Re: [PATCH v2] memremap: remove support for external pgmap refcounts

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Oct 28, 2021 at 05:10:17PM +0200, Christoph Hellwig wrote:
> No driver is left using the external pgmap refcount, so remove the
> code to support it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> index 50cdde3e9a8b2..316fd2f44df45 100644
> --- a/drivers/pci/p2pdma.c
> +++ b/drivers/pci/p2pdma.c
> @@ -219,7 +219,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
>  	error = gen_pool_add_owner(p2pdma->pool, (unsigned long)addr,
>  			pci_bus_address(pdev, bar) + offset,
>  			range_len(&pgmap->range), dev_to_node(&pdev->dev),
> -			pgmap->ref);
> +			&pgmap->ref);

I assume the change above is safe because of the one below.

>  struct dev_pagemap {
>  	struct vmem_altmap altmap;
> -	struct percpu_ref *ref;
> -	struct percpu_ref internal_ref;
> +	struct percpu_ref ref;