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SubjectRe: [PATCH] pci: Make pci_dev struct point to NULL.
* Rakib Mullick <rakib.mullick@gmail.com>:
>
> Since *pdev might be uninitialized. But if we are sure that it
> is not uninitialized then it is okay.
>
> And yes - althrough we weren't warned by the compiler.

Let's start over.

This is the function:

965 static int __ref enable_device(struct acpiphp_slot *slot)
966 {
967 struct pci_dev *dev;

Your patch makes this change:
struct pci_dev *dev = NULL;

968 struct pci_bus *bus = slot->bridge->pci_bus;
969 struct list_head *l;
970 struct acpiphp_func *func;
971 int retval = 0;
972 int num, max, pass;
973 acpi_status status;
974
975 if (slot->flags & SLOT_ENABLED)
976 goto err_exit;

Here, if the slot is already enabled, we goto the err_exit label
(below). We haven't touched 'dev' yet.

Otherwise, we call pci_get_slot().

977
978 /* sanity check: dev should be NULL when hot-plugged in */
979 dev = pci_get_slot(bus, PCI_DEVFN(slot->device, 0));
980 if (dev) {
981 /* This case shouldn't happen */
982 err("pci_dev structure already exists.\n");
983 pci_dev_put(dev);
984 retval = -1;
985 goto err_exit;
986 }

If pci_get_slot() finds the devfn, it returns the pointer to the
pdev, puts it into 'dev' and we return early.

If it cannot find the devfn, then we put NULL into dev and
continue with the rest of the function.

1044 err_exit:
1045 return retval;
1046 }


At no point that I can tell do we ever access an uninitialized
'dev'.

Please explain to me one more time what you think you are fixing.

Thanks,
/ac


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