On Mon, Sep 27, 2021 at 10:31 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > 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. __init should definitely be removed. There's no guarantee that probe completes before init memory is freed even for built-in drivers. Rob