Hi Ulf, On Mon, Oct 24 2011, Ulf Hansson wrote: > The kernel could very much be used in manufacturing environment as > well. Don't know if and how we should consider this. > > Do you think a change to an ioctl is a better alternative than sysfs? > Then let's change to that!
Ah, we're not proposing a new ioctl for this -- we're proposing that the perm-r/o command could be sent from a userspace binary that *uses* the arbitrary command ioctl that we already have. The arbitrary command ioctl is drivers/mmc/card/block.c:mmc_blk_ioctl_cmd(). Please could you send a version of the patch that supports power-on r/o but not perm r/o, and perhaps also post userspace code for submitting the perm r/o command through the ioctl interface? (Perhaps this code should eventually be submitted to a disk management tool..) Also, it looks like it's possible to set read-only for the whole device, as well as for boot partitions. Could you update the patch to allow setting power-on r/o for the entire card, not just the boot partitions? > Enable boot partitions to be power and permanently read-only locked via > a sysfs entry. There will be one sysfs entry for the main mmc device: > > /sys/block/mmcblkX/boot_partition_ro_lock I don't follow why this node is necessary, instead of just having the nodes in the mmcblkXbootY/ directories. Could you explain? > and one for each boot partition: > > /sys/block/mmcblkXbootY/ro_lock > > The boot partitions are power or permanently locked by writing "pwr_ro" > or "perm_ro" to one of the files. Now that we're only having one type of r/o lock, let's do: echo 1 > /sys/block/mmcblkXbootY/ro_lock_until_next_power_on to lock just a boot partition, and: echo 1 > /sys/block/mmcblkX/ro_lock_until_next_power_on to lock the entire card (which will cover the boot partition too), with echo 0 to unlock. Other review comments: I noticed that your pr_*(); statements are missing "\n"s on the end, and you should add documentation on the new sysfs nodes to: Documentation/mmc/mmc-dev-parts.txt I think the overlap between your patch and Andrei's mmcblkXbootY/force_ro node is going to be confusing -- one operates purely in the kernel and the other is sent to the card. Do you have any proposal for making the difference clearer? Thanks, - Chris. -- Chris Ball <c...@laptop.org> <http://printf.net/> One Laptop Per Child -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
