On Wed, 15 Mar 2023 17:43:14 +0800
Yicong Yang <yangyicong@xxxxxxxxxx> wrote:
> From: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
>
> The PCIe devices supported by the PTT trace can be removed/rescanned by
> hotplug or through sysfs. Add support for dynamically updating the
> available filter list by registering a PCI bus notifier block. Then user
> can always get latest information about available tracing filters and
> driver can block the invalid filters of which related devices no longer
> exist in the system.
>
> Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
> ---
Just a few trivial comments on this.
With those tidied up
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
...
> diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
> index 0a10c7ec46ad..010cdbc3c172 100644
> --- a/drivers/hwtracing/ptt/hisi_ptt.c
> +++ b/drivers/hwtracing/ptt/hisi_ptt.c
> +/*
> + * A PCI bus notifier is used here for dynamically updating the filter
> + * list.
> + */
> +static int hisi_ptt_notifier_call(struct notifier_block *nb, unsigned long action,
> + void *data)
> +{
> + struct hisi_ptt *hisi_ptt = container_of(nb, struct hisi_ptt, hisi_ptt_nb);
> + struct hisi_ptt_filter_update_info info;
> + struct device *dev = data;
> + struct pci_dev *pdev = to_pci_dev(dev);
This local variable doesn't add anything over
info.pdev = to_pci_dev(dev);
> +
> + info.pdev = pdev;
> +
> + switch (action) {
> + case BUS_NOTIFY_ADD_DEVICE:
> + info.is_add = true;
> + break;
> + case BUS_NOTIFY_DEL_DEVICE:
> + info.is_add = false;
> + break;
> + default:
> + return 0;
> + }
> +
> + hisi_ptt_update_fifo_in(hisi_ptt, &info);
> +
> + return 0;
> +}
> +
> diff --git a/drivers/hwtracing/ptt/hisi_ptt.h b/drivers/hwtracing/ptt/hisi_ptt.h
> index 5beb1648c93a..b1ba638fe7ea 100644
> --- a/drivers/hwtracing/ptt/hisi_ptt.h
> +++ b/drivers/hwtracing/ptt/hisi_ptt.h
> @@ -11,12 +11,15 @@
> /**
> * struct hisi_ptt_pmu_buf - Descriptor of the AUX buffer of PTT trace
> * @length: size of the AUX buffer
> @@ -170,10 +188,15 @@ struct hisi_ptt_pmu_buf {
> * @lower_bdf: the lower BDF range of the PCI devices managed by this PTT device
> * @port_filters: the filter list of root ports
> * @req_filters: the filter list of requester ID
> + * @filter_lock: lock to protect the filters
> * @port_mask: port mask of the managed root ports
> + * @work: delayed work for filter updating
> + * @filter_update_lock: spinlock to protect the filter update fifo
> + * @filter_update_fifo: fifo of the filters waiting to update the filter list
> */
> struct hisi_ptt {
> struct hisi_ptt_trace_ctrl trace_ctrl;
> + struct notifier_block hisi_ptt_nb;
Docs update for this one?
> struct hlist_node hotplug_node;
> struct pmu hisi_ptt_pmu;
> void __iomem *iobase;
> @@ -192,7 +215,19 @@ struct hisi_ptt {
> */
> struct list_head port_filters;
> struct list_head req_filters;
> + struct mutex filter_lock;
> u16 port_mask;
> +
> + /*
> + * We use a delayed work here to avoid indefinitely waiting for
> + * the hisi_ptt->mutex which protecting the filter list. The
> + * work will be delayed only if the mutex can not be held,
> + * otherwise no delay will be applied.
> + */
> + struct delayed_work work;
> + spinlock_t filter_update_lock;
> + DECLARE_KFIFO(filter_update_kfifo, struct hisi_ptt_filter_update_info,
> + HISI_PTT_FILTER_UPDATE_FIFO_SIZE);
> };
>
> #define to_hisi_ptt(pmu) container_of(pmu, struct hisi_ptt, hisi_ptt_pmu)
