RE: [virtio-dev] [PATCH] virtio-blk: add DISCARD support to virtio-blk driver

[Liu, Changpeng]

> -----Original Message-----
> From: virtio-dev@xxxxxxxxxxxxxxxxxxxx [mailto:virtio-dev@xxxxxxxxxxxxxxxxxxxx] On
> Behalf Of Paolo Bonzini
> Sent: Monday, March 27, 2017 7:34 PM
> To: Liu, Changpeng <changpeng.liu@xxxxxxxxx>; virtio-dev@xxxxxxxxxxxxxxxxxxxx;
> virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; hch@xxxxxx
> Cc: qemu-devel@xxxxxxxxxx
> Subject: Re: [virtio-dev] [PATCH] virtio-blk: add DISCARD support to virtio-blk driver
> 
> 
> 
> On 28/03/2017 10:39, Changpeng Liu wrote:
> > +	if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
> > +		q->limits.discard_zeroes_data = 0;
> 
> Maybe you could use another feature bit to populate discard_zeroes_data.
> 
> Paolo
> 
Sounds good to me, Christoph Hellwig mentioned this field will be removed in next release, just removed this line makes clear.
> > +		q->limits.discard_alignment = blk_size;
> > +		q->limits.discard_granularity = blk_size;
> > +		blk_queue_max_discard_sectors(q, UINT_MAX);
> > +		blk_queue_max_discard_segments(q, 1);
> > +		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
> > +	}
> > +
> 
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