于 2013/4/22 14:36, Benjamin Herrenschmidt 写道:
On Mon, 2013-04-22 at 02:13 -0400, Mike Qiu wrote:
In pnv_pci_read_config() or pnv_pci_write_config(), we never check if
the PCI controller is valid before converting that into platform
dependent one, this is very dangerous.
To avoid this potential risks, the patch check PCI controller first
before use it.
I don't think there's any remote possibility of that happening, is
there ?
Yes, I agree, I don't exactly mean that it maybe happen, but the code
try to check the pci_controller pointer and the way it try is useless,
because if this happens, the system will crash before check: try to access
the "NULL" pointer.
My patch just makes the code more stable and robust.
Anyway, I think it's better to remove the check code as it is useless, as it
will shows that this "NULL" pci_controller pointer may happen...
Thanks
Mike
If it does, maybe it warrants a WARN_ON...
Ben.
Signed-off-by: Mike Qiu <qiudayu@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/platforms/powernv/pci.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index b8b8e0b..e7b7f1a 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -286,11 +286,11 @@ static int pnv_pci_read_config(struct pci_bus *bus,
int where, int size, u32 *val)
{
struct pci_controller *hose = pci_bus_to_host(bus);
- struct pnv_phb *phb = hose->private_data;
+ struct pnv_phb *phb = hose ? hose->private_data : NULL;
u32 bdfn = (((uint64_t)bus->number) << 8) | devfn;
s64 rc;
- if (hose == NULL)
+ if (!phb)
return PCIBIOS_DEVICE_NOT_FOUND;
switch (size) {
@@ -330,10 +330,10 @@ static int pnv_pci_write_config(struct pci_bus *bus,
int where, int size, u32 val)
{
struct pci_controller *hose = pci_bus_to_host(bus);
- struct pnv_phb *phb = hose->private_data;
+ struct pnv_phb *phb = hose ? hose->private_data : NULL;
u32 bdfn = (((uint64_t)bus->number) << 8) | devfn;
- if (hose == NULL)
+ if (!phb)
return PCIBIOS_DEVICE_NOT_FOUND;
cfg_dbg("pnv_pci_write_config bus: %x devfn: %x +%x/%x -> %08x\n",
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