[PATCH 10/15] powerpc/powernv/pci: Refactor pnv_ioda_alloc_pe()

[Alexey Kardashevskiy]

On 15/07/2020 12:53, Oliver O'Halloran wrote:
> On Wed, Jul 15, 2020 at 12:29 PM Alexey Kardashevskiy <aik at ozlabs.ru> wrote:
>>
>>
>>
>> On 10/07/2020 15:23, Oliver O'Halloran wrote:
>>> Rework the PE allocation logic to allow allocating blocks of PEs rather
>>> than individually. We'll use this to allocate contigious blocks of PEs for
>>> the SR-IOVs.
>>
>> The patch does not do just this, it also adds missing mutexes (which is
>> good) but still misses them in pnv_pci_sriov_disable() and
>> pnv_pci_ioda_pe_dump().
> 
> The current implementation doesn't need the mutex because alloc,
> reserve and free all use atomic bit ops.

Ah, ok.

> The mutex has been there
> forever with nothing actually using it, but with the change we need to
> prevent modifications to the bitmap while alloc() is scanning it. I
> probably should have mentioned that in the commit message.

but bitmap_clear() (from pnv_pci_sriov_disable()) is not atomic. It
probably does not matter as the next patch gets rid of it anyway.


-- 
Alexey