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Date:   Tue, 11 Dec 2018 15:05:49 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Jens Axboe <axboe@kernel.dk>, Hannes Reinecke <hare@suse.com>,
        Paul Mackerras <paulus@ozlabs.org>,
        Juergen Gross <jgross@suse.com>, linux-scsi@vger.kernel.org,
        linux-block@vger.kernel.org
Subject: Re: [PATCH 2/9] scsi: introduce a max_segment_size host_template
 parameters
Message-ID: <20181211140549.GA8473@lst.de>
References: <20181206155258.11465-1-hch@lst.de> <20181206155258.11465-3-hch@lst.de> <20181211020237.GB27651@ming.t460p>
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On Tue, Dec 11, 2018 at 10:02:38AM +0800, Ming Lei wrote:
> Just one concern, max segment size is often related with one specific
> controller's DMA capability.
> 
> Is it possible that HBAs have different segment size, but all are driven
> by same driver(shared scsi_host_template)?

It is support just like most other attributes - by having one variable
in the host template and one in the host, allowing the driver to
override the per-host one between scsi_host_alloc and scsi_add_host.