Re: [patch 3/5] Add MMC password protection (lock/unlock) support V3

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Wed, Jan 11, 2006 at 09:58:03AM -0400, Anderson Briglia wrote:
> Anderson Briglia wrote:
> > Russell King wrote:
> > 
> > 
> >>On Mon, Jan 09, 2006 at 06:16:02PM -0400, Anderson Briglia wrote:
> >> 
> >>
> >>
> >>>+	dev = bus_find_device(&mmc_bus_type, NULL, NULL, mmc_match_lockable);
> >>>+	if (!dev)
> >>>+		goto error;
> >>>+	card = dev_to_mmc_card(dev);
> >>>+	
> >>>+	if (operation == KEY_OP_INSTANTIATE) { /* KEY_OP_INSTANTIATE */
> >>>+               if (mmc_card_locked(card)) {
> >>>+                       ret = mmc_lock_unlock(card, key, MMC_LOCK_MODE_UNLOCK);
> >>>+                       mmc_remove_card(card);
> >>>+                       mmc_register_card(card);
> >>>+               }
> >>>+	       else
> >>>+		       ret = mmc_lock_unlock(card, key, MMC_LOCK_MODE_SET_PWD);
> >>>   
> > 
> >>Also, removing and re-registering a card is an offence.  These
> >>things are ref-counted, and mmc_remove_card() will drop the last
> >>reference - so the memory associated with it will be freed.  Then
> >>you re-register it.  Whoops.
> >>
> >>If you merely want to try to attach a driver, use device_attach()
> >>instead.
> >>
> We changed the mmc_remove_card() and mmc_register_card() by
> device_release_driver() and device_attach(), supposedly avoiding
> ref-counts issues.

As per my previous mail - I think this probably comes down to differences
between mainline and the omap tree.  My suggestion should work fine
in mainline.  I can only suspect that the OMAP tree is doing something
it shouldn't.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core
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