On Thu, Mar 8, 2018 at 9:36 PM, Alex Lemberg <alex.lemb...@wdc.com> wrote:
> On 3/2/18 4:53 AM, Linus Walleij wrote:
>> What we need to do is make the "special partitions" part of the
>> main block device and stop spawning these special block
>> devices for each boot partions or general partitions. In addition,
>> each of these boot partitions or general partitions will get their
>> own block queue and state container which is not cheap in
>> runtime memory footprint terms.
>> So what I want to do (unless someone beats me to it) it to come
>> up with some way making boot and general partitions part
>> of the main block device. Possibly the core kernel partitioning
>> code needs to be augmented. The tentative idea is to just
>> put the sectors representing these partitions after the main
>> block device and access them from there, with an offset.
> I don't think that hiding the Boot and RPMB will resolve the problem
> described above.
Me neither. I'm just trying to discuss the problem lurking behind
> Boot partition (same as RPMB) in eMMC device is a separate
> "physical" partition.
> It has its own logical address range and different from general
> partition characteristics.
> From the protocol - the access to this partition it requires switch
> partition command.
Yeah I saw that as well... it's a bit funny.
> From the device side - it can be managed in totally different manner
> (SLC vs. MLC blocks, etc.)
> I think it completely makes sense to allow access to Boot partition from the
> user space. For example - to allow R/W the boot image.
But this patch doesn't hide the partition from userspace does it?
They will still appear in /dev/mmcblk0boot1 etc.
Just not reported as "real" partitions in /proc/partitions.
Or do I misunderstand it?
> AFAIK, in case of SCSI/UFS devices - Boot LUN's are represented as
> separate block
> device partitions (/dev/sdb, dev/sdc...).
> Shouldn't we have the same for eMMC?
I think we should, but we have the problem with the boot partitions
and general partitions that they do not work anything like SCSCI
On a SCSI device dd from the whole device will copy all data on
the device, the partition table and contents of all partitions.
For say /dev/mmcblk0 this is not true of the device contains
boot or general partitions, those other partitions will not be