[PATCH 4.4 9/9] net/ncsi: Improve HNCDSC AEN handler

[Gavin Shan]

On Fri, Oct 21, 2016 at 12:09:37PM +1030, Joel Stanley wrote:
>Hi Gavin,
>
>On Fri, Oct 21, 2016 at 11:17 AM, Gavin Shan <gwshan at linux.vnet.ibm.com> wrote:
>> This improves AEN handler for Host Network Controller Driver Status
>> Change (HNCDSC):
>>
>>    * The channel's lock should be hold when accessing its state.
>>    * Do failover when host driver isn't ready.
>>    * Configure channel when host driver becomes ready.
>>
>> NOTE: The first one isn't applied to the code in dev-4.4.
>
>Can you clarify what you mean here?
>

Joel, dev-4.4 is using old NCSI old where we don't have a spinlock
for NCSI channel. dev-4.7 and upstream code has one to ensure the
consistent read/update on NCSI channel'state. The commit log was
picked from the patch merged to linux.net (branch: "net"), meaning
the commit log corresponds to the code changes for upstream code.

This piece of changes isn't applied to dev-4.4. So I put a note
to clarify it. I'm too lazy and it could be more meaningful actually :)

Thanks,
Gavin

>Cheers,
>
>Joel
>
>>
>> Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
>> ---
>>  net/ncsi/ncsi-aen.c | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/ncsi/ncsi-aen.c b/net/ncsi/ncsi-aen.c
>> index 5bc0873..26ac93d 100644
>> --- a/net/ncsi/ncsi-aen.c
>> +++ b/net/ncsi/ncsi-aen.c
>> @@ -142,8 +142,7 @@ static int ncsi_aen_handler_hncdsc(struct ncsi_dev_priv *ndp,
>>         ncm = &nc->nc_modes[NCSI_MODE_LINK];
>>         hncdsc = (struct ncsi_aen_hncdsc_pkt *)h;
>>         ncm->ncm_data[3] = ntohl(hncdsc->status);
>> -       if (ndp->ndp_active_channel != nc ||
>> -           ncm->ncm_data[3] & 0x1)
>> +       if (ndp->ndp_active_channel != nc)
>>                 return 0;
>>
>>         /* If this channel is the active one and the link doesn't
>> @@ -151,7 +150,8 @@ static int ncsi_aen_handler_hncdsc(struct ncsi_dev_priv *ndp,
>>          * The logic here is exactly similar to what we do when link
>>          * is down on the active channel.
>>          */
>> -       ndp->ndp_flags |= NCSI_DEV_PRIV_FLAG_CHANGE_ACTIVE;
>> +       if (!(ncm->ncm_data[3] & 0x1))
>> +               ndp->ndp_flags |= NCSI_DEV_PRIV_FLAG_CHANGE_ACTIVE;
>>         ncsi_suspend_dev(nd);
>>
>>         return 0;
>> --
>> 2.1.0
>>
>