On Mon, Sep 27, 2021 at 12:33:21PM +0200, Sergio M. Iglesias wrote:
> Hello!
>
> I have checked the "__refdata" tag that appears in the file
> "drivers/pci/controller/dwc/pci-keystone.c" and it is needed. The tag has
> been there since the creation of the file on commit 6e0832fa432e and
> nothing has changed since that would make it redundant.
>
> The reason it is needed is because the struct references "ks_pcie_probe",
> which is a function tagged as "__init", so the compiler will most likely
> complain about the "__refdata" being removed.
>
> Should I send a patch to add a comment explaining why it is a necessary
> tag as recommended in "include/linux/init.h"?
> > [...] so optimally document why the __ref is needed and why it's OK).
Thanks a lot for looking into this.
I'm not yet convinced that either the __init or the __refdata is
necessary. If there is a reason, it would not be "to silence a
compiler complaint"; it would be something like "the keystone platform
is different from all the other platforms because the other platforms
support X but keystone does not."
Also, there are a couple other .probe() functions that are marked
__init:
$ git grep "static int .*_pci.*_probe" drivers/pci | grep __init
drivers/pci/controller/dwc/pci-keystone.c:static int __init ks_pcie_probe(struct platform_device *pdev)
drivers/pci/controller/dwc/pci-layerscape-ep.c:static int __init ls_pcie_ep_probe(struct platform_device *pdev)
drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c:static int __init ls_pcie_g4_probe(struct platform_device *pdev)
drivers/pci/controller/pci-ixp4xx.c:static int __init ixp4xx_pci_probe(struct platform_device *pdev)
and their platform_driver structs are not marked __refdata:
$ git grep "static struct platform_driver" drivers/pci | grep __refdata
drivers/pci/controller/dwc/pci-keystone.c:static struct platform_driver ks_pcie_driver __refdata = {
I think this should all be more consistent: either all these __init
and __refdata annotations should be removed, or they should be used by
many more drivers.
Bjorn
