On Thursday 04 February 2021 15:50:19 Bjorn Helgaas wrote: > [+cc Oliver, Pali, Krzysztof]
Just to note that extending or using sysfs_initialized introduces another race condition into kernel code which results in PCI fatal errors. Details are in email discussion which Bjorn already sent. > s/also/Also/ in subject > > On Thu, Feb 04, 2021 at 05:58:30PM +0100, Daniel Vetter wrote: > > We are already doing this for all the regular sysfs files on PCI > > devices, but not yet on the legacy io files on the PCI buses. Thus far > > now problem, but in the next patch I want to wire up iomem revoke > > support. That needs the vfs up an running already to make so that > > iomem_get_mapping() works. > > s/now problem/no problem/ > s/an running/and running/ > s/so that/sure that/ ? > > iomem_get_mapping() doesn't exist; I don't know what that should be. > > > Wire it up exactly like the existing code. Note that > > pci_remove_legacy_files() doesn't need a check since the one for > > pci_bus->legacy_io is sufficient. > > I'm not sure exactly what you mean by "the existing code." I could > probably figure it out, but it would save time to mention the existing > function here. > > This looks like another instance where we should really apply Oliver's > idea of converting these to attribute_groups [1]. > > The cover letter mentions options discussed with Greg in [2], but I > don't think the "sysfs_initialized" hack vs attribute_groups was part > of that discussion. > > It's not absolutely a show-stopper, but it *is* a shame to extend the > sysfs_initialized hack if attribute_groups could do this more cleanly > and help solve more than one issue. > > Bjorn > > [1] > https://lore.kernel.org/r/caosf1chss03dbsdo4pmttmp0tceu5kscn704zewlkgxqzbf...@mail.gmail.com > [2] > https://lore.kernel.org/dri-devel/cakmk7ugrddrbtj0oyzqqc0cgrqwc2f3tfju9vlfm2jjufaz...@mail.gmail.com/ > > > Signed-off-by: Daniel Vetter <daniel.vet...@intel.com> > > Cc: Stephen Rothwell <s...@canb.auug.org.au> > > Cc: Jason Gunthorpe <j...@ziepe.ca> > > Cc: Kees Cook <keesc...@chromium.org> > > Cc: Dan Williams <dan.j.willi...@intel.com> > > Cc: Andrew Morton <a...@linux-foundation.org> > > Cc: John Hubbard <jhubb...@nvidia.com> > > Cc: Jérôme Glisse <jgli...@redhat.com> > > Cc: Jan Kara <j...@suse.cz> > > Cc: Dan Williams <dan.j.willi...@intel.com> > > Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> > > Cc: linux...@kvack.org > > Cc: linux-arm-ker...@lists.infradead.org > > Cc: linux-samsung-...@vger.kernel.org > > Cc: linux-me...@vger.kernel.org > > Cc: Bjorn Helgaas <bhelg...@google.com> > > Cc: linux-...@vger.kernel.org > > --- > > drivers/pci/pci-sysfs.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > index fb072f4b3176..0c45b4f7b214 100644 > > --- a/drivers/pci/pci-sysfs.c > > +++ b/drivers/pci/pci-sysfs.c > > @@ -927,6 +927,9 @@ void pci_create_legacy_files(struct pci_bus *b) > > { > > int error; > > > > + if (!sysfs_initialized) > > + return; > > + > > b->legacy_io = kcalloc(2, sizeof(struct bin_attribute), > > GFP_ATOMIC); > > if (!b->legacy_io) > > @@ -1448,6 +1451,7 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev) > > static int __init pci_sysfs_init(void) > > { > > struct pci_dev *pdev = NULL; > > + struct pci_bus *pbus = NULL; > > int retval; > > > > sysfs_initialized = 1; > > @@ -1459,6 +1463,9 @@ static int __init pci_sysfs_init(void) > > } > > } > > > > + while ((pbus = pci_find_next_bus(pbus))) > > + pci_create_legacy_files(pbus); > > + > > return 0; > > } > > late_initcall(pci_sysfs_init); > > -- > > 2.30.0 > > > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-ker...@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
