Re: [PATCH] PCI: Tone down resource mmap warning

[Fengguang Wu]

This is perhaps the most clean solution. Thank you for the patch!  -fengguang

On Wed, Nov 29, 2017 at 04:57:08PM -0600, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> When a process tries to mmap more space than is available in a PCI BAR, we
> emit a warning and a backtrace.  The mmap fails anyway, so the backtrace is
> mainly for debugging.  It seems like overkill now, so reduce this to a
> dev_info() and remove the backtrace.
>
> This was added by b5ff7df3df9e ("Check mapped ranges on sysfs resource
> files").
>
> Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> drivers/pci/pci-sysfs.c |    6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 06c7f0b85cd2..97f071674605 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -1217,11 +1217,9 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,
> 		return -EINVAL;
>
> 	if (!pci_mmap_fits(pdev, bar, vma, PCI_MMAP_SYSFS)) {
> -		WARN(1, "process \"%s\" tried to map 0x%08lx bytes at page 0x%08lx on %s BAR %d (start 0x%16Lx, size 0x%16Lx)\n",
> +		dev_info(&pdev->dev, "process \"%s\" tried to map 0x%lx bytes at page 0x%lx of BAR %d %pR\n",
> 			current->comm, vma->vm_end-vma->vm_start, vma->vm_pgoff,
> -			pci_name(pdev), bar,
> -			(u64)pci_resource_start(pdev, bar),
> -			(u64)pci_resource_len(pdev, bar));
> +			bar, res);
> 		return -EINVAL;
> 	}
> 	mmap_type = res->flags & IORESOURCE_MEM ? pci_mmap_mem : pci_mmap_io;