Messages in this thread Patch in this message | | | Date | Wed, 18 Sep 2019 15:22:42 +0200 | From | Christoph Hellwig <> | Subject | Re: [bug] __blk_mq_run_hw_queue suspicious rcu usage |
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On Tue, Sep 17, 2019 at 06:41:02PM +0000, Lendacky, Thomas wrote: > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > > --- a/drivers/nvme/host/pci.c > > +++ b/drivers/nvme/host/pci.c > > @@ -1613,7 +1613,8 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev) > > dev->admin_tagset.timeout = ADMIN_TIMEOUT; > > dev->admin_tagset.numa_node = dev_to_node(dev->dev); > > dev->admin_tagset.cmd_size = sizeof(struct nvme_iod); > > - dev->admin_tagset.flags = BLK_MQ_F_NO_SCHED; > > + dev->admin_tagset.flags = BLK_MQ_F_NO_SCHED | > > + BLK_MQ_F_BLOCKING; > > I think you want to only set the BLK_MQ_F_BLOCKING if the DMA is required > to be unencrypted. Unfortunately, force_dma_unencrypted() can't be called > from a module. Is there a DMA API that could be called to get that info?
The DMA API must support non-blocking calls, and various drivers rely on that. So we need to provide that even for the SEV case. If the actual blocking can't be made to work we'll need to wire up the DMA pool in kernel/dma/remap.c for it (and probably move it to separate file).
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