Re: Write to srvio_numvfs triggers kernel panic

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Mon, May 09, 2022 at 10:58:57AM -0600, Alex Williamson wrote:
> is_physfn = 0, is_virtfn = 0: A non-SR-IOV function
> is_physfn = 1, is_virtfn = 0: An SR-IOV PF
> is_physfn = 0, is_virtfn = 1: An SR-IOV VF
> 
> As implemented with bit fields this is 2 bits, which is more space
> efficient than an enum.  Thanks,

A two-bit bitfield with explicit constants for the values would probably
still much eaiser to understand.

And there is some code that seems to intepret is_physfn a bit odd, e.g.:

arch/powerpc/kernel/eeh_sysfs.c:        np = pci_device_to_OF_node(pdev->is_physfn ? pdev : pdev->physfn);
arch/powerpc/kernel/eeh_sysfs.c:        np = pci_device_to_OF_node(pdev->is_physfn ? pdev : pdev->physfn);