    0x00001f00

Thoughts? Thanks

> 
> thanks,
> 
> greg k-h
> 


-- 
Thanks,

David / dhildenb