linux-kernel - Re: [PATCH v3 8/8] mm: Fix exports that inadvertently make put_page() EXPORT_SYMBOL

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Date:   Mon, 18 Jun 2018 23:59:07 -0700
From:   John Hubbard <jhubbard@...dia.com>
To:     Dan Williams <dan.j.williams@...el.com>,
        <akpm@...ux-foundation.org>
CC:     Joe Gorse <jhgorse@...il.com>, <hch@....de>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 8/8] mm: Fix exports that inadvertently make put_page()
 EXPORT_SYMBOL_GPL

On 06/18/2018 11:05 PM, Dan Williams wrote:
> Now that all producers of dev_pagemap instances in the kernel are
> properly converted to EXPORT_SYMBOL_GPL, fix up implicit consumers that
> interact with dev_pagemap owners via put_page(). To reiterate,
> dev_pagemap producers are EXPORT_SYMBOL_GPL because they adopt and
> modify core memory management interfaces such that the dev_pagemap owner
> can interact with all other kernel infrastructure and sub-systems
> (drivers, filesystems, etc...) that consume page structures.
> 
> Fixes: e76384884344 ("mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS")
> Reported-by: Joe Gorse <jhgorse@...il.com>
> Reported-by: John Hubbard <jhubbard@...dia.com>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
> ---
>  kernel/memremap.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/memremap.c b/kernel/memremap.c
> index 16141b608b63..ecee37b44aa1 100644
> --- a/kernel/memremap.c
> +++ b/kernel/memremap.c
> @@ -330,7 +330,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);
>  
>  #ifdef CONFIG_DEV_PAGEMAP_OPS
>  DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
> -EXPORT_SYMBOL_GPL(devmap_managed_key);
> +EXPORT_SYMBOL(devmap_managed_key);
>  static atomic_t devmap_enable;
>  
>  /*
> @@ -371,5 +371,5 @@ void __put_devmap_managed_page(struct page *page)
>  	} else if (!count)
>  		__put_page(page);
>  }
> -EXPORT_SYMBOL_GPL(__put_devmap_managed_page);
> +EXPORT_SYMBOL(__put_devmap_managed_page);
>  #endif /* CONFIG_DEV_PAGEMAP_OPS */
> 

Yep, that fixes everything I was seeing.

thanks,
-- 
John Hubbard
NVIDIA