| Message ID | 20210916234100.122368-3-logang@deltatee.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | Userspace P2PDMA with O_DIRECT NVMe devices | expand |
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@deltatee.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> 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 >
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; } }
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@deltatee.com> --- drivers/pci/p2pdma.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)