Re: [PATCH v5 4/7] ata: libata: cleanup fua support detection

From: Chaitanya Kulkarni <chaitanyak@nvidia.com>
To: Damien Le Moal <damien.lemoal@opensource.wdc.com>,
	"linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	Jens Axboe <axboe@kernel.dk>
Cc: "Maciej S . Szmigiero" <mail@maciej.szmigiero.name>,
	Hannes Reinecke <hare@suse.de>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v5 4/7] ata: libata: cleanup fua support detection
Date: Mon, 7 Nov 2022 05:44:20 +0000	[thread overview]
Message-ID: <c9abd10e-c1fc-a111-f2fa-c5d39ceb03f4@nvidia.com> (raw)
In-Reply-To: <20221107005021.1327692-5-damien.lemoal@opensource.wdc.com>

On 11/6/2022 4:50 PM, Damien Le Moal wrote:
> Move the detection of a device FUA support from
> ata_scsiop_mode_sense()/ata_dev_supports_fua() to device scan time in
> ata_dev_configure().
> 
> The function ata_dev_config_fua() is introduced to detect if a device
> supports FUA and this support is indicated using the new device flag
> ATA_DFLAG_FUA.
> 
> In order to blacklist known buggy devices, the horkage flag
> ATA_HORKAGE_NO_FUA is introduced. Similarly to other horkage flags, the
> libata.force= arguments "fua" and "nofua" are also introduced to allow
> a user to control this horkage flag through the "force" libata
> module parameter.
> 
> The ATA_DFLAG_FUA device flag is set only and only if all the following
> conditions are met:
> * libata.fua module parameter is set to 1
> * The device supports the WRITE DMA FUA EXT command,
> * The device is not marked with the ATA_HORKAGE_NO_FUA flag, either from
>    the blacklist or set by the user with libata.force=nofua
> * The device supports NCQ (while this is not mandated by the standards,
>    this restriction is introduced to avoid problems with older non-NCQ
>    devices).
> 
> Enabling or diabling libata FUA support for all devices can now also be
> done using the "force=[no]fua" module parameter when libata.fua is set
> to 1.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Reviewed-by: Hannes Reinecke <hare@suse.de>
> ---


Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

-ck