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 <[email protected]> --- Changes in v7: - Stop checking req_vq once the broken state is visible, so a waiter woken by freeze/remove does not dereference req_vq after del_vqs() clears it. Changes in v6: - Clear req_vq after del_vqs() and make drain tolerate a NULL queue. Changes in v5: - Reset the device before draining used and unused request tokens. - Use the split broken-marking and post-reset drain helpers. v2->v3: - No change. v3->v4: - Rebased onto v7.1-rc7 and renumbered after the flush error patches. drivers/nvdimm/nd_virtio.c | 5 +++++ drivers/nvdimm/virtio_pmem.c | 34 +++++++++++++++++++++++++++++----- 2 files changed, 34 insertions(+), 5 deletions(-) diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c index a6820300cbe8f..3b8be79a20a0f 100644 --- a/drivers/nvdimm/nd_virtio.c +++ b/drivers/nvdimm/nd_virtio.c @@ -99,6 +99,9 @@ void virtio_pmem_drain(struct virtio_pmem *vpmem) struct virtio_pmem_request *req; unsigned int len; + if (!vpmem->req_vq) + return; + while ((req = virtqueue_get_buf(vpmem->req_vq, &len)) != NULL) { virtio_pmem_clear_inflight(vpmem, req); virtio_pmem_complete_err(req); @@ -218,6 +221,8 @@ static int virtio_pmem_flush(struct nd_region *nd_region) break; } + if (READ_ONCE(vpmem->broken)) + err = -EIO; if (err == -EIO || virtqueue_is_broken(vpmem->req_vq)) virtio_pmem_mark_broken(vpmem); diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c index 36664a5ea25e3..7ee3fb1779f73 100644 --- a/drivers/nvdimm/virtio_pmem.c +++ b/drivers/nvdimm/virtio_pmem.c @@ -17,11 +17,16 @@ static struct virtio_device_id id_table[] = { /* Initialize virt queue */ static int init_vq(struct virtio_pmem *vpmem) { + int err; + /* single vq */ vpmem->req_vq = virtio_find_single_vq(vpmem->vdev, virtio_pmem_host_ack, "flush_queue"); - if (IS_ERR(vpmem->req_vq)) - return PTR_ERR(vpmem->req_vq); + if (IS_ERR(vpmem->req_vq)) { + err = PTR_ERR(vpmem->req_vq); + vpmem->req_vq = NULL; + return err; + } spin_lock_init(&vpmem->pmem_lock); INIT_LIST_HEAD(&vpmem->req_list); @@ -31,6 +36,15 @@ static int init_vq(struct virtio_pmem *vpmem) return 0; }; +static void virtio_pmem_del_vqs(struct virtio_pmem *vpmem) +{ + if (!vpmem->req_vq) + return; + + vpmem->vdev->config->del_vqs(vpmem->vdev); + vpmem->req_vq = NULL; +} + static int virtio_pmem_validate(struct virtio_device *vdev) { struct virtio_shm_region shm_reg; @@ -139,7 +153,7 @@ static int virtio_pmem_probe(struct virtio_device *vdev) virtio_reset_device(vdev); nvdimm_bus_unregister(vpmem->nvdimm_bus); out_vq: - vdev->config->del_vqs(vdev); + virtio_pmem_del_vqs(vpmem); out_wq: destroy_workqueue(vpmem->flush_wq); out_err: @@ -164,18 +178,28 @@ static void virtio_pmem_remove(struct virtio_device *vdev) spin_unlock_irqrestore(&vpmem->pmem_lock, flags); nvdimm_bus_unregister(nvdimm_bus); - vdev->config->del_vqs(vdev); + virtio_pmem_del_vqs(vpmem); destroy_workqueue(vpmem->flush_wq); } static int virtio_pmem_freeze(struct virtio_device *vdev) { struct virtio_pmem *vpmem = vdev->priv; + unsigned long flags; + + spin_lock_irqsave(&vpmem->pmem_lock, flags); + virtio_pmem_mark_broken(vpmem); + spin_unlock_irqrestore(&vpmem->pmem_lock, flags); drain_workqueue(vpmem->flush_wq); - vdev->config->del_vqs(vdev); virtio_reset_device(vdev); + spin_lock_irqsave(&vpmem->pmem_lock, flags); + virtio_pmem_drain(vpmem); + spin_unlock_irqrestore(&vpmem->pmem_lock, flags); + + virtio_pmem_del_vqs(vpmem); + return 0; } -- 2.52.0
