Re: [Xen-devel] [PATCH 14/25] argo: implement the unregister op

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Christopher Clark [mailto:christopher.w.clark@xxxxxxxxx]
> Sent: 01 December 2018 01:33
> To: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; George Dunlap
> <George.Dunlap@xxxxxxxxxx>; Ian Jackson <Ian.Jackson@xxxxxxxxxx>; Jan
> Beulich <jbeulich@xxxxxxxx>; Julien Grall <julien.grall@xxxxxxx>; Konrad
> Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>; Stefano Stabellini
> <sstabellini@xxxxxxxxxx>; Tim (Xen.org) <tim@xxxxxxx>; Wei Liu
> <wei.liu2@xxxxxxxxxx>; Paul Durrant <Paul.Durrant@xxxxxxxxxx>; Rich
> Persaud <persaur@xxxxxxxxx>; Ross Philipson <ross.philipson@xxxxxxxxx>;
> Eric Chanudet <eric.chanudet@xxxxxxxxx>; James McKenzie
> <voreekf@xxxxxxxxxxxxx>; Jason Andryuk <jandryuk@xxxxxxxxx>; Daniel Smith
> <dpsmith@xxxxxxxxxxxxxxxxxxxx>
> Subject: [PATCH 14/25] argo: implement the unregister op
> 
> Takes a single argument: a handle to the registered ring.
> 
> The ring's entry is removed from the hashtable of registered rings;
> any entries for pending notifications are removed; and the ring is
> unmapped from Xen's address space.
> 
> Signed-off-by: Christopher Clark <christopher.clark6@xxxxxxxxxxxxxx>
> ---
>  xen/common/argo.c         | 62
> +++++++++++++++++++++++++++++++++++++++++++++++
>  xen/include/public/argo.h |  9 +++++++
>  2 files changed, 71 insertions(+)
> 
> diff --git a/xen/common/argo.c b/xen/common/argo.c
> index f4e82cf..387e650 100644
> --- a/xen/common/argo.c
> +++ b/xen/common/argo.c
> @@ -510,6 +510,59 @@ argo_ring_find_info(const struct domain *d, const
> struct argo_ring_id *id)
>  }
> 
>  static long
> +argo_unregister_ring(struct domain *d,
> +                     XEN_GUEST_HANDLE_PARAM(argo_ring_t) ring_hnd)
> +{
> +    struct argo_ring ring;
> +    struct argo_ring_info *ring_info;
> +    int ret = 0;
> +
> +    read_lock(&argo_lock);
> +
> +    do {
> +        if ( !d->argo )
> +        {
> +            ret = -ENODEV;
> +            break;
> +        }
> +
> +        ret = copy_from_guest_errno(&ring, ring_hnd, 1);
> +        if ( ret )
> +            break;
> +
> +        if ( ring.magic != ARGO_RING_MAGIC )
> +        {
> +            argo_dprintk(
> +                "ring.magic(%"PRIx64") != ARGO_RING_MAGIC(%llx),
> EINVAL\n",
> +                ring.magic, ARGO_RING_MAGIC);
> +            ret = -EINVAL;
> +            break;
> +        }
> +
> +        ring.id.addr.domain_id = d->domain_id;
> +
> +        write_lock(&d->argo->lock);
> +
> +        ring_info = argo_ring_find_info(d, &ring.id);
> +        if ( ring_info )
> +            argo_ring_remove_info(d, ring_info);
> +
> +        write_unlock(&d->argo->lock);
> +
> +        if ( !ring_info )
> +        {
> +            argo_dprintk("ENOENT\n");
> +            ret = -ENOENT;
> +            break;
> +        }
> +

Stray blank line?

> +    } while ( 0 );
> +

Again, forward goto style is more conventional.

> +    read_unlock(&argo_lock);
> +    return ret;
> +}
> +
> +static long
>  argo_register_ring(struct domain *d,
>                     XEN_GUEST_HANDLE_PARAM(argo_ring_t) ring_hnd,
>                     XEN_GUEST_HANDLE_PARAM(argo_pfn_t) pfn_hnd, uint32_t
> npage,
> @@ -751,6 +804,15 @@ do_argo_message_op(int cmd,
> XEN_GUEST_HANDLE_PARAM(void) arg1,
>          rc = argo_register_ring(d, ring_hnd, pfn_hnd, npage, fail_exist);
>          break;
>      }
> +    case ARGO_MESSAGE_OP_unregister_ring:
> +    {
> +        XEN_GUEST_HANDLE_PARAM(argo_ring_t) ring_hnd =
> +            guest_handle_cast(arg1, argo_ring_t);
> +        if ( unlikely(!guest_handle_okay(ring_hnd, 1)) )
> +            break;
> +        rc = argo_unregister_ring(d, ring_hnd);
> +        break;
> +    }
>      default:
>          rc = -ENOSYS;
>          break;
> diff --git a/xen/include/public/argo.h b/xen/include/public/argo.h
> index 5ad8e2b..6cf10a8 100644
> --- a/xen/include/public/argo.h
> +++ b/xen/include/public/argo.h
> @@ -116,4 +116,13 @@ struct argo_ring_message_header
>  /* Mask for all defined flags */
>  #define ARGO_REGISTER_FLAG_MASK ARGO_REGISTER_FLAG_FAIL_EXIST
> 
> +/*
> + * ARGO_MESSAGE_OP_unregister_ring
> + *
> + * Unregister a previously-registered ring, ending communication.
> + *
> + * arg1: XEN_GUEST_HANDLE(argo_ring_t)
> + */
> +#define ARGO_MESSAGE_OP_unregister_ring     2
> +
>  #endif
> --
> 2.1.4


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