Re: [PATCH v5 3/3] crypto: hisilicon/qm - defining the device isolation strategy

[yekai(A)]

On 2022/7/8 15:35, Greg KH wrote:
> On Fri, Jul 08, 2022 at 03:08:20PM +0800, Kai Ye wrote:
> > Define the device isolation strategy by the device driver. The
> > user configures a frequency value by uacce interface. If the
> > slot reset frequency exceeds the value of setting for a certain
> > period of time, the device will not be available in user space.
> > The time window is one hour. The VF device use the PF device
> > isolation strategy. All the hardware errors are processed by PF
> > driver. This solution can be used for other drivers.
> >
> > Signed-off-by: Kai Ye <yekai13@xxxxxxxxxx>
> > ---
> >  drivers/crypto/hisilicon/qm.c | 163 +++++++++++++++++++++++++++++++---
> >  include/linux/hisi_acc_qm.h   |   9 ++
> >  2 files changed, 160 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
> > index ad83c194d664..8eb3b790a655 100644
> > --- a/drivers/crypto/hisilicon/qm.c
> > +++ b/drivers/crypto/hisilicon/qm.c
> > @@ -417,6 +417,16 @@ struct hisi_qm_resource {
> >  	struct list_head list;
> >  };
> >
> > +/**
> > + * struct qm_hw_err - Structure describing the device errors
> > + * @list: hardware error list
> > + * @timestamp: timestamp when the error occurred
> > + */
> > +struct qm_hw_err {
> > +	struct list_head list;
> > +	unsigned long long timestamp;
> > +};
> > +
> >  struct hisi_qm_hw_ops {
> >  	int (*get_vft)(struct hisi_qm *qm, u32 *base, u32 *number);
> >  	void (*qm_db)(struct hisi_qm *qm, u16 qn,
> > @@ -3410,6 +3420,111 @@ static long hisi_qm_uacce_ioctl(struct uacce_queue *q, unsigned int cmd,
> >  	return 0;
> >  }
> >
> > +/**
> > + * qm_hw_err_isolate() - Try to isolate the uacce device with its VFs
> > + * according to user's configuration of isolation strategy. Warning: this
> > + * API should be called while there the users on this device are suspended
> > + * by slot resetting preparation of PCI AER.
> > + * @qm: the uacce device
> > + */
> > +static int qm_hw_err_isolate(struct hisi_qm *qm)
> > +{
> > +	struct qm_hw_err *err, *tmp, *hw_err;
> > +	struct qm_err_isolate *isolate;
> > +	u32 count = 0;
> > +
> > +	isolate = &qm->isolate_data;
> > +
> > +#define SECONDS_PER_HOUR	3600
> > +
> > +	/* All the hw errs are processed by PF driver */
> > +	if (qm->uacce->is_vf || isolate->is_isolate ||
> > +	    !isolate->hw_err_isolate_hz)
> > +		return 0;
> > +
> > +	hw_err = kzalloc(sizeof(*hw_err), GFP_ATOMIC);
>
> Why atomic?  What lock is held here?

Atomic is not required. So use GFP_KERNEL.
> > +	if (!hw_err)
> > +		return -ENOMEM;
> > +
> > +	mutex_lock(&isolate->isolate_lock);
> > +	hw_err->timestamp = jiffies;
> > +	list_for_each_entry_safe(err, tmp, &isolate->uacce_hw_errs, list) {
> > +		if ((hw_err->timestamp - err->timestamp) / HZ >
> > +		    SECONDS_PER_HOUR) {
>
> No possiblity of wrapping the timestamp?
I do not understand this suggestion, Can you show more detail in this 
suggestion?

> > +			list_del(&err->list);
> > +			kfree(err);
> > +		} else {
> > +			count++;
> > +		}
> > +	}
> > +	list_add(&hw_err->list, &isolate->uacce_hw_errs);
> > +	mutex_unlock(&isolate->isolate_lock);
> > +
> > +	if (count >= isolate->hw_err_isolate_hz)
> > +		isolate->is_isolate = true;
> > +
> > +	return 0;
> > +}
> > +
> > +static void qm_hw_err_destroy(struct hisi_qm *qm)
> > +{
> > +	struct qm_hw_err *err, *tmp;
> > +
> > +	mutex_lock(&qm->isolate_data.isolate_lock);
> > +	list_for_each_entry_safe(err, tmp, &qm->isolate_data.uacce_hw_errs, list) {
> > +		list_del(&err->list);
> > +		kfree(err);
> > +	}
> > +	mutex_unlock(&qm->isolate_data.isolate_lock);
> > +}
> > +
> > +static enum uacce_dev_state hisi_qm_get_isolate_state(struct uacce_device *uacce)
> > +{
> > +	struct hisi_qm *qm = uacce->priv;
> > +	struct hisi_qm *pf_qm;
> > +
> > +	if (uacce->is_vf)
> > +		pf_qm = pci_get_drvdata(pci_physfn(qm->pdev));
> > +	else
> > +		pf_qm = qm;
> > +
> > +	return pf_qm->isolate_data.is_isolate ?
> > +			UACCE_DEV_ISOLATE : UACCE_DEV_NORMAL;
> > +}
> > +
> > +static int hisi_qm_isolate_strategy_write(struct uacce_device *uacce,
> > +					  u32 freq)
> > +{
> > +	struct hisi_qm *qm = uacce->priv;
> > +
> > +	/* Must be set by PF */
> > +	if (uacce->is_vf)
> > +		return -EINVAL;
>
> But the value passed to you is not invalid, something else went wrong.
> Are you sure this is the correct error?
use EPERM instead of EINVAL.
> > +
> > +	if (qm->isolate_data.is_isolate)
> > +		return -EINVAL;
>
> Same here, why is this correct?
use EPERM instead of EINVAL.
> > +
> > +	qm->isolate_data.hw_err_isolate_hz = freq;
>
> No validation of the value passed to you?  It can be anything?
>
> > +
> > +	/* After the policy is updated, need to reset the hardware err list */
> > +	qm_hw_err_destroy(qm);
>
> No error checking?
Due to the process is clean list. So no error checking is required.
> thanks,
>
> greg k-h
> .

Thanks

Kai