linux-kernel - Re: O2micro smartcard reader driver.

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Date:	Tue, 12 Dec 2006 22:28:47 +0100
From:	Eric Piel <Eric.Piel@...mplin-utc.net>
To:	Oliver Neukum <oliver@...kum.org>
CC:	linux-kernel@...r.kernel.org
Subject: Re: O2micro smartcard reader driver.

28.11.2006 12:49, Oliver Neukum wrote/a écrit:
>> Latest version I've published is there:
>> http://pieleric.free.fr/o2scr/
> 
>         case OZSCR_OPEN: /* Request ICC */
>             dprintk("OZSCR_OPEN\n");
>             ATRLength = ATR_SIZE;
>             pRdrExt->IOBase = (PSCR_REGISTERS *) dev->io_base; //XXX necessary?
>             pRdrExt->membase = dev->am_base; //XXX necessary?
> 
>             pRdrExt->m_SCard.AvailableProtocol = 0;
>             pRdrExt->m_SCard.RqstProtocol = 0;
>             dprintk("membase:%p\n", pRdrExt->membase);
>             dprintk("ioport:0x%03x\n", (unsigned)pRdrExt->IOBase);
> 
>             ret = CmdResetReader( pRdrExt, FALSE, ATRBuffer, &ATRLength );
>             apdu.LengthOut = ATRLength;
> 
> #ifdef PCMCIA_DEBUG
>             printk(KERN_DEBUG "Open finished, ATR buffer = ");
>             for( ATRLength = 0; ATRLength < apdu.LengthOut; ATRLength++ )
>                 printk(" [%02X] ", ATRBuffer[ATRLength] );
>             printk("\n");
> #endif
> 
>             memcpy( apdu.DataOut, ATRBuffer, ATRLength );
>             ret = copy_to_user((struct ozscr_apdu *)arg, &apdu, sizeof(struct ozscr_apdu));
>             break;
> 
> 1. This needs locking against concurrent ioctls
> 2. The interpretation of copy_to_user()'s return code is incorrect
> 

Hi Oliver,

Thanks a lot for reading my code, I didn't even hope that someone would! 
I've corrected the copy_to_user (and copy_from_user) code. However I 
don't know how to do locking for the concurrent ioctls. Indeed, I don't 
think there is anything preventing two programs to call the driver at 
the same time. Unfortunately, I've got no idea how to do the locking and 
surprisingly couldn't find any ioctl code in the kernel doing locking. 
Maybe I've just not looked at the right place, could you give a me some 
hint how to do locking for ioctl's ?

See you,
Eric

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