Re: [PATCH v8 16/20] PCI/AER: Convert aer_get_device_error_info(), aer_print_error() to index

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Thu, 22 May 2025, Bjorn Helgaas wrote:

> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> Previously aer_get_device_error_info() and aer_print_error() took a pointer
> to struct aer_err_info and a pointer to a pci_dev.  Typically the pci_dev
> was one of the elements of the aer_err_info.dev[] array (DPC was an
> exception, where the dev[] array was unused).
> 
> Convert aer_get_device_error_info() and aer_print_error() to take an index
> into the aer_err_info.dev[] array instead.  A future patch will add
> per-device ratelimit information, so the index makes it convenient to find
> the ratelimit associated with the device.
> 
> To accommodate DPC, set info->dev[0] to the DPC port before using these
> interfaces.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
>  drivers/pci/pci.h      |  4 ++--
>  drivers/pci/pcie/aer.c | 33 +++++++++++++++++++++++----------
>  drivers/pci/pcie/dpc.c |  8 ++++++--
>  3 files changed, 31 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 1a9bfc708757..e1a28215967f 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -605,8 +605,8 @@ struct aer_err_info {
>  	struct pcie_tlp_log tlp;	/* TLP Header */
>  };
>  
> -int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info);
> -void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
> +int aer_get_device_error_info(struct aer_err_info *info, int i);
> +void aer_print_error(struct aer_err_info *info, int i);
>  
>  int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
>  		      unsigned int tlp_len, bool flit,
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 787a953fb331..237741e66d28 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -705,12 +705,18 @@ static void aer_print_source(struct pci_dev *dev, struct aer_err_info *info,
>  		 found ? "" : " (no details found");
>  }
>  
> -void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
> +void aer_print_error(struct aer_err_info *info, int i)
>  {
> -	int layer, agent;
> -	int id = pci_dev_id(dev);
> +	struct pci_dev *dev;
> +	int layer, agent, id;
>  	const char *level = info->level;
>  
> +	if (i >= AER_MAX_MULTI_ERR_DEVICES)
> +		return;

Are these OoB checks actually indication of a logic error in the caller 
side which would perhaps warrant using
	if (WARN_ON_ONCE(i >= AER_MAX_MULTI_ERR_DEVICES))
?

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

> +
> +	dev = info->dev[i];
> +	id = pci_dev_id(dev);
> +
>  	pci_dev_aer_stats_incr(dev, info);
>  	trace_aer_event(pci_name(dev), (info->status & ~info->mask),
>  			info->severity, info->tlp_header_valid, &info->tlp);
> @@ -1193,19 +1199,26 @@ EXPORT_SYMBOL_GPL(aer_recover_queue);
>  
>  /**
>   * aer_get_device_error_info - read error status from dev and store it to info
> - * @dev: pointer to the device expected to have an error record
>   * @info: pointer to structure to store the error record
> + * @i: index into info->dev[]
>   *
>   * Return: 1 on success, 0 on error.
>   *
>   * Note that @info is reused among all error devices. Clear fields properly.
>   */
> -int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
> +int aer_get_device_error_info(struct aer_err_info *info, int i)
>  {
> -	int type = pci_pcie_type(dev);
> -	int aer = dev->aer_cap;
> +	struct pci_dev *dev;
> +	int type, aer;
>  	u32 aercc;
>  
> +	if (i >= AER_MAX_MULTI_ERR_DEVICES)
> +		return 0;
> +
> +	dev = info->dev[i];
> +	aer = dev->aer_cap;
> +	type = pci_pcie_type(dev);
> +
>  	/* Must reset in this function */
>  	info->status = 0;
>  	info->tlp_header_valid = 0;
> @@ -1257,11 +1270,11 @@ static inline void aer_process_err_devices(struct aer_err_info *e_info)
>  
>  	/* Report all before handling them, to not lose records by reset etc. */
>  	for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
> -		if (aer_get_device_error_info(e_info->dev[i], e_info))
> -			aer_print_error(e_info->dev[i], e_info);
> +		if (aer_get_device_error_info(e_info, i))
> +			aer_print_error(e_info, i);
>  	}
>  	for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
> -		if (aer_get_device_error_info(e_info->dev[i], e_info))
> +		if (aer_get_device_error_info(e_info, i))
>  			handle_error_source(e_info->dev[i], e_info);
>  	}
>  }
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index 7ae1590ea1da..fc18349614d7 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -253,6 +253,10 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
>  		info->severity = AER_NONFATAL;
>  
>  	info->level = KERN_ERR;
> +
> +	info->dev[0] = dev;
> +	info->error_dev_num = 1;
> +
>  	return 1;
>  }
>  
> @@ -270,8 +274,8 @@ void dpc_process_error(struct pci_dev *pdev)
>  		pci_warn(pdev, "containment event, status:%#06x: unmasked uncorrectable error detected\n",
>  			 status);
>  		if (dpc_get_aer_uncorrect_severity(pdev, &info) &&
> -		    aer_get_device_error_info(pdev, &info)) {
> -			aer_print_error(pdev, &info);
> +		    aer_get_device_error_info(&info, 0)) {
> +			aer_print_error(&info, 0);
>  			pci_aer_clear_nonfatal_status(pdev);
>  			pci_aer_clear_fatal_status(pdev);
>  		}
> 

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