Re: [PATCH v3 3/3] libata: Add support for queued DSM TRIM

[Tejun Heo <tj@kernel.org>]

Hello,

On Thu, Aug 08, 2013 at 09:49:12PM -0700, Marc C wrote:
> +	if (ata_ncq_enabled(dev) &&
> +	    (dev->ncq_send_recv_cmds[ATA_LOG_NCQ_SEND_RECV_DSM_OFFSET] &
> +	     ATA_LOG_NCQ_SEND_RECV_DSM_TRIM)) {

Can you add a feature test macro for this?

> +		/* Newer devices support queued TRIM commands */
> +		tf->protocol = ATA_PROT_NCQ;
> +		tf->command = ATA_CMD_FPDMA_SEND;
> +		tf->hob_nsect = ATA_SUBCMD_FPDMA_SEND_DSM & 0x1f;
> +		tf->nsect = qc->tag << 3;
> +		tf->hob_feature = (size / 512) >> 8;
> +		tf->feature = size / 512;
> +
> +		qc->auxiliary = 1;
> +	} else {
> +		tf->protocol = ATA_PROT_DMA;
> +		tf->hob_feature = 0;
> +		tf->feature = ATA_DSM_TRIM;
> +		tf->hob_nsect = (size / 512) >> 8;
> +		tf->nsect = size / 512;
> +		tf->command = ATA_CMD_DSM;

So, there are controllers which actually look at the command code and
thus will choke on new commands and just looking at whether the device
supports the new commands is likely to be insufficient.  Have you
tested this?  If so, on which controllers / devices?  We're likely to
need whitelisting on controller side, I think.

Thanks.

-- 
tejun