Re: [RFC-v3 3/4] vhost: Add vhost_scsi specific defines

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

On Wed, Jul 18, 2012 at 02:17:05PM -0700, Nicholas A. Bellinger wrote:
> On Wed, 2012-07-18 at 16:05 +0300, Michael S. Tsirkin wrote:
> > On Wed, Jul 18, 2012 at 12:59:31AM +0000, Nicholas A. Bellinger wrote:
> > > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxxxxxxxx>
> > > 
> > > This patch adds the initial vhost_scsi_ioctl() callers for VHOST_SCSI_SET_ENDPOINT
> > > and VHOST_SCSI_CLEAR_ENDPOINT respectively, and also adds struct vhost_vring_target
> > > that is used by tcm_vhost code when locating target ports during qemu setup.
> > > 
> > > Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxxxxxxxxxx>
> > > Cc: Zhi Yong Wu <wuzhy@xxxxxxxxxx>
> > > Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>,
> > > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxxxxxxxx>
> > > ---
> > >  include/linux/vhost.h |    9 +++++++++
> > >  1 files changed, 9 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/include/linux/vhost.h b/include/linux/vhost.h
> > > index e847f1e..33b313b 100644
> > > --- a/include/linux/vhost.h
> > > +++ b/include/linux/vhost.h
> > > @@ -24,7 +24,11 @@ struct vhost_vring_state {
> > >  struct vhost_vring_file {
> > >  	unsigned int index;
> > >  	int fd; /* Pass -1 to unbind from file. */
> > > +};
> > >  
> > > +struct vhost_vring_target {
> > 
> > Can this be renamed vhost_scsi_target?
> 
> Done
> 
> > 
> > > +	unsigned char vhost_wwpn[224];
> > 
> > 224? I am guessing ISCSI_NAME_LEN from include/scsi/iscsi_proto.h?
> > Unfortunately we can't include iscsi_proto.h here as it
> > is not exported to users. But let's add a comment for now.
> > 
> 
> This is actually from target/target_core_base.h:TRANSPORT_IQN_LEN.
> 
> Fixing this up now..
> 
> > > +	unsigned short vhost_tpgt;
> > >  };
> > >  
> > >  struct vhost_vring_addr {
> > > @@ -121,6 +125,11 @@ struct vhost_memory {
> > >   * device.  This can be used to stop the ring (e.g. for migration). */
> > >  #define VHOST_NET_SET_BACKEND _IOW(VHOST_VIRTIO, 0x30, struct vhost_vring_file)
> > >  
> > > +/* VHOST_SCSI specific defines */
> > > +
> > > +#define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct vhost_vring_target)
> > > +#define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct vhost_vring_target)
> > > +
> > >  /* Feature bits */
> > >  /* Log all write descriptors. Can be changed while device is active. */
> > 
> > Can these go into appropriate ifdef CONFIG_TCP_VHOST please?
> > 
> 
> Mmmmm, I don't think we can do that with CONFIG_TCM_VHOST=m, or at least
> not with the following patch
> 
> diff --git a/include/linux/vhost.h b/include/linux/vhost.h
> index 33b313b..e4b1ee3 100644
> --- a/include/linux/vhost.h
> +++ b/include/linux/vhost.h
> @@ -125,10 +126,14 @@ struct vhost_memory {
>   * device.  This can be used to stop the ring (e.g. for migration). */
>  #define VHOST_NET_SET_BACKEND _IOW(VHOST_VIRTIO, 0x30, struct vhost_vring_file)
>  
> +#ifdef CONFIG_TCM_VHOST
> +
>  /* VHOST_SCSI specific defines */
>  
> -#define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct vhost_vring_target)
> -#define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct vhost_vring_target)
> +# define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct vhost_scsi_target)
> +# define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct vhost_scsi_target)
> +
> +#endif
> 
> --
> 
> drivers/vhost/tcm/tcm_vhost.c: In function ‘vhost_scsi_ioctl’:
> drivers/vhost/tcm/tcm_vhost.c:970: error: ‘VHOST_SCSI_SET_ENDPOINT’ undeclared (first use in this function)
> drivers/vhost/tcm/tcm_vhost.c:970: error: (Each undeclared identifier is reported only once
> drivers/vhost/tcm/tcm_vhost.c:970: error: for each function it appears in.)
> drivers/vhost/tcm/tcm_vhost.c:975: error: ‘VHOST_SCSI_CLEAR_ENDPOINT’ undeclared (first use in this function)
> make[3]: *** [drivers/vhost/tcm/tcm_vhost.o] Error 1


Maybe ifdefs only work for booleans? If yes you can probably add a boolean and select it?
What I want to prevent is exposing tcm stuff in the header if it is
configured off. I'll play with it tomorrow.
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