[PATCH] PCI: Also set up legacy files only after sysfs init

[Daniel Vetter]

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
no problem, but in the next patch I want to wire up iomem revoke
support. That needs the vfs up and running already to make sure that
iomem_get_mapping() works.

Wire it up exactly like the existing code in
pci_create_sysfs_dev_files(). Note that pci_remove_legacy_files()
doesn't need a check since the one for pci_bus->legacy_io is
sufficient.

An alternative solution would be to implement a callback in sysfs to
set up the address space from iomem_get_mapping() when userspace calls
mmap(). This also works, but Greg didn't really like that just to work
around an ordering issue when the kernel loads initially.

v2: Improve commit message (Bjorn)

Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
Cc: Stephen Rothwell <sfr at canb.auug.org.au>
Cc: Jason Gunthorpe <jgg at ziepe.ca>
Cc: Kees Cook <keescook at chromium.org>
Cc: Dan Williams <dan.j.williams at intel.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: John Hubbard <jhubbard at nvidia.com>
Cc: Jérôme Glisse <jglisse at redhat.com>
Cc: Jan Kara <jack at suse.cz>
Cc: Dan Williams <dan.j.williams at intel.com>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Cc: linux-mm at kvack.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-samsung-soc at vger.kernel.org
Cc: linux-media at vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: linux-pci at 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