Re: [PATCH] Revert "usb: dwc3: gadget: drop unnecessary loop when cleaning up TRBs"

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

On 8/31/2015 10:21 PM, Sergei Shtylyov wrote:

>> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>
>> This reverts commit 8f2c9544aba636134303105ecb164190a39dece4.
>>
>> As it breaks g_ether on my Baytrail FFRD8 device. Everything starts out
>> fine, but after a bit of data has been transferred it just stops
>> flowing.
>>
>> Note that I do get a bunch of these "NOHZ: local_softirq_pending 08"
>> when booting the machine, but I'm not really sure if they're related
>> to this problem.
>>
>> Cc: Felipe Balbi <balbi@ti.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: linux-usb@vger.kernel.org
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> ---
>>   drivers/usb/dwc3/gadget.c | 37 +++++++++++++++++++++----------------
>>   1 file changed, 21 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>> index 333a7c0..9a5de54 100644
>> --- a/drivers/usb/dwc3/gadget.c
>> +++ b/drivers/usb/dwc3/gadget.c
>> @@ -1859,27 +1859,32 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc,
>> struct dwc3_ep *dep,
>>       unsigned int        i;
>>       int            ret;
>>
>> -    req = next_request(&dep->req_queued);
>> -    if (!req) {
>> -        WARN_ON_ONCE(1);
>> -        return 1;
>> -    }
>> -    i = 0;
>>       do {
>> -        slot = req->start_slot + i;
>> -        if ((slot == DWC3_TRB_NUM - 1) &&
>> +        req = next_request(&dep->req_queued);
>> +        if (!req) {
>> +            WARN_ON_ONCE(1);
>> +            return 1;
>> +        }
>> +        i = 0;
>> +        do {
>> +            slot = req->start_slot + i;
>> +            if ((slot == DWC3_TRB_NUM - 1) &&
>>                   usb_endpoint_xfer_isoc(dep->endpoint.desc))
>> -            slot++;
>> -        slot %= DWC3_TRB_NUM;
>> -        trb = &dep->trb_pool[slot];
>> +                slot++;
>> +            slot %= DWC3_TRB_NUM;
>> +            trb = &dep->trb_pool[slot];
>> +
>> +            ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
>> +                    event, status);
>> +            if (ret)
>> +                break;
>> +        }while (++i < req->request.num_mapped_sgs);
>
>     Space needed after }. And this *do {} while* loop seems replaceable with
> *foor* loop...

    Sorry, didn't realize it was a revert. :-/

> [...]

MBR, Sergei