kernel: support FIT partition parser on mtdblock devices

Allow using the FIT block-device partition partition parser to work on
top of mtdblock devices.
This is more tricky than it sounds as it requires to reorganize the
procedure of registering mtdblock devices in order to avoid locking
troubles caused by the block partition parsers then trying to open
the mtdblock device for reading while locks are still being held.
Fix that by moving the adding of the disks after the entire device
has been probed when locks no longer need to be held.
Also address issue with mtdsuper surfaced when using sub-partitions
which prevented mounting JFFS2 using the /dev/mtdblock* device.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

1 files changed, 219 insertions, 0 deletions

diff --git a/target/linux/generic/hack-5.10/410-block-fit-partition-parser.patch b/target/linux/generic/hack-5.10/410-block-fit-partition-parser.patch
new file mode 100644
index 0000000000..2528f3afa1
--- /dev/null
+++ b/target/linux/generic/hack-5.10/410-block-fit-partition-parser.patch
@@ -0,0 +1,219 @@
+--- a/block/blk.h
++++ b/block/blk.h
+@@ -357,6 +357,7 @@ char *disk_name(struct gendisk *hd, int
+ #define ADDPART_FLAG_NONE	0
+ #define ADDPART_FLAG_RAID	1
+ #define ADDPART_FLAG_WHOLEDISK	2
++#define ADDPART_FLAG_ROOTDEV	4
+ void delete_partition(struct hd_struct *part);
+ int bdev_add_partition(struct block_device *bdev, int partno,
+ 		sector_t start, sector_t length);
+--- a/block/partitions/Kconfig
++++ b/block/partitions/Kconfig
+@@ -101,6 +101,13 @@ config ATARI_PARTITION
+ 	  Say Y here if you would like to use hard disks under Linux which
+ 	  were partitioned under the Atari OS.
+ 
++config FIT_PARTITION
++	bool "Flattened-Image-Tree (FIT) partition support" if PARTITION_ADVANCED
++	default n
++	help
++	  Say Y here if your system needs to mount the filesystem part of
++	  a Flattened-Image-Tree (FIT) image commonly used with Das U-Boot.
++
+ config IBM_PARTITION
+ 	bool "IBM disk label and partition support"
+ 	depends on PARTITION_ADVANCED && S390
+--- a/block/partitions/Makefile
++++ b/block/partitions/Makefile
+@@ -8,6 +8,7 @@ obj-$(CONFIG_ACORN_PARTITION) += acorn.o
+ obj-$(CONFIG_AMIGA_PARTITION) += amiga.o
+ obj-$(CONFIG_ATARI_PARTITION) += atari.o
+ obj-$(CONFIG_AIX_PARTITION) += aix.o
++obj-$(CONFIG_FIT_PARTITION) += fit.o
+ obj-$(CONFIG_CMDLINE_PARTITION) += cmdline.o
+ obj-$(CONFIG_MAC_PARTITION) += mac.o
+ obj-$(CONFIG_LDM_PARTITION) += ldm.o
+--- a/block/partitions/check.h
++++ b/block/partitions/check.h
+@@ -58,6 +58,7 @@ int amiga_partition(struct parsed_partit
+ int atari_partition(struct parsed_partitions *state);
+ int cmdline_partition(struct parsed_partitions *state);
+ int efi_partition(struct parsed_partitions *state);
++int fit_partition(struct parsed_partitions *state);
+ int ibm_partition(struct parsed_partitions *);
+ int karma_partition(struct parsed_partitions *state);
+ int ldm_partition(struct parsed_partitions *state);
+@@ -68,3 +69,5 @@ int sgi_partition(struct parsed_partitio
+ int sun_partition(struct parsed_partitions *state);
+ int sysv68_partition(struct parsed_partitions *state);
+ int ultrix_partition(struct parsed_partitions *state);
++
++int parse_fit_partitions(struct parsed_partitions *state, u64 start_sector, u64 nr_sectors, int *slot, int add_remain);
+--- a/block/partitions/core.c
++++ b/block/partitions/core.c
+@@ -10,6 +10,10 @@
+ #include <linux/vmalloc.h>
+ #include <linux/blktrace_api.h>
+ #include <linux/raid/detect.h>
++#ifdef CONFIG_FIT_PARTITION
++#include <linux/root_dev.h>
++#endif
++
+ #include "check.h"
+ 
+ static int (*check_part[])(struct parsed_partitions *) = {
+@@ -46,6 +50,9 @@ static int (*check_part[])(struct parsed
+ #ifdef CONFIG_EFI_PARTITION
+ 	efi_partition,		/* this must come before msdos */
+ #endif
++#ifdef CONFIG_FIT_PARTITION
++	fit_partition,
++#endif
+ #ifdef CONFIG_SGI_PARTITION
+ 	sgi_partition,
+ #endif
+@@ -215,6 +222,18 @@ static ssize_t part_discard_alignment_sh
+ 				p->start_sect));
+ }
+ 
++static ssize_t part_name_show(struct device *dev,
++			      struct device_attribute *attr, char *buf)
++{
++	struct hd_struct *p = dev_to_part(dev);
++
++	if (p->info && p->info->volname)
++		return sprintf(buf, "%s\n", p->info->volname);
++
++	buf[0] = '\0';
++	return 0;
++}
++
+ static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
+ static DEVICE_ATTR(start, 0444, part_start_show, NULL);
+ static DEVICE_ATTR(size, 0444, part_size_show, NULL);
+@@ -223,6 +242,7 @@ static DEVICE_ATTR(alignment_offset, 044
+ static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
+ static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
+ static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
++static DEVICE_ATTR(name, 0444, part_name_show, NULL);
+ #ifdef CONFIG_FAIL_MAKE_REQUEST
+ static struct device_attribute dev_attr_fail =
+ 	__ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
+@@ -237,6 +257,7 @@ static struct attribute *part_attrs[] =
+ 	&dev_attr_discard_alignment.attr,
+ 	&dev_attr_stat.attr,
+ 	&dev_attr_inflight.attr,
++	&dev_attr_name.attr,
+ #ifdef CONFIG_FAIL_MAKE_REQUEST
+ 	&dev_attr_fail.attr,
+ #endif
+@@ -694,6 +715,11 @@ static bool blk_add_partition(struct gen
+ 	    (state->parts[p].flags & ADDPART_FLAG_RAID))
+ 		md_autodetect_dev(part_to_dev(part)->devt);
+ 
++#ifdef CONFIG_FIT_PARTITION
++	if ((state->parts[p].flags & ADDPART_FLAG_ROOTDEV) && ROOT_DEV == 0)
++		ROOT_DEV = part_to_dev(part)->devt;
++#endif
++
+ 	return true;
+ }
+ 
+--- a/drivers/mtd/ubi/block.c
++++ b/drivers/mtd/ubi/block.c
+@@ -396,7 +396,11 @@ int ubiblock_create(struct ubi_volume_in
+ 	dev->leb_size = vi->usable_leb_size;
+ 
+ 	/* Initialize the gendisk of this ubiblock device */
++#ifdef CONFIG_FIT_PARTITION
++	gd = alloc_disk(0);
++#else
+ 	gd = alloc_disk(1);
++#endif
+ 	if (!gd) {
+ 		pr_err("UBI: block: alloc_disk failed\n");
+ 		ret = -ENODEV;
+@@ -413,6 +417,9 @@ int ubiblock_create(struct ubi_volume_in
+ 		goto out_put_disk;
+ 	}
+ 	gd->private_data = dev;
++#ifdef CONFIG_FIT_PARTITION
++	gd->flags |= GENHD_FL_EXT_DEVT;
++#endif
+ 	sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
+ 	set_capacity(gd, disk_capacity);
+ 	dev->gd = gd;
+--- a/block/partitions/efi.c
++++ b/block/partitions/efi.c
+@@ -706,6 +706,9 @@ int efi_partition(struct parsed_partitio
+ 	gpt_entry *ptes = NULL;
+ 	u32 i;
+ 	unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
++#ifdef CONFIG_FIT_PARTITION
++	u32 extra_slot = 64;
++#endif
+ 
+ 	if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
+ 		kfree(gpt);
+@@ -739,6 +742,11 @@ int efi_partition(struct parsed_partitio
+ 				ARRAY_SIZE(ptes[i].partition_name));
+ 		utf16_le_to_7bit(ptes[i].partition_name, label_max, info->volname);
+ 		state->parts[i + 1].has_info = true;
++#ifdef CONFIG_FIT_PARTITION
++		/* If this is a U-Boot FIT volume it may have subpartitions */
++		if (!efi_guidcmp(ptes[i].partition_type_guid, PARTITION_LINUX_FIT_GUID))
++			(void) parse_fit_partitions(state, start * ssz, size * ssz, &extra_slot, 1);
++#endif
+ 	}
+ 	kfree(ptes);
+ 	kfree(gpt);
+--- a/block/partitions/efi.h
++++ b/block/partitions/efi.h
+@@ -52,6 +52,9 @@
+ #define PARTITION_LINUX_LVM_GUID \
+     EFI_GUID( 0xe6d6d379, 0xf507, 0x44c2, \
+               0xa2, 0x3c, 0x23, 0x8f, 0x2a, 0x3d, 0xf9, 0x28)
++#define PARTITION_LINUX_FIT_GUID \
++    EFI_GUID( 0xcae9be83, 0xb15f, 0x49cc, \
++              0x86, 0x3f, 0x08, 0x1b, 0x74, 0x4a, 0x2d, 0x93)
+ 
+ typedef struct _gpt_header {
+ 	__le64 signature;
+--- a/drivers/mtd/mtdblock.c
++++ b/drivers/mtd/mtdblock.c
+@@ -334,7 +334,11 @@ static void mtdblock_remove_dev(struct m
+ static struct mtd_blktrans_ops mtdblock_tr = {
+ 	.name		= "mtdblock",
+ 	.major		= MTD_BLOCK_MAJOR,
++#ifdef CONFIG_FIT_PARTITION
++	.part_bits	= 1,
++#else
+ 	.part_bits	= 0,
++#endif
+ 	.blksize 	= 512,
+ 	.open		= mtdblock_open,
+ 	.flush		= mtdblock_flush,
+--- a/drivers/mtd/mtd_blkdevs.c
++++ b/drivers/mtd/mtd_blkdevs.c
+@@ -407,18 +407,8 @@ int add_mtd_blktrans_dev(struct mtd_blkt
+ 	gd->first_minor = (new->devnum) << tr->part_bits;
+ 	gd->fops = &mtd_block_ops;
+ 
+-	if (tr->part_bits)
+-		if (new->devnum < 26)
+-			snprintf(gd->disk_name, sizeof(gd->disk_name),
+-				 "%s%c", tr->name, 'a' + new->devnum);
+-		else
+-			snprintf(gd->disk_name, sizeof(gd->disk_name),
+-				 "%s%c%c", tr->name,
+-				 'a' - 1 + new->devnum / 26,
+-				 'a' + new->devnum % 26);
+-	else
+-		snprintf(gd->disk_name, sizeof(gd->disk_name),
+-			 "%s%d", tr->name, new->devnum);
++	snprintf(gd->disk_name, sizeof(gd->disk_name),
++		 "%s%d", tr->name, new->devnum);
+ 
+ 	set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
+