From: linux-hyperv-owner@xxxxxxxxxxxxxxx <linux-hyperv-owner@xxxxxxxxxxxxxxx> On Behalf
Of Wei Liu. Sent: Friday, June 26, 2020 9:20 AM
> > static int __vmbus_open(struct vmbus_channel *newchannel,
> > void *userdata, u32 userdatalen,
> > void (*onchannelcallback)(void *context), void *context)
> > @@ -122,6 +186,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
> > u32 send_pages, recv_pages;
> > unsigned long flags;
> > int err;
> > + int rqstor;
> >
> > if (userdatalen > MAX_USER_DEFINED_BYTES)
> > return -EINVAL;
> > @@ -132,6 +197,14 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
> > if (newchannel->state != CHANNEL_OPEN_STATE)
> > return -EINVAL;
> >
> > + /* Create and init requestor */
> > + if (newchannel->rqstor_size) {
> > + rqstor = vmbus_alloc_requestor(&newchannel->requestor,
> > + newchannel->rqstor_size);
>
> You can simply use err here to store the return value or even get rid of
> rqstor by doing
Right. I will do that.
> > @@ -937,3 +1014,75 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void
> *buffer,
> > buffer_actual_len, requestid, true);
> > }
> > EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
> > +
> > +/*
> > + * vmbus_next_request_id - Returns a new request id. It is also
> > + * the index at which the guest memory address is stored.
> > + * Uses a spin lock to avoid race conditions.
> > + * @rqstor: Pointer to the requestor struct
> > + * @rqst_add: Guest memory address to be stored in the array
> > + */
> > +u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr)
> > +{
> > + unsigned long flags;
> > + u64 current_id;
> > +
> > + spin_lock_irqsave(&rqstor->req_lock, flags);
>
> Do you really need the irqsave variant here? I.e. is there really a
> chance this code is reachable from an interrupt handler?
Other VMBus drivers will also need to use this functionality, and
some of them will be called with interrupts disabled. So, I think
we should keep the irqsave variant here.
Andres.
