Message-ID: <46408662.5070003@gmail.com>
Date: Tue, 08 May 2007 16:17:06 +0200
From: Rene Herman <rene.herman@gmail.com>
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To: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Andrew Morton <akpm@osdl.org>, Jens Axboe <jens.axboe@oracle.com>,
       Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: New Mitsumi legacy CD-ROM driver
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On 05/08/2007 03:53 PM, Pekka Enberg wrote:

>> +static int __mitsumi_read_toc(struct mitsumi_cdrom *mcd)
>> +{
>> +       int tracks = mcd->header.cdth_trk1 - mcd->header.cdth_trk0 + 1;
>> +       int retries;
>> +       int err = 0;
>> +
>> +       kfree(mcd->toc);
>> +
>> +       mcd->toc = kzalloc(tracks * sizeof *mcd->toc, GFP_KERNEL);
> 
> Perhaps we should use krealloc() + memset() here?

Earlier I had a patch lined up that checked the previous number of tracks 
against the current number and only freed the TOC array when they were not 
the same. The majority case is a data CD with one TOC entry meaning we just 
reuse the entry. You then have to keep the previous number of tracks though 
and it seemed a little pointless so I dropped it.

Another option is using a linked list for the TOC and reusing or allocating 
nodes upon reading the actual entry from the Q channel and freeing the rest 
when we got them all. Also seemed overly complex and the CDROMREADTOCENTRY 
gets slower ;-)

I admit my DOS inspired dislike of realloc() is largely pointless these days 
but, err... "E426: tag not found: krealloc". Would you perhaps like the 
list? Or the if (tracks != mcd->tracks) thing?

Rene.

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