On Tue, Jan 29, 2019 at 12:47 PM jglisse@redhat.com wrote:
From: Jérôme Glisse jglisse@redhat.com
device_test_p2p() return true if two devices can peer to peer to each other. We add a generic function as different inter-connect can support peer to peer and we want to genericaly test this no matter what the inter-connect might be. However this version only support PCIE for now.
What about something like these patches: https://cgit.freedesktop.org/~deathsimple/linux/commit/?h=p2p&id=4fab9ff... https://cgit.freedesktop.org/~deathsimple/linux/commit/?h=p2p&id=f90b12d... They are a bit more thorough.
Alex
Signed-off-by: Jérôme Glisse jglisse@redhat.com Cc: Logan Gunthorpe logang@deltatee.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Rafael J. Wysocki rafael@kernel.org Cc: Bjorn Helgaas bhelgaas@google.com Cc: Christian Koenig christian.koenig@amd.com Cc: Felix Kuehling Felix.Kuehling@amd.com Cc: Jason Gunthorpe jgg@mellanox.com Cc: linux-kernel@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: Christoph Hellwig hch@lst.de Cc: Marek Szyprowski m.szyprowski@samsung.com Cc: Robin Murphy robin.murphy@arm.com Cc: Joerg Roedel jroedel@suse.de Cc: iommu@lists.linux-foundation.org
drivers/pci/p2pdma.c | 27 +++++++++++++++++++++++++++ include/linux/pci-p2pdma.h | 6 ++++++ 2 files changed, 33 insertions(+)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index c52298d76e64..620ac60babb5 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -797,3 +797,30 @@ ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, return sprintf(page, "%s\n", pci_name(p2p_dev)); } EXPORT_SYMBOL_GPL(pci_p2pdma_enable_show);
+bool pci_test_p2p(struct device *devA, struct device *devB) +{
struct pci_dev *pciA, *pciB;
bool ret;
int tmp;
/*
* For now we only support PCIE peer to peer but other inter-connect
* can be added.
*/
pciA = find_parent_pci_dev(devA);
pciB = find_parent_pci_dev(devB);
if (pciA == NULL || pciB == NULL) {
ret = false;
goto out;
}
tmp = upstream_bridge_distance(pciA, pciB, NULL);
ret = tmp < 0 ? false : true;
+out:
pci_dev_put(pciB);
pci_dev_put(pciA);
return false;
+} +EXPORT_SYMBOL_GPL(pci_test_p2p); diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index bca9bc3e5be7..7671cc499a08 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -36,6 +36,7 @@ int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev, bool *use_p2pdma); ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, bool use_p2pdma); +bool pci_test_p2p(struct device *devA, struct device *devB); #else /* CONFIG_PCI_P2PDMA */ static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset) @@ -97,6 +98,11 @@ static inline ssize_t pci_p2pdma_enable_show(char *page, { return sprintf(page, "none\n"); }
+static inline bool pci_test_p2p(struct device *devA, struct device *devB) +{
return false;
+} #endif /* CONFIG_PCI_P2PDMA */
-- 2.17.2
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