On Wed, 2015-01-21 at 20:48 -0600, Kim Phillips wrote:

On Tue, 20 Jan 2015 18:31:32 -0600
Scott Wood [off-list ref] wrote:

quoted

On Tue, 2015-01-20 at 14:03 -0600, Kim Phillips wrote:

quoted

Fix this:

  CC      arch/powerpc/sysdev/fsl_pci.o
arch/powerpc/sysdev/fsl_pci.c: In function 'fsl_pcie_check_link':
arch/powerpc/sysdev/fsl_pci.c:91:1: error: the frame size of 1360 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

when configuring FRAME_WARN, by converting the allocation from the
stack to the heap.  We use GFP_ATOMIC since this function can be
called with interrupts disabled.

Signed-off-by: Kim Phillips <redacted>
---
 arch/powerpc/sysdev/fsl_pci.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 6455c1e..635d743 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c

@@ -69,11 +69,13 @@ static int fsl_pcie_check_link(struct pci_controller *hose)
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
 		if (hose->ops->read == fsl_indirect_read_config) {
-			struct pci_bus bus;
-			bus.number = hose->first_busno;
-			bus.sysdata = hose;
-			bus.ops = hose->ops;
-			indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
+			struct pci_bus *bus;
+			bus = kmalloc(sizeof(*bus), GFP_ATOMIC);
+			bus->number = hose->first_busno;

Missing check for allocation failure.

thanks.

quoted

Do we not have a real struct pci_bus we can use here?  Or refactor
indirect_read_config() to take hose and bus number instead?

indirect_read_config() can't be refactored because it is also used
in the generic struct pci_ops.  Unless you mean making an
__indirect_read_config that the original would call, 

Yes, that's what I mean.

but that doesn't look that trivial given it calls pci_exclude_device with a
struct pci_controller hose.

Check for excluded devices in indirect_read_config(), not
__indirect_read_config().

quoted

If putting a pci_bus struct on the stack is no longer OK, then
fake_pci_bus() should be fixed as well.  I wonder if GCC is allocating
separate pci_bus structs on the stack for this one and the one that
early_read_config_dword() uses...

fake_pci_bus()' version is static, so it's not on the stack.

given that, maybe fsl_pcie_check_link()'s should be static too?

Oh.  How would you ensure that it's only called once at a time?  It
doesn't look like this is only called during early boot.
fsl_pcie_check_link() is called every time we do any config read through
the normal interface.  This is also a concern for the call to
early_read_config_dword().

-Scott