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SubjectRe: [PATCH V2 5/5] vdpasim: vDPA device simulator
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On 2020/2/11 下午9:52, Jason Gunthorpe wrote:
> On Mon, Feb 10, 2020 at 11:56:08AM +0800, Jason Wang wrote:
>> +
>> +static struct vdpasim *vdpasim_create(void)
>> +{
>> + struct vdpasim *vdpasim;
>> + struct virtio_net_config *config;
>> + struct vdpa_device *vdpa;
>> + struct device *dev;
>> + int ret = -ENOMEM;
>> +
>> + vdpasim = kzalloc(sizeof(*vdpasim), GFP_KERNEL);
>> + if (!vdpasim)
>> + goto err_vdpa_alloc;
>> +
>> + vdpasim->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
>> + if (!vdpasim->buffer)
>> + goto err_buffer_alloc;
>> +
>> + vdpasim->iommu = vhost_iotlb_alloc(2048, 0);
>> + if (!vdpasim->iommu)
>> + goto err_iotlb;
>> +
>> + config = &vdpasim->config;
>> + config->mtu = 1500;
>> + config->status = VIRTIO_NET_S_LINK_UP;
>> + eth_random_addr(config->mac);
>> +
>> + INIT_WORK(&vdpasim->work, vdpasim_work);
>> + spin_lock_init(&vdpasim->lock);
>> +
>> + vdpa = &vdpasim->vdpa;
>> + vdpa->dev.release = vdpasim_release_dev;
> The driver should not provide the release function.
>
> Again the safest model is 'vdpa_alloc_device' which combines the
> kzalloc and the vdpa_init_device() and returns something that is
> error unwound with put_device()
>
> The subsystem owns the release and does the kfree and other cleanup
> like releasing the IDA.


So I think if we agree bus instead of class is used. vDPA bus can
provide a release function in vdpa_alloc_device()?


>
>> + vringh_set_iotlb(&vdpasim->vqs[0].vring, vdpasim->iommu);
>> + vringh_set_iotlb(&vdpasim->vqs[1].vring, vdpasim->iommu);
>> +
>> + dev = &vdpa->dev;
>> + dev->coherent_dma_mask = DMA_BIT_MASK(64);
>> + set_dma_ops(dev, &vdpasim_dma_ops);
>> +
>> + ret = vdpa_init_device(vdpa, &vdpasim_dev->dev, dev,
>> + &vdpasim_net_config_ops);
>> + if (ret)
>> + goto err_init;
>> +
>> + ret = vdpa_register_device(vdpa);
>> + if (ret)
>> + goto err_register;
> See? This error unwind is now all wrong:
>
>> +
>> + return vdpasim;
>> +
>> +err_register:
>> + put_device(&vdpa->dev);
> Double put_device


Yes.


>
>> +err_init:
>> + vhost_iotlb_free(vdpasim->iommu);
>> +err_iotlb:
>> + kfree(vdpasim->buffer);
>> +err_buffer_alloc:
>> + kfree(vdpasim);
> kfree after vdpa_init_device() is incorrect, as the put_device now
> does kfree via release


Ok, will fix.


>
>> +static int __init vdpasim_dev_init(void)
>> +{
>> + struct device *dev;
>> + int ret = 0;
>> +
>> + vdpasim_dev = kzalloc(sizeof(*vdpasim_dev), GFP_KERNEL);
>> + if (!vdpasim_dev)
>> + return -ENOMEM;
>> +
>> + dev = &vdpasim_dev->dev;
>> + dev->release = vdpasim_device_release;
>> + dev_set_name(dev, "%s", VDPASIM_NAME);
>> +
>> + ret = device_register(&vdpasim_dev->dev);
>> + if (ret)
>> + goto err_register;
>> +
>> + if (!vdpasim_create())
>> + goto err_register;
> Wrong error unwind here too


Will fix.

Thanks


>
>> + return 0;
>> +
>> +err_register:
>> + kfree(vdpasim_dev);
>> + vdpasim_dev = NULL;
>> + return ret;
>> +}
> Jason
>

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