Home
last modified time | relevance | path

Searched hist:"60 f0779862e4ab943810187752c462e85f5fa371" (Results 1 – 1 of 1) sorted by relevance

/openbmc/linux/drivers/virtio/
H A Dvirtio_ring.cdiff 60f0779862e4ab943810187752c462e85f5fa371 Wed Jul 21 09:26:45 CDT 2021 Parav Pandit <parav@nvidia.com> virtio: Improve vq->broken access to avoid any compiler optimization

Currently vq->broken field is read by virtqueue_is_broken() in busy
loop in one context by virtnet_send_command().

vq->broken is set to true in other process context by
virtio_break_device(). Reader and writer are accessing it without any
synchronization. This may lead to a compiler optimization which may
result to optimize reading vq->broken only once.

Hence, force reading vq->broken on each invocation of
virtqueue_is_broken() and also force writing it so that such
update is visible to the readers.

It is a theoretical fix that isn't yet encountered in the field.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Link: https://lore.kernel.org/r/20210721142648.1525924-2-parav@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>