On Thursday, September 12, 2013 2:24 AM, Casey Leedom wrote:

   I agree that the redundant pci_set_drvdata(pdev, NULL) in
cxgb4vf_pci_probe() under the err_release_regions: label is unneeded,
but don't we need to NULL out the PCI Driver Data under the
err_free_adapter: label and also in cxgb4vf_pci_remove()?  Or is that
handled automatically in the PCI infrastructure code which calls the
Device Probe and Remove routines?  Mostly I was just being an
obsessively clean housewife assuming that we'd want to clean up these
references ...

No, 'pci_set_drvdata(pdev, NULL) under err_free_adapter label' is not
necessary.

As you know, pci_set_drvdata(pdev, NULL) calls dev_set_drvdata() as below:
pci_set_drvdata(pdev, NULL) is dev_set_drvdata(&pdev->dev, NULL).

./include/linux/pci.h
1504:static inline void pci_set_drvdata(struct pci_dev *pdev, void *data)
1505{
1506	dev_set_drvdata(&pdev->dev, data);
1507}


However, when the driver goes to err_free_adapter label,
The following sequence will be done.
    kfree(adapter) -> .... -> return -ENOMEM;

In this case,
when probe() returns error value such as '-ENOMEM',
really_probe() of driver core automatically calls 'dev_set_drvdata(dev, NULL)'
as below:

./drivers/base/dd.c
303-probe_failed:
304	devres_release_all(dev);
305	driver_sysfs_remove(dev);
306	dev->driver = NULL;
307	dev_set_drvdata(dev, NULL);

Thus, without 'pci_set_drvdata(pdev, NULL) under err_free_adapter label',
dev_set_drvdata(dev, NULL) can be called.

I already tested this with other drivers such as e1000e LAN card driver.

Best regards,
Jingoo Han