linux-kernel - Re: [PATCH v3 2/3] aerdrv: Enhanced AER logging

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Date:	Sat, 1 Dec 2012 17:01:44 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Lance Ortiz <lance.ortiz@...com>
Cc:	bhelgaas@...gle.com, lance_ortiz@...mail.com, jiang.liu@...wei.com,
	tony.luck@...el.com, rostedt@...dmis.org, mchehab@...hat.com,
	linux-acpi@...r.kernel.org, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/3] aerdrv: Enhanced AER logging

On Sat, Dec 01, 2012 at 04:51:30PM +0100, Borislav Petkov wrote:
> > @@ -281,9 +286,17 @@ static void cper_print_pcie(const char *pfx, const struct cper_sec_pcie *pcie,
> >  	"%s""bridge: secondary_status: 0x%04x, control: 0x%04x\n",
> >  	pfx, pcie->bridge.secondary_status, pcie->bridge.control);
> >  #ifdef CONFIG_ACPI_APEI_PCIEAER
> > -	if (pcie->validation_bits & CPER_PCIE_VALID_AER_INFO) {
> > +	dev = pci_get_domain_bus_and_slot(pcie->device_id.segment,
> > +			pcie->device_id.bus, pcie->device_id.function);
> > +	if (!dev)
> > +		pr_info("PCI AER Cannot get PCI device %04x:%02x:%02x.%d\n",
> > +			pcie->device_id.segment, pcie->device_id.bus,
> > +			pcie->device_id.slot, pcie->device_id.function);
> > +
> > +	if (pcie->validation_bits & CPER_PCIE_VALID_AER_INFO && dev) {
> 
> You don't need to test dev here because you've tested for !dev in the
> line above...
> 
> >  		struct aer_capability_regs *aer_regs = (void *)pcie->aer_info;
> > -		cper_print_aer(pfx, gdata->error_severity, aer_regs);
> > +		cper_print_aer(dev, gdata->error_severity, aer_regs);
> > +		pci_dev_put(dev);
> 
> ... and thus this pci_dev_put() has to be unconditional, i.e. after the
> if test.

Not entirely correct: you don't need to test dev if you return early in
the !dev case. And AFAICT you should return early because if you can't
get dev, you can't call cper_print_aer() afterwards.

IOW, this hunk should look like this:

@@ -281,10 +286,19 @@ static void cper_print_pcie(const char *pfx, const struct cper_sec_pcie *pcie,
        "%s""bridge: secondary_status: 0x%04x, control: 0x%04x\n",
        pfx, pcie->bridge.secondary_status, pcie->bridge.control);
 #ifdef CONFIG_ACPI_APEI_PCIEAER
-       if (pcie->validation_bits & CPER_PCIE_VALID_AER_INFO) {
-               struct aer_capability_regs *aer_regs = (void *)pcie->aer_info;
-               cper_print_aer(pfx, gdata->error_severity, aer_regs);
+       dev = pci_get_domain_bus_and_slot(pcie->device_id.segment,
+                       pcie->device_id.bus, pcie->device_id.function);
+       if (!dev) {
+               pr_info("PCI AER Cannot get PCI device %04x:%02x:%02x.%d\n",
+                       pcie->device_id.segment, pcie->device_id.bus,
+                       pcie->device_id.slot, pcie->device_id.function);
+               return;
        }
+
+       if (pcie->validation_bits & CPER_PCIE_VALID_AER_INFO)
+               cper_print_aer(dev, gdata->error_severity,
+                              (struct aer_capability_regs *)pcie->aer_info);
+       pci_dev_put(dev);
 #endif
 }

Thanks.

-- 
Regards/Gruss,
    Boris.
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