Re: [PATCH 07/11] dasd: don't set the discard_alignment queue limit
- To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
- Cc: Richard Weinberger <richard@nod.at>, Johannes Berg <johannes@sipsolutions.net>, Josef Bacik <josef@toxicpanda.com>, "Md. Haris Iqbal" <haris.iqbal@ionos.com>, Jack Wang <jinpu.wang@ionos.com>, "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>, Roger Pau Monné <roger.pau@citrix.com>, Mike Snitzer <snitzer@kernel.org>, Song Liu <song@kernel.org>, Stefan Haberland <sth@linux.ibm.com>, "Martin K. Petersen" <martin.petersen@oracle.com>, linux-um@lists.infradead.org, linux-block@vger.kernel.org, nbd@other.debian.org, virtualization@lists.linux-foundation.org, xen-devel@lists.xenproject.org, linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org, linux-s390@vger.kernel.org, dm-devel@redhat.com
- Subject: Re: [PATCH 07/11] dasd: don't set the discard_alignment queue limit
- From: Jan Höppner <hoeppner@linux.ibm.com>
- Date: Fri, 6 May 2022 14:56:58 +0200
- Message-id: <[🔎] 1f26f6b4-4d33-6291-31c2-5cb68a5be829@linux.ibm.com>
- In-reply-to: <20220418045314.360785-8-hch@lst.de>
- References: <20220418045314.360785-1-hch@lst.de> <20220418045314.360785-8-hch@lst.de>
On 18/04/2022 06:53, Christoph Hellwig wrote:
> The discard_alignment queue limit is named a bit misleading means the
> offset into the block device at which the discard granularity starts.
> Setting it to PAGE_SIZE while the discard granularity is the block size
> that is smaller or the same as PAGE_SIZE as done by dasd is mostly
> harmless but also useless.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jan Höppner <hoeppner@linux.ibm.com>
Sorry for a rather late answer. I saw that Jens already applied
the patches so it's fine when the Ack isn't added anymore.
Wanted to send it anyway so that you know we're aware of it.
> ---
> drivers/s390/block/dasd_fba.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/s390/block/dasd_fba.c b/drivers/s390/block/dasd_fba.c
> index 8bd5665db9198..60be7f7bf2d16 100644
> --- a/drivers/s390/block/dasd_fba.c
> +++ b/drivers/s390/block/dasd_fba.c
> @@ -782,7 +782,6 @@ static void dasd_fba_setup_blk_queue(struct dasd_block *block)
> blk_queue_segment_boundary(q, PAGE_SIZE - 1);
>
> q->limits.discard_granularity = logical_block_size;
> - q->limits.discard_alignment = PAGE_SIZE;
>
> /* Calculate max_discard_sectors and make it PAGE aligned */
> max_bytes = USHRT_MAX * logical_block_size;
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