Re: [Xen-devel] [PATCH v3 15/18] xen/pvcalls: implement the ioworker functions

[Juergen Gross <jgross@xxxxxxxx>]

On 02/06/17 21:31, Stefano Stabellini wrote:
> We have one ioworker per socket. Each ioworker goes through the list of
> outstanding read/write requests. Once all requests have been dealt with,
> it returns.
> 
> We use one atomic counter per socket for "read" operations and one
> for "write" operations to keep track of the reads/writes to do.
> 
> We also use one atomic counter ("io") per ioworker to keep track of how
> many outstanding requests we have in total assigned to the ioworker. The
> ioworker finishes when there are none.
> 
> Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
> CC: boris.ostrovsky@xxxxxxxxxx
> CC: jgross@xxxxxxxx
> ---
>  drivers/xen/pvcalls-back.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
> index 6afe7a0..0283d49 100644
> --- a/drivers/xen/pvcalls-back.c
> +++ b/drivers/xen/pvcalls-back.c
> @@ -99,8 +99,35 @@ static int pvcalls_back_release_active(struct 
> xenbus_device *dev,
>                                      struct pvcalls_fedata *priv,
>                                      struct sock_mapping *map);
>  
> +static void pvcalls_conn_back_read(unsigned long opaque)

Why not void *opaque? You could drop the cast below then.


Juergen

> +{
> +}
> +
> +static int pvcalls_conn_back_write(struct sock_mapping *map)
> +{
> +     return 0;
> +}
> +
>  static void pvcalls_back_ioworker(struct work_struct *work)
>  {
> +     struct pvcalls_ioworker *ioworker = container_of(work,
> +             struct pvcalls_ioworker, register_work);
> +     struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
> +             ioworker);
> +
> +     while (atomic_read(&map->io) > 0) {
> +             if (atomic_read(&map->release) > 0) {
> +                     atomic_set(&map->release, 0);
> +                     return;
> +             }
> +
> +             if (atomic_read(&map->read) > 0)
> +                     pvcalls_conn_back_read((unsigned long)map);
> +             if (atomic_read(&map->write) > 0)
> +                     pvcalls_conn_back_write(map);
> +
> +             atomic_dec(&map->io);
> +     }
>  }
>  
>  static int pvcalls_back_socket(struct xenbus_device *dev,
> 


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