Re: [PATCH] pci/shpchp: no claim on pcie port device

On Tue, Jun 12, 2018 at 2:57 PM Christoph Hellwig [off-list ref] wrote:

On Tue, Jun 12, 2018 at 02:42:13PM +0800, Pingfan Liu wrote:

quoted

The Linux Device Driver Model allows a physical device to be handled
by only a single driver. But at present, both shpchp and portdrv_pci
claim PCI_CLASS_BRIDGE_PCI, and touch devices_kset. This causes a
few problems, one is the wrong shutdown seq of devices, owing to the
broken devices_kset.

How can they both touch devices_kset?  Once one driver has claimed the
device it should not be available to others.

Unfortunately, it could be.  There are two code path for do_one_initcall
kernel_init->..->do_one_initcall->pcie_portdrv_init
And
load_module->do_init_module->do_one_initcall->shpcd_init

quoted

+     /* do not claim pcie port device */
+     if (pci_is_pcie(dev) &&
+         ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) ||
+          (pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM) ||
+          (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM)))
+             return -ENODEV;

No need for the inner braces.

OK.

Thanks,
Pingfan