On Sat, Jul 27, 2013 at 1:39 AM, Bjorn Helgaas <bhelg...@google.com> wrote:
> [+cc Jiang, linux-pci, -cc bjorn.helg...@hp.com (dead address)]
>
> On Fri, Jul 26, 2013 at 05:10:39PM +0800, ethan zhao wrote:
>> Cleanup the -EINVAL return value handling and add warning message
>> for invalid
>> start,end,addr parameters.
>>
>> Signed-off-by: ethan.zhao <ethan.z...@oracle.com>
>
> This patch was corrupted, so I couldn't apply it directly. See
> Documentation/SubmittingPatches, sections 5-7.
>
>> ---
>> arch/x86/pci/mmconfig-shared.c | 12 ++++++------
>> 1 files changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
>> index 082e881..37f6c7f 100644
>> --- a/arch/x86/pci/mmconfig-shared.c
>> +++ b/arch/x86/pci/mmconfig-shared.c
>> @@ -700,8 +700,13 @@ int pci_mmconfig_insert(struct device *dev, u16
>> seg, u8 start, u8 end,
>> if (!(pci_probe & PCI_PROBE_MMCONF) || pci_mmcfg_arch_init_failed)
>> return -ENODEV;
>>
>> - if (start > end)
>> + if (start > end || !addr) {
>> + dev_warn(dev, FW_WARN
>> + "Invalid address to add MMCONFIG"
>> + "start %02x end %02x addr %pR\n",
>> + start, end, addr);
>> return -EINVAL;
>> + }
>
> I like the "!addr" cleanup.
>
> Did you actually see this problem on a machine?
>
> I expect this would be a BIOS bug, and one that should be found
> early in development, long before a machine is released.
> Therefore, I doubt that it's worth adding another printk for it.
> If an end-user sees this problem, I think we'll already get a
> generic message from check_segment().
>
Yes, Maybe I met a BIOS bug, but the mmconfig just yelled a failed message like
this, no other information
"fail to add MMCONFIG information, xx--xx can't access extended PCI
configuration space under this bridge"
While I look into the code, found there are detail messages for other
return values in pci_mmconfig_insert(),
But no for -EINVAL, that is not fair and force me to add more code to
debug the cause.
> I propose the patch below; what do you think?
>
>>
>> mutex_lock(&pci_mmcfg_lock);
>> cfg = pci_mmconfig_lookup(seg, start);
>> @@ -716,11 +721,6 @@ int pci_mmconfig_insert(struct device *dev, u16
>> seg, u8 start, u8 end,
>> return -EEXIST;
>> }
>>
>> - if (!addr) {
>> - mutex_unlock(&pci_mmcfg_lock);
>> - return -EINVAL;
>> - }
>> -
>> rc = -EBUSY;
>> cfg = pci_mmconfig_alloc(seg, start, end, addr);
>> if (cfg == NULL) {
>
>
>
> Author: ethan.zhao <ethan.z...@oracle.com>
> Date: Fri Jul 26 11:21:24 2013 -0600
>
> x86/PCI: MMCONFIG: Check earlier for MMCONFIG region at address zero
>
> We can check for addr being zero earlier and thus avoid the mutex_unlock()
> cleanup path.
>
> [bhelgaas: changelog, drop printk]
> Signed-off-by: ethan.zhao <ethan.z...@oracle.com>
> Signed-off-by: Bjorn Helgaas <bhelg...@google.com>
> Acked-by: Yinghai Lu <ying...@kerne.org>
>
> diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
> index 082e881..5596c7b 100644
> --- a/arch/x86/pci/mmconfig-shared.c
> +++ b/arch/x86/pci/mmconfig-shared.c
> @@ -700,7 +700,7 @@ int pci_mmconfig_insert(struct device *dev, u16 seg, u8
> start, u8 end,
> if (!(pci_probe & PCI_PROBE_MMCONF) || pci_mmcfg_arch_init_failed)
> return -ENODEV;
>
> - if (start > end)
> + if (start > end || !addr)
> return -EINVAL;
>
> mutex_lock(&pci_mmcfg_lock);
> @@ -716,11 +716,6 @@ int pci_mmconfig_insert(struct device *dev, u16 seg, u8
> start, u8 end,
> return -EEXIST;
> }
>
> - if (!addr) {
> - mutex_unlock(&pci_mmcfg_lock);
> - return -EINVAL;
> - }
> -
> rc = -EBUSY;
> cfg = pci_mmconfig_alloc(seg, start, end, addr);
> if (cfg == NULL) {
--
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