[SLOF] [PATCH] pci: Reserve free space at the end of bridge windows instead of at the beginning

[Nikunj A Dadhania]

Thomas Huth <thuth at redhat.com> writes:

> On 16.05.2017 08:47, Nikunj A Dadhania wrote:
>> Thomas Huth <thuth at redhat.com> writes:
>> 
>>> This reverts commit e53c2541784fba7951c8aa6ccdbe4412fb03fca6
>>> ("pci-scan: reserve memory for pci-bridge without devices").
>> 
>> The above patch was added for an issue that was reported when an empty
>> pci-bridge was added along with the network adapter, rhel6.5/sles11sp3
>> was not able to get the dhcp address for the network.
>> 
>> The actual problem was while enumerating an empty pci-bridge, stale
>> range value programmed before the bridge probing stayed. Which then
>> caused overlapping pci address allocation.
>> 
>> This does not seem to be an issue any more.
>
> Ok, good to know what the original problem was. Looking at the git
> history, it seems like the main fix for the problem was the commit
> 7cc0b6c5ce87549ba7bc396bfca1018c076a7351 already, and the "reserve
> memory" patch was just the additional sugar

Right

> (since hot-plugging on pci
> bridges is not possible yet, as far as I know)?
>
>>> It's better to reserve the free space at the end of the memory windows
>>> instead (in the pci-bridge-set-[mem|mmio|io]-limit functions), and
>>> with regards to the scarce I/O space, we should also reserve less
>>> I/O memory on each bridge, so we use a limit of 2k (plus alignment)
>>> here now.
>>>
>>> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1443433
>>> Signed-off-by: Thomas Huth <thuth at redhat.com>
>> 
>> Reviewed-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
>
> Thanks!
>
> Any chance that you could commit this while Alexey is away?

Pushed, thanks.

Regards
Nikunj