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Re: [Qemu-devel] Re: [PATCH 09/16] scsi-disk: Allocate iovec dynamically
From: |
Hannes Reinecke |
Subject: |
Re: [Qemu-devel] Re: [PATCH 09/16] scsi-disk: Allocate iovec dynamically |
Date: |
Thu, 18 Nov 2010 17:28:44 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101026 SUSE/3.0.10 Thunderbird/3.0.10 |
On 11/18/2010 04:33 PM, Gerd Hoffmann wrote:
> Hi,
>
>> +static size_t scsi_req_iov_len(SCSIDiskReq *r)
>> +{
>> + size_t iov_len = 0;
>> + int i;
>> +
>> + for (i = 0; i< r->iov_num; i++)
>> + iov_len += r->iov[i].iov_len;
>> +
>> + return iov_len;
>> +}
>
> You are aware that there is a QEMUIOVector type with helper functions
> which keeps track of both number of elements and total size?
>
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
--
Dr. Hannes Reinecke zSeries & Storage
address@hidden +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)