Re: [PATCH 1/2] libata: Introduce ata_platform_shutdown_one()

[Tejun Heo <tj@kernel.org>]

On Mon, Jul 03, 2017 at 02:02:41PM -0400, Nate Watterson wrote:
> In similar fashion to how ata_platform_remove_one() is used, this
> newly introduced method can be used by platform ata drivers to get
> basic shutdown functionality (stopping host DMA and interrupts).
> 
> Signed-off-by: Nate Watterson <nwatters@codeaurora.org>
> ---
>  drivers/ata/libata-core.c | 20 ++++++++++++++++++++
>  include/linux/libata.h    |  1 +
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index e157a0e..537932e 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -6702,6 +6702,25 @@ int ata_platform_remove_one(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +/**
> + *	ata_platform_shutdown_one - Platform layer callback for device shutdown
> + *	@pdev: Platform device being shutdown
> + *
> + *	Platform layer indicates to libata via this hook that shutdown is
> + *	in progress and the input device should be quiesced. Functionally this
                            ^^^^^
> + *	is equivalent to ata_platform_remove_one(), however devres_release_all()
> + *	is not called on the shutdown path as it is for remove so releasing the
> + *	resources associated with the device must instead be initiated directly.

I can't easily understand the above comment.  Can you please try to
rephrase it so that it's clear why and when it's used?

Thanks.

-- 
tejun