Re: [PATCH] PCI/MSI: Export all remapped MSIs to sysfs attributes

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Sep 24, 2015 at 01:31:16AM +0200, Romain Bezut wrote:
> irqbalance uses these attributes to populate its internal database, which is
> then used to bind the irq on the appropriate NUMA node.
> 
> On a device accepting multiple MSIs and with interrupt remapping enabled,
> only the first irq entry is exported to msi_irqs directory.
> This results in irqbalance having no clue of the NUMA affinity for the extra
> irqs and starting to bind them on random nodes.
> 
> This patch exports all MSI interrupts as sysfs attributes when relevant.
> 
> Signed-off-by: Romain Bezut <rbezut@gmail.com>

Applied with Thomas' ack to pci/msi for v4.4, thanks, Romain!
> ---
>  drivers/pci/msi.c | 31 +++++++++++++++++--------------
>  1 file changed, 17 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index d449714..324a164 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -475,10 +475,11 @@ static int populate_msi_sysfs(struct pci_dev *pdev)
>  	int ret = -ENOMEM;
>  	int num_msi = 0;
>  	int count = 0;
> +	int i;
>  
>  	/* Determine how many msi entries we have */
>  	for_each_pci_msi_entry(entry, pdev)
> -		++num_msi;
> +		num_msi += entry->nvec_used;
>  	if (!num_msi)
>  		return 0;
>  
> @@ -487,19 +488,21 @@ static int populate_msi_sysfs(struct pci_dev *pdev)
>  	if (!msi_attrs)
>  		return -ENOMEM;
>  	for_each_pci_msi_entry(entry, pdev) {
> -		msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
> -		if (!msi_dev_attr)
> -			goto error_attrs;
> -		msi_attrs[count] = &msi_dev_attr->attr;
> -
> -		sysfs_attr_init(&msi_dev_attr->attr);
> -		msi_dev_attr->attr.name = kasprintf(GFP_KERNEL, "%d",
> -						    entry->irq);
> -		if (!msi_dev_attr->attr.name)
> -			goto error_attrs;
> -		msi_dev_attr->attr.mode = S_IRUGO;
> -		msi_dev_attr->show = msi_mode_show;
> -		++count;
> +		for (i = 0; i < entry->nvec_used; i++) {
> +			msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
> +			if (!msi_dev_attr)
> +				goto error_attrs;
> +			msi_attrs[count] = &msi_dev_attr->attr;
> +
> +			sysfs_attr_init(&msi_dev_attr->attr);
> +			msi_dev_attr->attr.name = kasprintf(GFP_KERNEL, "%d",
> +							    entry->irq + i);
> +			if (!msi_dev_attr->attr.name)
> +				goto error_attrs;
> +			msi_dev_attr->attr.mode = S_IRUGO;
> +			msi_dev_attr->show = msi_mode_show;
> +			++count;
> +		}
>  	}
>  
>  	msi_irq_group = kzalloc(sizeof(*msi_irq_group), GFP_KERNEL);
> -- 
> 2.4.9
> 
> --
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