Re: [PATCH v3] aerdrv: Move cper_print_aer() call out of interrupt context

[Rafael J. Wysocki]

On Wednesday, May 29, 2013 01:03:26 PM Lance Ortiz wrote:
> The following warning was seen on 3.9 when a corrected PCIe error was being
> handled by the AER subsystem.
> 
> WARNING: at .../drivers/pci/search.c:214 pci_get_dev_by_id+0x8a/0x90()
> 
> This occurred because a call to pci_get_domain_bus_and_slot() was added to
> cper_print_pcie() to setup for the call to cper_print_aer().  The warning
> showed up because cper_print_pcie() is called in an interrupt context and
> pci_get* functions are not supposed to be called in that context.
> 
> The solution is to move the cper_print_aer() call out of the interrupt
> context and into aer_recover_work_func() to avoid any warnings when calling
> pci_get* functions.
> 
> v2 - Re-worded header text.  Removed prefix arg from cper_print_aer().
>      Added TODO message in cper_print_aer().
> v3 - Changed type of u8* to struct aer_capability_regs* in the code
>      to avoid too much casting based on comment from Bjorn Helgaas.
> 
> Signed-off-by: Lance Ortiz <lance.ortiz@xxxxxx>
> Acked-by: Borislav Petkov <bp@xxxxxxx>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

> ---
> 
>  drivers/acpi/apei/cper.c               |   18 ------------------
>  drivers/acpi/apei/ghes.c               |    4 +++-
>  drivers/pci/pcie/aer/aerdrv_core.c     |    5 ++++-
>  drivers/pci/pcie/aer/aerdrv_errprint.c |   10 ++++++++--
>  include/linux/aer.h                    |    5 +++--
>  5 files changed, 18 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/acpi/apei/cper.c b/drivers/acpi/apei/cper.c
> index 1e5d8a4..8713229 100644
> --- a/drivers/acpi/apei/cper.c
> +++ b/drivers/acpi/apei/cper.c
> @@ -250,10 +250,6 @@ static const char *cper_pcie_port_type_strs[] = {
>  static void cper_print_pcie(const char *pfx, const struct cper_sec_pcie *pcie,
>  			    const struct acpi_hest_generic_data *gdata)
>  {
> -#ifdef CONFIG_ACPI_APEI_PCIEAER
> -	struct pci_dev *dev;
> -#endif
> -
>  	if (pcie->validation_bits & CPER_PCIE_VALID_PORT_TYPE)
>  		printk("%s""port_type: %d, %s\n", pfx, pcie->port_type,
>  		       pcie->port_type < ARRAY_SIZE(cper_pcie_port_type_strs) ?
> @@ -285,20 +281,6 @@ static void cper_print_pcie(const char *pfx, const struct cper_sec_pcie *pcie,
>  		printk(
>  	"%s""bridge: secondary_status: 0x%04x, control: 0x%04x\n",
>  	pfx, pcie->bridge.secondary_status, pcie->bridge.control);
> -#ifdef CONFIG_ACPI_APEI_PCIEAER
> -	dev = pci_get_domain_bus_and_slot(pcie->device_id.segment,
> -			pcie->device_id.bus, pcie->device_id.function);
> -	if (!dev) {
> -		pr_err("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(pfx, dev, gdata->error_severity,
> -				(struct aer_capability_regs *) pcie->aer_info);
> -	pci_dev_put(dev);
> -#endif
>  }
>  
>  static const char *apei_estatus_section_flag_strs[] = {
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index d668a8a..403baf4 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -454,7 +454,9 @@ static void ghes_do_proc(struct ghes *ghes,
>  				aer_severity = cper_severity_to_aer(sev);
>  				aer_recover_queue(pcie_err->device_id.segment,
>  						  pcie_err->device_id.bus,
> -						  devfn, aer_severity);
> +						  devfn, aer_severity,
> +						  (struct aer_capability_regs *)
> +						  pcie_err->aer_info);
>  			}
>  
>  		}
> diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
> index 564d97f..120549a 100644
> --- a/drivers/pci/pcie/aer/aerdrv_core.c
> +++ b/drivers/pci/pcie/aer/aerdrv_core.c
> @@ -582,6 +582,7 @@ struct aer_recover_entry
>  	u8	devfn;
>  	u16	domain;
>  	int	severity;
> +	struct aer_capability_regs *regs;
>  };
>  
>  static DEFINE_KFIFO(aer_recover_ring, struct aer_recover_entry,
> @@ -595,7 +596,7 @@ static DEFINE_SPINLOCK(aer_recover_ring_lock);
>  static DECLARE_WORK(aer_recover_work, aer_recover_work_func);
>  
>  void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
> -		       int severity)
> +		       int severity, struct aer_capability_regs *aer_regs)
>  {
>  	unsigned long flags;
>  	struct aer_recover_entry entry = {
> @@ -603,6 +604,7 @@ void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
>  		.devfn		= devfn,
>  		.domain		= domain,
>  		.severity	= severity,
> +		.regs		= aer_regs,
>  	};
>  
>  	spin_lock_irqsave(&aer_recover_ring_lock, flags);
> @@ -629,6 +631,7 @@ static void aer_recover_work_func(struct work_struct *work)
>  			       PCI_SLOT(entry.devfn), PCI_FUNC(entry.devfn));
>  			continue;
>  		}
> +		cper_print_aer(pdev, entry.severity, entry.regs);
>  		do_recovery(pdev, entry.severity);
>  		pci_dev_put(pdev);
>  	}
> diff --git a/drivers/pci/pcie/aer/aerdrv_errprint.c b/drivers/pci/pcie/aer/aerdrv_errprint.c
> index 5ab1425..f277dc3 100644
> --- a/drivers/pci/pcie/aer/aerdrv_errprint.c
> +++ b/drivers/pci/pcie/aer/aerdrv_errprint.c
> @@ -220,13 +220,19 @@ int cper_severity_to_aer(int cper_severity)
>  }
>  EXPORT_SYMBOL_GPL(cper_severity_to_aer);
>  
> -void cper_print_aer(const char *prefix, struct pci_dev *dev, int cper_severity,
> +void cper_print_aer(struct pci_dev *dev, int cper_severity,
>  		    struct aer_capability_regs *aer)
>  {
>  	int aer_severity, layer, agent, status_strs_size, tlp_header_valid = 0;
>  	u32 status, mask;
>  	const char **status_strs;
>  
> +	/*
> +	 * TODO: This function needs to be re-written so that it's output
> +	 * matches the output of aer_print_error().  Right now, the output
> +	 * is formatted very differently.
> +	 */
> +
>  	aer_severity = cper_severity_to_aer(cper_severity);
>  	if (aer_severity == AER_CORRECTABLE) {
>  		status = aer->cor_status;
> @@ -244,7 +250,7 @@ void cper_print_aer(const char *prefix, struct pci_dev *dev, int cper_severity,
>  	agent = AER_GET_AGENT(aer_severity, status);
>  	dev_err(&dev->dev, "aer_status: 0x%08x, aer_mask: 0x%08x\n",
>  	       status, mask);
> -	cper_print_bits(prefix, status, status_strs, status_strs_size);
> +	cper_print_bits("", status, status_strs, status_strs_size);
>  	dev_err(&dev->dev, "aer_layer=%s, aer_agent=%s\n",
>  	       aer_error_layer[layer], aer_agent_string[agent]);
>  	if (aer_severity != AER_CORRECTABLE)
> diff --git a/include/linux/aer.h b/include/linux/aer.h
> index ec10e1b..737f90a 100644
> --- a/include/linux/aer.h
> +++ b/include/linux/aer.h
> @@ -49,10 +49,11 @@ static inline int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev)
>  }
>  #endif
>  
> -extern void cper_print_aer(const char *prefix, struct pci_dev *dev,
> +extern void cper_print_aer(struct pci_dev *dev,
>  			   int cper_severity, struct aer_capability_regs *aer);
>  extern int cper_severity_to_aer(int cper_severity);
>  extern void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
> -			      int severity);
> +			      int severity,
> +			      struct aer_capability_regs *aer_regs);
>  #endif //_AER_H_
>  
> 
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-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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