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Tue, 4 Aug 2026 02:26:09 +0000 Date: Mon, 3 Aug 2026 19:26:04 -0700 From: Alison Schofield To: Terry Bowman CC: Jonathan Cameron , Dave Jiang , Vishal Verma , Davidlohr Bueso , Bjorn Helgaas , "Rafael J . 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Computing the DSN there via pci_get_dsn() requires PCI > configuration space reads, which are slow, can fail when the link is > down or frozen, and may not be safe in some contexts. > > Add a u64 dsn field to struct pci_dev and populate it from pci_get_dsn() > during pci_init_capabilities() at probe time via pci_dsn_init(). Only > write dev->dsn when the read succeeds. The zero initial value from > pci_dev allocation already represents 'no DSN available.' > > Remove the now-redundant dsn member from the pciehp struct controller > along with its kernel-doc. Drop the pci_get_slot()/pci_dev_put() pairs > in pciehp_configure_device() and pcie_init() that existed solely to > read the DSN into ctrl->dsn. Use pdev->dsn in pciehp_device_replaced() > for the device-replacement comparison. > > pci_get_dsn() is not modified because it remains a pure config-space read > with no side effects on pci_dev. The cache is written exclusively by > pci_dsn_init() at probe time. > Reviewed-by: Alison Schofield