On Thu, Mar 8, 2018 at 9:36 PM, Alex Lemberg <Alex.Lemberg@xxxxxxx> 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 these partitions. > 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. Yep. > 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 LUNs. 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 copied. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
