Messages in this thread | | | From | Cornelia Huck <> | Subject | Re: [PATCH V4 6/9] virtio-ccw: implement synchronize_cbs() | Date | Wed, 11 May 2022 10:17:22 +0200 |
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On Wed, May 11 2022, Jason Wang <jasowang@redhat.com> wrote:
> On Tue, May 10, 2022 at 7:28 PM Michael S. Tsirkin <mst@redhat.com> wrote: >> >> On Sat, May 07, 2022 at 03:19:51PM +0800, Jason Wang wrote: >> > @@ -1106,6 +1130,7 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev, >> > vcdev->err = -EIO; >> > } >> > virtio_ccw_check_activity(vcdev, activity); >> > + read_lock_irqsave(&vcdev->irq_lock, flags); >> > for_each_set_bit(i, indicators(vcdev), >> > sizeof(*indicators(vcdev)) * BITS_PER_BYTE) { >> > /* The bit clear must happen before the vring kick. */ >> >> Cornelia sent a lockdep trace on this. >> >> Basically I think this gets the irqsave/restore logic wrong. >> It attempts to disable irqs in the handler (which is an interrupt >> anyway). > > The reason I use irqsave/restore is that it can be called from process > context (if I was not wrong), e.g from io_subchannel_quiesce().
io_subchannel_quiesce() should disable interrupts, though? Otherwise, it would be a bug.
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