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Date: Thu, 18 Nov 2010 17:28:44 +0100
From: Hannes Reinecke <hare@suse.de>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Re: [PATCH 09/16] scsi-disk: Allocate iovec
	dynamically
References: <20101118144723.61032F90AB@ochil.suse.de>
	<4CE54755.8010205@redhat.com>
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To: Gerd Hoffmann <kraxel@redhat.com>
Cc: stefanha@gmail.com, qemu-devel@nongnu.org, nab@linux-iscsi.org

On 11/18/2010 04:33 PM, Gerd Hoffmann wrote:
>   Hi,
>=20
>> +static size_t scsi_req_iov_len(SCSIDiskReq *r)
>> +{
>> +    size_t iov_len =3D 0;
>> +    int i;
>> +
>> +    for (i =3D 0; i<  r->iov_num; i++)
>> +        iov_len +=3D r->iov[i].iov_len;
>> +
>> +    return iov_len;
>> +}
>=20
> You are aware that there is a QEMUIOVector type with helper functions
> which keeps track of both number of elements and total size?
>=20
Yes. But I'm passing passing in an entire iovec to the request.
However, the QEMUIOVector routines allow you to add only _one_
element at a time, which is pretty wasteful here.

And I'm counting the resulting length of the iovec, which might have
been changed by read/write operations. For which there is no generic
function either.

But if requested I could easily move it into cutils.c.

Cheers,

Hannes
--=20
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg
GF: Markus Rex, HRB 16746 (AG N=FCrnberg)