On Wed, 20 Dec 2017 12:27:04 +0800
weiping zhang <zwp10758@xxxxxxxxx> wrote:
> As mentioned at drivers/base/core.c:
> /*
> * NOTE: _Never_ directly free @dev after calling this function, even
> * if it returned an error! Always use put_device() to give up the
> * reference initialized in this function instead.
> */
> so we don't free vdev until vdev->vdev.dev.release be called.
>
> Signed-off-by: weiping zhang <zhangweiping@xxxxxxxxxxxxxxx>
> ---
> drivers/misc/mic/vop/vop_main.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/misc/mic/vop/vop_main.c b/drivers/misc/mic/vop/vop_main.c
> index a341938..3633202 100644
> --- a/drivers/misc/mic/vop/vop_main.c
> +++ b/drivers/misc/mic/vop/vop_main.c
> @@ -452,10 +452,12 @@ static irqreturn_t vop_virtio_intr_handler(int irq, void *data)
>
> static void vop_virtio_release_dev(struct device *_d)
> {
> - /*
> - * No need for a release method similar to virtio PCI.
> - * Provide an empty one to avoid getting a warning from core.
> - */
> + struct virtio_device *vdev =
> + container_of(_d, struct virtio_device, dev);
> + struct _vop_vdev *vop_vdev =
> + container_of(vdev, struct _vop_vdev, vdev);
> +
> + kfree(vop_vdev);
> }
>
> /*
> @@ -466,7 +468,7 @@ static int _vop_add_device(struct mic_device_desc __iomem *d,
> unsigned int offset, struct vop_device *vpdev,
> int dnode)
> {
> - struct _vop_vdev *vdev;
> + struct _vop_vdev *vdev, *reg_dev = NULL;
Similarly, not a fan of that pointer variable, but it's fine.
> int ret;
> u8 type = ioread8(&d->type);
>
> @@ -497,6 +499,7 @@ static int _vop_add_device(struct mic_device_desc __iomem *d,
> vdev->c2h_vdev_db = ioread8(&vdev->dc->c2h_vdev_db);
>
> ret = register_virtio_device(&vdev->vdev);
> + reg_dev = vdev;
> if (ret) {
> dev_err(_vop_dev(vdev),
> "Failed to register vop device %u type %u\n",
> @@ -512,7 +515,10 @@ static int _vop_add_device(struct mic_device_desc __iomem *d,
> free_irq:
> vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
> kfree:
> - kfree(vdev);
> + if (reg_dev)
> + put_device(&vdev->vdev.dev);
> + else
> + kfree(vdev);
> return ret;
> }
>
> @@ -568,7 +574,7 @@ static int _vop_remove_device(struct mic_device_desc __iomem *d,
> iowrite8(-1, &dc->h2c_vdev_db);
> if (status & VIRTIO_CONFIG_S_DRIVER_OK)
> wait_for_completion(&vdev->reset_done);
> - kfree(vdev);
> + put_device(&vdev->vdev.dev);
> iowrite8(1, &dc->guest_ack);
> dev_dbg(&vpdev->dev, "%s %d guest_ack %d\n",
> __func__, __LINE__, ioread8(&dc->guest_ack));
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
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