Re: [Xen-devel] [PATCH v7 10/15] argo: implement the notify op

[Christopher Clark <christopher.w.clark@xxxxxxxxx>]

On Thu, Jan 31, 2019 at 8:45 AM Roger Pau Monné <roger.pau@xxxxxxxxxx> wrote:
>
> On Wed, Jan 30, 2019 at 08:28:15PM -0800, Christopher Clark wrote:
> > Queries for data about space availability in registered rings and
> > causes notification to be sent when space has become available.
> >
> > The hypercall op populates a supplied data structure with information about
> > ring state and if insufficient space is currently available in a given ring,
> > the hypervisor will record the domain's expressed interest and notify it
> > when it observes that space has become available.
> >
> > Checks for free space occur when this notify op is invoked, so it may be
> > intentionally invoked with no data structure to populate
> > (ie. a NULL argument) to trigger such a check and consequent notifications.
> >
> > Limit the maximum number of notify requests in a single operation to a
> > simple fixed limit of 256.
> >
> > Signed-off-by: Christopher Clark <christopher.clark6@xxxxxxxxxxxxxx>
> > Tested-by: Chris Patterson <pattersonc@xxxxxxxxxxxx>
>
> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Thanks.

>
> Despite the usage of list_for_each_entry_safe instead of
> list_first_entry_or_null.
>
> > +static void
> > +pending_notify(struct list_head *to_notify)
> > +{
> > +    struct pending_ent *ent, *next;
> > +
> > +    ASSERT(LOCKING_Read_L1);
> > +
> > +    /* Sending signals for all ents in this list, draining until it is 
> > empty. */
> > +    list_for_each_entry_safe(ent, next, to_notify, node)
>
> list_first_entry_or_null would be more suitable here.

ack, applied.

Christopher

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