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Message-ID: <08d5c43f-664c-457f-69a1-c6747bb56637@huawei.com>
Date: Wed, 29 Mar 2023 20:54:25 +0800
From: Yicong Yang <yangyicong@...wei.com>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>
CC: <yangyicong@...ilicon.com>, <mathieu.poirier@...aro.org>,
<suzuki.poulose@....com>, <corbet@....net>,
<linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org>,
<alexander.shishkin@...ux.intel.com>, <helgaas@...nel.org>,
<linux-pci@...r.kernel.org>, <prime.zeng@...wei.com>,
<linuxarm@...wei.com>
Subject: Re: [PATCH 3/4] hwtracing: hisi_ptt: Export available filters through
sysfs
On 2023/3/29 1:02, Jonathan Cameron wrote:
> On Wed, 15 Mar 2023 17:43:15 +0800
> Yicong Yang <yangyicong@...wei.com> wrote:
>
>> From: Yicong Yang <yangyicong@...ilicon.com>
>>
>> The PTT can only filter the traced TLP headers by the Root Ports or the
>> Requester ID of the Endpoint, which are located on the same core of the
>> PTT device. The filter value used is derived from the BDF number of the
>> supported Root Port or the Endpoint. It's not friendly enough for the
>> users since it requires the user to be familiar enough with the platform
>> and calculate the filter value manually.
>>
>> This patch export the available filters through sysfs. Each available
>> filters is presented as an individual file with the name of the BDF
>> number of the related PCIe device. The files are created under
>> $(PTT PMU dir)/available_root_port_filters and
>> $(PTT PMU dir)/available_requester_filters respectively. The filter
>> value can be known by reading the related file.
>>
>> Then the users can easily know the available filters for trace and get
>> the filter values without calculating.
>>
>> Signed-off-by: Yicong Yang <yangyicong@...ilicon.com>
>
> Trivial comments only inline.
>
> With those answered / tidied up.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
>
>
>> diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
>> index 010cdbc3c172..a5cd87edb813 100644
>> --- a/drivers/hwtracing/ptt/hisi_ptt.c
>> +++ b/drivers/hwtracing/ptt/hisi_ptt.c
>
>
>>
>> +
>> +static int hisi_ptt_init_filter_attributes(struct hisi_ptt *hisi_ptt)
>> +{
>> + struct hisi_ptt_filter_desc *filter;
>> + int ret;
>> +
>> + mutex_lock(&hisi_ptt->filter_lock);
>> +
>> + list_for_each_entry(filter, &hisi_ptt->port_filters, list) {
>> + ret = hisi_ptt_create_filter_attr(hisi_ptt, filter);
>> + if (ret)
>> + goto err;
>> + }
>> +
>> + list_for_each_entry(filter, &hisi_ptt->req_filters, list) {
>> + ret = hisi_ptt_create_filter_attr(hisi_ptt, filter);
>> + if (ret)
>> + goto err;
>> + }
>> +
>> + ret = devm_add_action_or_reset(&hisi_ptt->pdev->dev,
>> + hisi_ptt_remove_all_filter_attributes,
>> + hisi_ptt);
>> + if (ret)
>> + goto err;
>> +
>> + hisi_ptt->sysfs_inited = true;
>
> err:
>
>> + mutex_unlock(&hisi_ptt->filter_lock);
>
> return ret;
>
> No need for separate exit block when nothing to do but unlock.
>
ok. will refine here.
>> + return 0;
>> +err:
>> + mutex_unlock(&hisi_ptt->filter_lock);
>> + return ret;
>> +}
>> +
>> static void hisi_ptt_update_filters(struct work_struct *work)
>> {
>> struct delayed_work *delayed_work = to_delayed_work(work);
>> @@ -384,8 +517,28 @@ static void hisi_ptt_update_filters(struct work_struct *work)
>> continue;
>> }
>>
>> + filter->name = kstrdup(pci_name(info.pdev), GFP_KERNEL);
>> + if (!filter->name) {
>> + pci_err(hisi_ptt->pdev, "failed to add filter %s\n",
>> + pci_name(info.pdev));
>> + kfree(filter);
>> + continue;
>> + }
>> +
>> filter->devid = devid;
>> filter->is_port = is_port;
>> +
>> + /*
>> + * If filters' sysfs entries hasn't been initialized, then
>> + * we're still at probe stage and leave it to handled by
>> + * others.
>> + */
>> + if (hisi_ptt->sysfs_inited &&
>
> Can we move this sysfs_inited check earlier? Seems silly to leave a simple check
> like that so late.
>
maybe move it into the hisi_ptt_create_filter_attr()? will have a check.
for here we still need to update filter list even if the hisi_ptt's sysfs is not
initialized yet.
>> + hisi_ptt_create_filter_attr(hisi_ptt, filter)) {
>> + kfree(filter);
>> + continue;
>> + }
>> +
>> list_add_tail(&filter->list, target_list);
>>
>> if (is_port)
>> @@ -394,6 +547,11 @@ static void hisi_ptt_update_filters(struct work_struct *work)
>> list_for_each_entry(filter, target_list, list)
>> if (filter->devid == devid) {
>> list_del(&filter->list);
>> +
>> + if (hisi_ptt->sysfs_inited)
>> + hisi_ptt_remove_filter_attr(hisi_ptt, filter);
>> +
>> + kfree(filter->name);
>> kfree(filter);
>> break;
>> }
>> @@ -486,10 +644,12 @@ static int hisi_ptt_init_filters(struct pci_dev *pdev, void *data)
>> * through the log. Other functions of PTT device are still available.
>> */
>> filter = kzalloc(sizeof(*filter), GFP_KERNEL);
>> - if (!filter) {
>> - pci_err(hisi_ptt->pdev, "failed to add filter %s\n", pci_name(pdev));
>> - return -ENOMEM;
>> - }
>> + if (!filter)
>> + goto err_mem;
>> +
>> + filter->name = kstrdup(pci_name(pdev), GFP_KERNEL);
>> + if (!filter->name)
>> + goto err_name;
>>
>> filter->devid = PCI_DEVID(pdev->bus->number, pdev->devfn);
>>
>> @@ -504,6 +664,11 @@ static int hisi_ptt_init_filters(struct pci_dev *pdev, void *data)
>> }
>>
>> return 0;
>> +err_name:
>> + kfree(filter);
>> +err_mem:
>> + pci_err(hisi_ptt->pdev, "failed to add filter %s\n", pci_name(pdev));
>
> I'd rather see a message for each of the error paths so we have some information on why.
> Original message wasn't great for this obviously and perhaps given they are both allocation
> errors it's not worth splitting them up.
>
ok, will try to split it and make it more verbosely.
Thanks,
Yicong
>> + return -ENOMEM;
>> }
>
>
> .
>
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