From: Jens Axboe <axboe@kernel.dk>
To: Jon Derrick <jonathan.derrick@intel.com>
Cc: linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org,
linux-block@vger.kernel.org, keith.busch@intel.com,
hch@infradead.org, sagi@grimberg.me
Subject: Re: [PATCH] nvme/scsi: Consider LBA format in IO splitting calculation
Date: Mon, 24 Apr 2017 22:00:26 -0600 [thread overview]
Message-ID: <20170425040025.GA23572@kernel.dk> (raw)
In-Reply-To: <20170425000243.2019-1-jonathan.derrick@intel.com>
On Mon, Apr 24 2017, Jon Derrick wrote:
> The current command submission code uses a sector-based value when
> considering the maximum number of blocks per command. With a
> 4k-formatted namespace and a command exceeding max hardware limits, this
> calculation doesn't split IOs which should be split and fails in the
> nvme layer. This patch fixes that calculation and enables IO splitting
> in these circumstances.
>
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
> ---
> drivers/nvme/host/scsi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/scsi.c b/drivers/nvme/host/scsi.c
> index f49ae27..988da61 100644
> --- a/drivers/nvme/host/scsi.c
> +++ b/drivers/nvme/host/scsi.c
> @@ -1609,7 +1609,7 @@ static int nvme_trans_do_nvme_io(struct nvme_ns *ns, struct sg_io_hdr *hdr,
> struct nvme_command c;
> u8 opcode = (is_write ? nvme_cmd_write : nvme_cmd_read);
> u16 control;
> - u32 max_blocks = queue_max_hw_sectors(ns->queue);
> + u32 max_blocks = queue_max_hw_sectors(ns->queue) >> (ns->lba_shift - 9);
>
> num_cmds = nvme_trans_io_get_num_cmds(hdr, cdb_info, max_blocks);
Patch looks correct to me, as we always consider the hw sectors settings
in units of 512b blocks.
Reviewed-by: Jens Axboe <axboe@fb.com>
--
Jens Axboe
next prev parent reply other threads:[~2017-04-25 4:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-25 0:02 [PATCH] nvme/scsi: Consider LBA format in IO splitting calculation Jon Derrick
2017-04-25 4:00 ` Jens Axboe [this message]
2017-04-25 4:27 ` Damien Le Moal
2017-04-25 4:32 ` Jens Axboe
2017-04-25 4:43 ` Damien Le Moal
2017-04-25 17:57 ` Christoph Hellwig
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