On Thu, Jan 24, 2019 at 11:13:29AM +0800, Wei Hu (Xavier) wrote:
>
>
> On 2019/1/24 6:40, Jason Gunthorpe wrote:
> > On Sat, Jan 19, 2019 at 11:36:06AM +0800, Wei Hu (Xavier) wrote:
> >
> >> +static int hns_roce_v2_cmd_hw_resetting(struct hns_roce_dev *hr_dev,
> >> + unsigned long instance_stage,
> >> + unsigned long reset_stage)
> >> +{
> >> + struct hns_roce_v2_priv *priv = (struct hns_roce_v2_priv *)hr_dev->priv;
> >> + struct hnae3_handle *handle = priv->handle;
> >> + const struct hnae3_ae_ops *ops = handle->ae_algo->ops;
> >> + unsigned long end;
> >> +
> >> + /* When hardware reset is detected, we should stop sending mailbox&cmq
> >> + * to hardware, and wait until hardware reset finished. If now
> >> + * in .init_instance() function, we should exit with error. If now at
> >> + * HNAE3_INIT_CLIENT stage of soft reset process, we should exit with
> >> + * error, and then HNAE3_INIT_CLIENT related process can rollback the
> >> + * operation like notifing hardware to free resources, HNAE3_INIT_CLIENT
> >> + * related process will exit with error to notify NIC driver to
> >> + * reschedule soft reset process once again.
> >> + */
> >> + end = msecs_to_jiffies(HNS_ROCE_V2_HW_RST_TIMEOUT) + jiffies;
> >> + while (ops->get_hw_reset_stat(handle) && time_before(jiffies, end))
> >> + udelay(1);
> > I thought you were getting rid of these loops?
> Hi, Jason
>
> Upper applications maybe notify driver to issue mailbox or CMD
> commands to hardware, some commands used to cancel resources,
> destory bt/destory cq/unreg mr/destory qp etc. when such
> commands are executed successfully, the hardware engine will
> no longer access some memory registered by the driver.
>
> When reset occurs, it is possible for upper applications notify driver
> to issue mailbox or CMD commands, we need to wait until hardware
> reset finished to ensure that hardware no longer accesses related
> memory.
You should not wait for things using loops like the above.
Jason
