Re: [PATCH 3/3] s390/dma: Allow per device dma ops

[Christian Borntraeger <borntraeger@de.ibm.com>]

Am 03.11.2015 um 13:26 schrieb Cornelia Huck:
> On Tue,  3 Nov 2015 12:54:39 +0100
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> 
>> As virtio-ccw now has dma ops, we can no longer default to the PCI ones.
>> Make use of dev_archdata to keep the dma_ops per device. The pci devices
>> now use that to override the default, and the default is changed to use
>> the noop ops for everything that is not PCI. To compile without PCI
>> support we also have to enable the DMA api with virtio.
> 
> Not only with virtio, but generally, right?

Yes, will update the patch description.
> 
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> Reviewed-by: Joerg Roedel <jroedel@suse.de>
>> Acked-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
>> ---
>>  arch/s390/Kconfig                   | 3 ++-
>>  arch/s390/include/asm/device.h      | 6 +++++-
>>  arch/s390/include/asm/dma-mapping.h | 6 ++++--
>>  arch/s390/pci/pci.c                 | 1 +
>>  arch/s390/pci/pci_dma.c             | 4 ++--
>>  5 files changed, 14 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
>> index 1d57000..04f0e02 100644
>> --- a/arch/s390/Kconfig
>> +++ b/arch/s390/Kconfig
>> @@ -113,6 +113,7 @@ config S390
>>  	select GENERIC_FIND_FIRST_BIT
>>  	select GENERIC_SMP_IDLE_THREAD
>>  	select GENERIC_TIME_VSYSCALL
>> +	select HAS_DMA
>>  	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
>>  	select HAVE_ARCH_AUDITSYSCALL
>>  	select HAVE_ARCH_EARLY_PFN_TO_NID
>> @@ -124,6 +125,7 @@ config S390
>>  	select HAVE_CMPXCHG_DOUBLE
>>  	select HAVE_CMPXCHG_LOCAL
>>  	select HAVE_DEBUG_KMEMLEAK
>> +	select HAVE_DMA_ATTRS
>>  	select HAVE_DYNAMIC_FTRACE
>>  	select HAVE_DYNAMIC_FTRACE_WITH_REGS
>>  	select HAVE_FTRACE_MCOUNT_RECORD
>> @@ -580,7 +582,6 @@ config QDIO
>>
>>  menuconfig PCI
>>  	bool "PCI support"
>> -	select HAVE_DMA_ATTRS
>>  	select PCI_MSI
>>  	help
>>  	  Enable PCI support.
> 
> Hm. Further down in this file, there's
> 
> config HAS_DMA                                                                  
>         def_bool PCI                                                            
>         select HAVE_DMA_API_DEBUG
> 
> Should we maybe select HAVE_DMA_API_DEBUG above, drop the HAS_DMA
> config option and rely on not defining NO_DMA instead?

Hmm, yes. That would simplify things a lot.  Right now we include
lib/Kconfig (which defines HAS_DMA) and define it ourselfes in 
arch/s390/Kconfig. WHoever comes first wins. Adding a select statement
would make this even more complicated.

Andy, I will simply send you a respin of this patch.