UBI: Add fastmap on-flash data structures

Add the on-flash data structures neeed by fastmap
to ubi-media.h

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Add fastmap stuff to ubi.h

This patch adds fastmap specific data structures to ubi.h.
It moves also struct ubi_work to ubi.h as it is now needed
for more than one c file.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Export next_sqnum()

Fastmap needs next_sqnum(), rename it to ubi_next_sqnum()
and make it non-static.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Add self_check_eba()

self_check_eba() compares two ubi_attach_info objects.
Fastmap uses this function for self checks.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Add fastmap bits to build.c

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Wire-up ->fm_sem

Fastmap uses ->fm_sem to stop EBA changes while writing
a new fastmap.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Add fastmap stuff to attach.c

- Export compare_lebs() as fastmap needs this function.
- Implement fastmap scan logic.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Add fastmap support to the WL sub-system

To make fastmap possible the WL sub-system needs some
changes.
Mostly to support fastmaps pools.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Add fastmap core

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBI: Wire-up fastmap

Make fastmap known to Kconfig, UBI Makefile and MAINTAINERS.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Merge tag 'upstream-3.7-rc1-fastmap' of git://git.infradead.org/linux-ubi

Pull UBI fastmap changes from Artem Bityutskiy:
 "This pull request contains the UBI fastmap support implemented by
  Richard Weinberger from Linutronix.  Fastmap is designed to address
  UBI's slow scanning issues.  Namely, it introduces a new on-flash
  data-structure called "fastmap", which stores the information about
  logical<->physical eraseblocks mappings.  So now to get this
  information just read the fastmap, instead of doing full scan.  More
  information here can be found in Richard's announcement in LKML
  (Subject: UBI: Fastmap request for inclusion (v19)):

     http://thread.gmane.org/gmane.linux.kernel/1364922/focus=1369109

  One thing I want to explicitly say is that fastmap did not have large
  enough linux-next exposure.  It is partially my fault - I did not
  respond quickly enough.  I _really_ apologize for this.  But it had
  good testing and disabled by default, so I do not expect that we'll
  break anything.

  Fastmap is declared as experimental so far, and it is off by default.
  We did declare that the on-flash format may be changed.  The reason
  for this is that no one used it in real production so far, so there is
  a high risk that something is missing.  Besides, we do not have
  user-space tools supporting fastmap so far.

  Nevertheless, I suggest we merge this feature.  Many people want UBI's
  scanning bottleneck to be fixed and merging fastmap now should
  accelerate its production use.  The plan is to make it bullet-prove,
  somewhat clean-up, and make it the default for UBI.  I do not know how
  many kernel releases will it take.

  Basically, I what I want to do for fastmap is something like Linus did
  for btrfs few years ago."

* tag 'upstream-3.7-rc1-fastmap' of git://git.infradead.org/linux-ubi:
  UBI: Wire-up fastmap
  UBI: Add fastmap core
  UBI: Add fastmap support to the WL sub-system
  UBI: Add fastmap stuff to attach.c
  UBI: Wire-up ->fm_sem
  UBI: Add fastmap bits to build.c
  UBI: Add self_check_eba()
  UBI: Export next_sqnum()
  UBI: Add fastmap stuff to ubi.h
  UBI: Add fastmap on-flash data structures