linux-kernel - Re: [PATCH]drivers/ata/libata-eh.c:1509 unneeded memset()

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Message-ID: <4B4799FB.9030208@googlemail.com>
Date:	Fri, 08 Jan 2010 21:47:55 +0100
From:	René Bolldorf <xsecute@...glemail.com>
To:	James Bottomley <James.Bottomley@...e.de>
CC:	Jeff Garzik <jgarzik@...ox.com>, linux-ide@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-scsi <linux-scsi@...r.kernel.org>
Subject: Re: [PATCH]drivers/ata/libata-eh.c:1509 unneeded memset()

On 01/08/10 16:28, James Bottomley wrote:
> On Thu, 2010-01-07 at 14:15 -0500, Jeff Garzik wrote:
>> On 12/30/2009 05:59 PM, René Bolldorf wrote:
>>> We don't need this ;-).
>>>
>>> Best regards René Bolldorf&  a happy new year in advance.
>>>
>>> --- ./drivers/ata/libata-eh.c 2009-12-30 23:44:05.578988545 +0100
>>> +++ ./drivers/ata/libata-eh.c 2009-12-30 23:45:06.991987607 +0100
>>> @@ -1505,9 +1505,6 @@ static unsigned int atapi_eh_request_sen
>>>
>>> DPRINTK("ATAPI request sense\n");
>>>
>>> - /* FIXME: is this needed? */
>>> - memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);
>>
>> I need a little bit more detail than an unqualified statement...  Did
>> you audit all paths leading to this code point?
>
> There are two code paths coming into here.  One directly from the scsi
> sense buffer:
>
> 		if (!(qc->ap->pflags&  ATA_PFLAG_FROZEN)) {
> 			tmp = atapi_eh_request_sense(qc->dev,
> 						qc->scsicmd->sense_buffer,
> 						qc->result_tf.feature>>  4);
>
> Which is fine because SCSI zeros the sense buffer.
>
> But one also here:
>
> 		u8 *sense_buffer = dev->link->ap->sector_buf;
> 		[...]
> 		err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
>
> Which doesn't look OK because it looks like the sector_buf isn't cleared
> (and it is reused).
>
> James
>
>

Thank's, you're right. I have overseen this, sry for that.
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