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

[Thomas Huth]

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 (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?

 Thomas