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

From: Juergen Gross
Date: Tue Jun 13 2017 - 03:51:52 EST


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,
>