On Wed, Apr 24, 2013 at 11:32:24AM +0800, Asias He wrote:
> Signed-off-by: Asias He <asias@xxxxxxxxxx>
Looks like a good idea to me. I missed this patch
previously, thanks for addressing this.
Some implementation comments below.
> ---
> drivers/vhost/tcm_vhost.c | 16 ++++++++++++++++
> drivers/vhost/tcm_vhost.h | 3 +++
> 2 files changed, 19 insertions(+)
>
> diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
> index def0c57..11fca73 100644
> --- a/drivers/vhost/tcm_vhost.c
> +++ b/drivers/vhost/tcm_vhost.c
> @@ -1204,6 +1204,8 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl,
> u64 __user *featurep = argp;
> u64 features;
> int r, abi_version = VHOST_SCSI_ABI_VERSION;
> + struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT];
> + bool events_missed;
>
> switch (ioctl) {
> case VHOST_SCSI_SET_ENDPOINT:
> @@ -1224,6 +1226,20 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl,
> if (copy_to_user(argp, &abi_version, sizeof abi_version))
> return -EFAULT;
> return 0;
> + case VHOST_SCSI_SET_EVENTS_MISSED:
> + if (copy_from_user(&events_missed, argp, sizeof(events_missed)))
> + return -EFAULT;
This can trigger undefined behaviour because userspace can
make bool have values other than 0 or 1.
So please read an integer here.
This also let you use get_user.
> + mutex_lock(&vq->mutex);
> + vs->vs_events_missed = events_missed;
> + mutex_unlock(&vq->mutex);
> + return 0;
> + case VHOST_SCSI_GET_EVENTS_MISSED:
> + mutex_lock(&vq->mutex);
> + events_missed = vs->vs_events_missed;
> + mutex_unlock(&vq->mutex);
> + if (copy_to_user(argp, &events_missed, sizeof(events_missed)))
> + return -EFAULT;
> + return 0;
> case VHOST_GET_FEATURES:
> features = VHOST_SCSI_FEATURES;
> if (copy_to_user(featurep, &features, sizeof features))
> diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
> index 94e9ee53..b473e25 100644
> --- a/drivers/vhost/tcm_vhost.h
> +++ b/drivers/vhost/tcm_vhost.h
> @@ -123,3 +123,6 @@ struct vhost_scsi_target {
> #define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct vhost_scsi_target)
> /* Changing this breaks userspace. */
> #define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, int)
> +/* Set and get the events missed flag */
> +#define VHOST_SCSI_SET_EVENTS_MISSED _IOW(VHOST_VIRTIO, 0x43, bool)
> +#define VHOST_SCSI_GET_EVENTS_MISSED _IOW(VHOST_VIRTIO, 0x44, bool)
Please don't do bool in user interfaces. No one does. Make it __u32.
> --
> 1.8.1.4
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