On Thu, Sep 16, 2021 at 05:40:42PM -0600, Logan Gunthorpe wrote: > Attempt to find the mapping type for P2PDMA pages on the first > DMA map attempt if it has not been done ahead of time. > > Previously, the mapping type was expected to be calculated ahead of > time, but if pages are to come from userspace then there's no > way to ensure the path was checked ahead of time. > > With this change it's no longer invalid to call pci_p2pdma_map_sg() > before the mapping type is calculated so drop the WARN_ON when that > is the case. > > Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Capitalize subject line. > --- > drivers/pci/p2pdma.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 50cdde3e9a8b..1192c465ba6d 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -848,6 +848,7 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider; > struct pci_dev *client; > struct pci_p2pdma *p2pdma; > + int dist; > > if (!provider->p2pdma) > return PCI_P2PDMA_MAP_NOT_SUPPORTED; > @@ -864,6 +865,10 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > type = xa_to_value(xa_load(&p2pdma->map_types, > map_types_idx(client))); > rcu_read_unlock(); > + > + if (type == PCI_P2PDMA_MAP_UNKNOWN) > + return calc_map_type_and_dist(provider, client, &dist, false); > + > return type; > } > > @@ -906,7 +911,6 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, > case PCI_P2PDMA_MAP_BUS_ADDR: > return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents); > default: > - WARN_ON_ONCE(1); > return 0; > } > } > -- > 2.30.2 >
