[RFC v4 0/3] pstore/rom: new support logger for block devices

[liaoweixiong]

Why should we need pstore_rom?
1. Most embedded intelligent equipment have no persistent ram, which
increases costs. We perfer to cheaper solutions, like block devices.
In fast, there is already a sample for block device logger in driver
MTD (drivers/mtd/mtdoops.c).
2. Do not any equipment have battery, which means that it lost all data
on general ram if power failure. Pstore has little to do for these
equipments.

[PATCH v4]
On patch 1:
1. Fix always true condition '(--i >= 0) => (0-u32max >= 0)' in function
   romz_init_zones by defining variable i to 'int' rahter than
   'unsigned int'.
2. To make codes more easily to read, we use macro READ_NEXT_ZONE for
   return value of romz_dmesg_read if it need to read next zone.
   Moveover, we assign READ_NEXT_ZONE -1024 rather than 0.
3. Add 'FLUSH_META' to 'enum romz_flush_mode' and rename 'NOT_FLUSH' to
   'FLUSH_NONE'
4. Function romz_zone_write work badly with FLUSH_PART mode as badly
   address and offset to write.
On patch 3:
NEW SUPPORT psmg for pstore_rom.

[PATCH v3]
On patch 1:
Fix build as module error for undefined 'vfs_read' and 'vfs_write'
Both of 'vfs_read' and 'vfs_write' haven't be exproted yet, so we use
'kernel_read' and 'kernel_write' instead.

[PATCH v2]
On patch 1:
Fix build as module error for redefinition of 'romz_unregister' and
'romz_register'

[PATCH v1]
On patch 1:
Core codes of pstore_rom, which works well on allwinner(sunxi) platform.
On patch 2:
A sample for pstore_rom, using general ram rather than block device.

liaoweixiong (3):
  pstore/rom: new support logger for block devices
  pstore/rom: add sample for pstore_rom
  pstore/rom: support pmsg for pstore_rom

 fs/pstore/Kconfig          |   16 +
 fs/pstore/Makefile         |    5 +
 fs/pstore/rombuf.c         |   46 ++
 fs/pstore/romzone.c        | 1138 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pstore_rom.h |   62 +++
 5 files changed, 1267 insertions(+)
 create mode 100644 fs/pstore/rombuf.c
 create mode 100644 fs/pstore/romzone.c
 create mode 100644 include/linux/pstore_rom.h

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1.9.1