From: Francesco Lavra <francescolavra.fl@gmail.com>
To: Jason Wang <jasowang@redhat.com>,
Zhu Lingshan <lingshan.zhu@intel.com>,
mst@redhat.com, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc: lulu@redhat.com, dan.daly@intel.com, cunming.liang@intel.com
Subject: Re: [PATCH] ifcvf: move IRQ request/free to status change handlers
Date: Mon, 11 May 2020 12:18:29 +0200 [thread overview]
Message-ID: <c1da2054-eb4c-d7dd-ca83-29e85e5cfe90@gmail.com> (raw)
In-Reply-To: <22d9dcdb-e790-0a68-ba41-b9530b2bf9fd@redhat.com>
On 5/11/20 11:26 AM, Jason Wang wrote:
>
> On 2020/5/11 下午3:19, Zhu Lingshan wrote:
>> This commit move IRQ request and free operations from probe()
>> to VIRTIO status change handler to comply with VIRTIO spec.
>>
>> VIRTIO spec 1.1, section 2.1.2 Device Requirements: Device Status Field
>> The device MUST NOT consume buffers or send any used buffer
>> notifications to the driver before DRIVER_OK.
>
>
> My previous explanation might be wrong here. It depends on how you
> implement your hardware, if you hardware guarantee that no interrupt
> will be triggered before DRIVER_OK, then it's fine.
>
> And the main goal for this patch is to allocate the interrupt on demand.
>
>
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>> drivers/vdpa/ifcvf/ifcvf_main.c | 119
>> ++++++++++++++++++++++++----------------
>> 1 file changed, 73 insertions(+), 46 deletions(-)
>>
>> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c
>> b/drivers/vdpa/ifcvf/ifcvf_main.c
>> index abf6a061..4d58bf2 100644
>> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
>> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
>> @@ -28,6 +28,60 @@ static irqreturn_t ifcvf_intr_handler(int irq, void
>> *arg)
>> return IRQ_HANDLED;
>> }
>> +static void ifcvf_free_irq_vectors(void *data)
>> +{
>> + pci_free_irq_vectors(data);
>> +}
>> +
>> +static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
>> +{
>> + struct pci_dev *pdev = adapter->pdev;
>> + struct ifcvf_hw *vf = &adapter->vf;
>> + int i;
>> +
>> +
>> + for (i = 0; i < queues; i++)
>> + devm_free_irq(&pdev->dev, vf->vring[i].irq, &vf->vring[i]);
>> +
>> + ifcvf_free_irq_vectors(pdev);
>> +}
>> +
>> +static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
>> +{
>> + struct pci_dev *pdev = adapter->pdev;
>> + struct ifcvf_hw *vf = &adapter->vf;
>> + int vector, i, ret, irq;
>> +
>> + ret = pci_alloc_irq_vectors(pdev, IFCVF_MAX_INTR,
>> + IFCVF_MAX_INTR, PCI_IRQ_MSIX);
>> + if (ret < 0) {
>> + IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
>> + return ret;
>> + }
>> +
>> + for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) {
>> + snprintf(vf->vring[i].msix_name, 256, "ifcvf[%s]-%d\n",
>> + pci_name(pdev), i);
>> + vector = i + IFCVF_MSI_QUEUE_OFF;
>> + irq = pci_irq_vector(pdev, vector);
>> + ret = devm_request_irq(&pdev->dev, irq,
>> + ifcvf_intr_handler, 0,
>> + vf->vring[i].msix_name,
>> + &vf->vring[i]);
>> + if (ret) {
>> + IFCVF_ERR(pdev,
>> + "Failed to request irq for vq %d\n", i);
>> + ifcvf_free_irq(adapter, i);
>
>
> I'm not sure this unwind is correct. It looks like we should loop and
> call devm_free_irq() for virtqueue [0, i);
That's exactly what the code does: ifcvf_free_irq() contains a (i = 0; i
< queues; i++) loop, and here the function is called with the `queues`
argument set to `i`.
next prev parent reply other threads:[~2020-05-11 10:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 7:19 [PATCH] ifcvf: move IRQ request/free to status change handlers Zhu Lingshan
2020-05-11 9:26 ` Jason Wang
2020-05-11 10:18 ` Francesco Lavra [this message]
2020-05-12 3:41 ` Jason Wang
[not found] ` <0f822630-14ad-e0cd-4171-6213c30f0799@intel.com>
2020-05-12 3:38 ` Jason Wang
2020-05-12 5:51 ` Jason Wang
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