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Date: Mon, 22 Nov 2010 12:26:01 +0100
From: Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] [PATCH 15/16] scsi: Implement get_req_iov callback
Message-ID: <20101122112601.GC1579@lst.de>
References: <20101118144750.9A528F90AB@ochil.suse.de>
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To: Hannes Reinecke <hare@suse.de>
Cc: stefanha@gmail.com, qemu-devel@nongnu.org, nab@linux-iscsi.org, kraxel@redhat.com

> @@ -95,14 +95,30 @@ static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag,
>      return req;
>  }
>  
> +static SCSIRequest *scsi_new_request_iovec(SCSIDevice *d, uint32_t tag,
> +        uint32_t lun, struct iovec *iov, int iov_num)
> +{
> +    SCSIRequest *req;
> +    SCSIDiskReq *r;
> +
> +    req = scsi_req_alloc(sizeof(SCSIDiskReq), d, tag, lun);
> +    r = DO_UPCAST(SCSIDiskReq, req, req);
> +    r->iov = iov;
> +    r->iov_num = iov_num;
> +    r->iov_buf = NULL;
> +    return req;
> +}

While the amount of duplicated code here is rather small I still hate
the duplication.

The simplest step is to implement scsi_new_request on top of
scsi_new_request_iovec by just allocation the iovec in scsi_new_request
and passing it to scsi_new_request_iovec.  The next patch on top would
be to move the iovec allocation to the HBA driver and only stick to
one interface.