From: hch@infradead.org (Christoph Hellwig)
Subject: [PATCH] nvme: set discard_alignment to zero
Date: Tue, 28 Nov 2017 04:38:13 -0800 [thread overview]
Message-ID: <20171128123812.GB1736@infradead.org> (raw)
In-Reply-To: <20171124153053.23056-1-ddiss@suse.de>
Adding Jens, who added this code, but it looks fine to me.
On Fri, Nov 24, 2017@04:30:53PM +0100, David Disseldorp wrote:
> Similar to 7c084289795b ("rbd: set discard_alignment to zero"), NVMe
> devices are currently incorrectly initialised with the block queue
> discard_alignment set to the NVMe stream alignment.
>
> As per Documentation/ABI/testing/sysfs-block:
> The discard_alignment parameter indicates how many bytes the beginning
> of the device is offset from the internal allocation unit's natural
> alignment.
>
> Correcting the discard_alignment parameter to zero has no effect on how
> discard requests are propagated through the block layer - @alignment in
> __blkdev_issue_discard() remains zero. However, it does fix other
> consumers, such as LIO's Block Limits VPD response.
>
> Signed-off-by: David Disseldorp <ddiss at suse.de>
> ---
> drivers/nvme/host/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 25da74d310d1..2e224ab5c340 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -1287,7 +1287,7 @@ static void nvme_config_discard(struct nvme_ctrl *ctrl,
> BUILD_BUG_ON(PAGE_SIZE / sizeof(struct nvme_dsm_range) <
> NVME_DSM_MAX_RANGES);
>
> - queue->limits.discard_alignment = size;
> + queue->limits.discard_alignment = 0;
> queue->limits.discard_granularity = size;
>
> blk_queue_max_discard_sectors(queue, UINT_MAX);
> --
> 2.13.6
>
>
> _______________________________________________
> Linux-nvme mailing list
> Linux-nvme at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-nvme
---end quoted text---
next prev parent reply other threads:[~2017-11-28 12:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-24 15:30 [PATCH] nvme: set discard_alignment to zero David Disseldorp
2017-11-28 12:38 ` Christoph Hellwig [this message]
2017-12-01 22:15 ` Jens Axboe
2017-11-30 17:40 ` Martin K. Petersen
2017-12-04 20:20 ` Christoph Hellwig
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