Re: [PATCH] ata: libata-core: Do not call ata_dev_power_set_standby() twice

[Damien Le Moal <dlemoal@kernel.org>]

On 2/16/24 20:20, Niklas Cassel wrote:
> From: Damien Le Moal <dlemoal@kernel.org>
> 
> For regular system shutdown, ata_dev_power_set_standby() will be
> executed twice: once the scsi device is removed and another when
> ata_pci_shutdown_one() executes and EH completes unloading the devices.
> 
> Make the second call to ata_dev_power_set_standby() do nothing by using
> ata_dev_power_is_active() and return if the device is already in
> standby.
> 
> Fixes: 2da4c5e24e86 ("ata: libata-core: Improve ata_dev_power_set_active()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---
> This fix was originally part of patch that contained both a fix and
> a revert in a single patch:
> https://lore.kernel.org/linux-ide/20240111115123.1258422-3-dlemoal@kernel.org/
> 
> This patch contains the only the fix (as it is valid even without the
> revert), without the revert.
> 
> Updated the Fixes tag to point to a more appropriate commit, since we
> no longer revert any code.
> 
>  drivers/ata/libata-core.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index d9f80f4f70f5..af2334bc806d 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -85,6 +85,7 @@ static unsigned int ata_dev_init_params(struct ata_device *dev,
>  static unsigned int ata_dev_set_xfermode(struct ata_device *dev);
>  static void ata_dev_xfermask(struct ata_device *dev);
>  static unsigned long ata_dev_blacklisted(const struct ata_device *dev);
> +static bool ata_dev_power_is_active(struct ata_device *dev);

I forgot what I did originally but didn't I move the code of
ata_dev_power_is_active() before ata_dev_power_set_standby() to avoid this
forward declaration ?

With that, the code is a little odd as ata_dev_power_is_active() is defined
between ata_dev_power_set_standby() and ata_dev_power_set_active() but both
functions use it...

>  
>  atomic_t ata_print_id = ATOMIC_INIT(0);
>  
> @@ -2017,8 +2018,9 @@ void ata_dev_power_set_standby(struct ata_device *dev)
>  	struct ata_taskfile tf;
>  	unsigned int err_mask;
>  
> -	/* If the device is already sleeping, do nothing. */
> -	if (dev->flags & ATA_DFLAG_SLEEPING)
> +	/* If the device is already sleeping or in standby, do nothing. */
> +	if ((dev->flags & ATA_DFLAG_SLEEPING) ||
> +	    !ata_dev_power_is_active(dev))
>  		return;
>  
>  	/*

-- 
Damien Le Moal
Western Digital Research