nvdimm: virtio_pmem: drain requests in freeze

virtio_pmem_freeze() currently deletes virtqueues and resets the device
without waking threads waiting for a virtqueue descriptor or a host
completion.

Mark the request virtqueue broken before reset. This makes new submissions
fail fast and lets -ENOSPC waiters leave the wait list. Reset the device
before draining used and unused request tokens, then delete the virtqueues.
This wakes waiters with -EIO. It also keeps the detach call on a quiesced
device.

Clear req_vq after del_vqs(). Make drain tolerate a NULL queue so remove
after freeze does not dereference a stale virtqueue pointer. Also make
virtio_pmem_flush() stop checking req_vq once the broken state is visible.
A waiter woken by freeze/remove can resume after del_vqs() has cleared
req_vq.

Signed-off-by: Li Chen <me@linux.beauty>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260630092338.2094628-13-me@linux.beauty>

0 files changed, 0 insertions, 0 deletions