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charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" In order to use upstream_bridge_distance_warn() from a dma_map function, it must not sleep. However, pci_get_slot() takes the pci_bus_sem so it might sleep. In order to avoid this, try to get the host bridge's device from bus->self, and if that is not set just get the first element in the list. It should be impossible for the host bridges device to go away while references are held on child devices, so the first element should not change and this should be safe. Signed-off-by: Logan Gunthorpe --- 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 bd89437faf06..2135fe69bb07 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -311,11 +311,15 @@ static const struct pci_p2pdma_whitelist_entry { static bool __host_bridge_whitelist(struct pci_host_bridge *host, bool same_host_bridge) { - struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0)); const struct pci_p2pdma_whitelist_entry *entry; + struct pci_dev *root = host->bus->self; unsigned short vendor, device; if (!root) + root = list_first_entry_or_null(&host->bus->devices, + struct pci_dev, bus_list); + + if (!root || root->devfn) return false; vendor = root->vendor; -- 2.20.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu