Re: [PATCH] ide: ide_port_wait_ready() fix

[David Miller]

From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Date: Wed, 12 Oct 2011 16:59:55 +0200

> David Miller wrote:
> 
>> From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
>> Date: Tue, 11 Oct 2011 19:13:18 +0200
>> 
>> > From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
>> > Subject: [PATCH] ide: ide_port_wait_ready() fix
>> > 
>> > Fix for commit a20b2a4 ("ide: skip probe if there are no devices on
>> > the port (v2)").  We must check for slave device before failing.
>> > 
>> > Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
>> 
>> This will mishandle the case where there is no slave in the device
>> list.
> 
> I don't see it:
> 
> @ -598,7 +598,7 @@ static int ide_port_wait_ready(ide_hwif_
>  {
>  	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
>  	ide_drive_t *drive;
> -	int i, rc;
> +	int i, rc, prev_rc = 0;
>  
>  	printk(KERN_DEBUG "Probing IDE interface %s...\n", hwif->name);
>  
> @@ -623,8 +623,10 @@ static int ide_port_wait_ready(ide_hwif_
>  			tp_ops->write_devctl(hwif, ATA_DEVCTL_OBS);
>  			mdelay(2);
>  			rc = ide_wait_not_busy(hwif, 35000);
> -			if (rc)
> +			if (prev_rc && rc)
>  				goto out;
> +			prev_rc = rc;
> +			rc = 0;
>  		} else
>  			printk(KERN_DEBUG "%s: ide_wait_not_busy() skipped\n",
>  					  drive->name);
> 
> If there is no slave device but there is a master device the code falls-through
> and returns a success.

That's not what we want, if there is only a master device and no slave device
in the list this loop is iterating over we want to return the error code
in "rc", not zero.
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