The problem: NAND flashes have different amount of initial bad physical
eraseblocks (marked as bad by the manufacturer). For example, for 256MiB
Samsung OneNAND flash there might be from 0 to 40 bad initial eraseblocks,
which is about 2%. When UBI is used as the base system, one needs to know
the exact amount of good physical eraseblocks, because this number is
needed to create the UBI image which is put to the devices during
production. But this number is not know, which forces us to use the
minimum number of good physical eraseblocks. And UBI additionally
reserves some percentage of physical eraseblocks for bad block handling
(default is 1%), so we have 1-3% of PEBs reserved at the end, depending
on the amount of initial bad PEBs. But it is desired to always have
1% (or more, depending on the configuration).

Solution: this patch adds an "auto-resize" flag to the volume table.
The volume which has the "auto-resize" flag will automatically be re-sized
(enlarged) on the first UBI initialization. UBI clears the flag when
the volume is re-sized. Only one volume may have the "auto-resize" flag.

So, the production UBI image may have one volume with "auto-resize"
flag set, and its size is automatically adjusted on the first boot
of the device.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Save 12 bytes of RAM per volume by using bit-fields instead of integers.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/ubi/cdev.c: In function ‘vol_cdev_read’:
drivers/mtd/ubi/cdev.c:187: warning: unused variable ‘vol_id’
CC [M]  drivers/mtd/ubi/kapi.o
drivers/mtd/ubi/kapi.c: In function ‘ubi_leb_erase’:
drivers/mtd/ubi/kapi.c:483: warning: unused variable ‘vol_id’
drivers/mtd/ubi/kapi.c: In function ‘ubi_leb_unmap’:
drivers/mtd/ubi/kapi.c:544: warning: unused variable ‘vol_id’
drivers/mtd/ubi/kapi.c: In function ‘ubi_leb_map’:
drivers/mtd/ubi/kapi.c:582: warning: unused variable ‘vol_id’
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

This slab cache is not really needed since the number of objects
is low and the constructor does not make much sense because we
allocate oblects when doint I/O, which is way slower then allocation.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

If there were multiple bit errors in the data s3c2410_nand_correct_data()
was returning 0 (no error) instead of -1, so the upper layers (like JFFS2)
would not know the data is corrupt.
Signed-off-by: Matt Reimer <mreimer@vpop.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

According to "Common Flash Memory Interface Publication 100" dated December 1,
2001, the interface code for x16/x32 chips is 0x0005, and not 0x0004 used so
far.
Signed-off-by: Bartlomiej Sieka <tur@semihalf.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Some hardware, such as the enhanced local bus controller used on some
mpc83xx chips, does ecc transparently when reading and writing data, rather
than providing a generic calculate/correct mechanism that can be exported to
the nand subsystem.

The subsystem should not BUG() when calculate, correct, or hwctl are
missing, if the methods that call them have been overridden.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

posix_acl_clone does a memory allocation and sets a reference count, so
posix_acl_release is needed afterwards to free it.

The problem was fixed using the following semantic patch.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
type T;
identifier E;
expression E1, E2;
int ret;
statement S;
@@

  T E;
  <+...
(
  E = \(posix_acl_clone\|posix_acl_alloc\|posix_acl_dup\)(...);
  if (E == NULL) S
|
  if ((E = \(posix_acl_clone\|posix_acl_alloc\|posix_acl_dup\)(...)) == NULL) S
)
  ... when != E2 = E
      when strict
(
  posix_acl_release(E);
|
  E1 = E;
|
+ posix_acl_release(E);
  return;
|
+ posix_acl_release(E);
  return ret;
)
  ...+>
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

It should be done as a physmap device, and people keep turning it on and
whining about it.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

"include/linux/mtd/mtd.h" declares "mtd_oob_ops.retlen" as size_t, which
is 64 bits on targets with a 64 bit addressing. The MEMWRITEOOB ioctl
calls copy_to_user() to write it back to "mtd_oob_buf.length", which is
declared in "include/linux/mtd-abi.h" as uint32_t. Since powerpc is a
big endian architecture, this only copies the upper 32 bits of the
address, which is always 0.
Signed-off-by: David Scidmore <dscidmore@xes-inc.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

When creating a new volume, do not forget to increment the
vol_count variable.

Also, users are not interested in internal volumes, so do not show
them in the volumes_count sysfs file.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Be strict and accept only KiB, MiB and GiB, not Kib, not kib, etc.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Expose number or the underlying MTD device in sysfs.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI allows to specify MTD device name or number when the module is being
loaded. When parsing MTD device identity string, it first tries to treat
it as device NAME, and if that fails, it treats it as device number.

Make it vice-versa as this is more logical and makes less troubles when
you have an MTD device named "1" and try to load mtd1 which has different
name. This is especially easy to hit when gluebi is enabled.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Introduce a separate mutex which serializes volumes checking,
because we cammot really use volumes_mutex - it cases reverse
locking problems with mtd_tbl_mutex when gluebi is used -
thanks to lockdep.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Actually implement the MTD device attach/detach handlers.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

'data_offset' parameter does not really make sense and it is not
needed. Get rid of it.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Prepare the attach and detach functions to by used outside of
module initialization:

* detach function checks reference count before detaching
* it kills the background thread as well
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

This is one more step on the way to "removable" UBI devices. It
adds reference counting for UBI devices. Every time a volume on
this device is opened - the device's refcount is increased. It
is also increased if someone is reading any sysfs file of this
UBI device or of one of its volumes.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch is a preparation to make UBI devices dynamic. It
adds an UBI control device which has dynamically allocated
major number and registers itself as "ubi_ctrl". It does not
do anything so far. The idea is that this device will allow
to attach/detach MTD devices from userspace.

This is symilar to what the Linux device mapper has.

The next things to do are:
* Fix UBI, because it now assumes UBI devices cannot go away
* Implement control device ioctls which will attach/detach MTD
  devices
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

The flush function should finish all the pending jobs. But if
somebody else is doing a work, this function should wait and let
it finish.

This patche uses rw semaphore for synchronization purpose - it
just looks quite convinient.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Add proper log level to printk's.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

When the WL worker is moving an LEB, the volume might go away
occasionally. UBI does not handle these situations correctly.

This patch introduces a new mutex which serializes wear-levelling
worker and the the 'ubi_wl_put_peb()' function. Now, if one puts
an LEB, and its PEB is being moved, it will wait on the mutex.
And because we unmap all LEBs when removing volumes, this will make
the volume remove function to wait while the LEB movement
finishes.

Below is an example of an oops which should be fixed by this patch:

Pid: 9167, comm: io_paral Not tainted (2.6.24-rc5-ubi-2.6.git #2)
EIP: 0060:[<f884a379>] EFLAGS: 00010246 CPU: 0
EIP is at prot_tree_del+0x2a/0x63 [ubi]
EAX: f39a90e0 EBX: 00000000 ECX: 00000000 EDX: 00000134
ESI: f39a90e0 EDI: f39a90e0 EBP: f2d55ddc ESP: f2d55dd4
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process io_paral (pid: 9167, ti=f2d54000 task=f72a8030 task.ti=f2d54000)
Stack: f39a95f8 ef6aae50 f2d55e08 f884a511 f88538e1 f884ecea 00000134 00000000
       f39a9604 f39a95f0 efea8280 00000000 f39a90e0 f2d55e40 f8847261 f8850c3c
       f884eaad 00000001 000000b9 00000134 00000172 000000b9 00000134 00000001
Call Trace:
 [<c0105227>] show_trace_log_lvl+0x1a/0x30
 [<c01052e2>] show_stack_log_lvl+0xa5/0xca
 [<c01053d6>] show_registers+0xcf/0x21b
 [<c0105648>] die+0x126/0x224
 [<c0119a62>] do_page_fault+0x27f/0x60d
 [<c037dd62>] error_code+0x72/0x78
 [<f884a511>] ubi_wl_put_peb+0xf0/0x191 [ubi]
 [<f8847261>] ubi_eba_unmap_leb+0xaf/0xcc [ubi]
 [<f8843c21>] ubi_remove_volume+0x102/0x1e8 [ubi]
 [<f8846077>] ubi_cdev_ioctl+0x22a/0x383 [ubi]
 [<c017d768>] do_ioctl+0x68/0x71
 [<c017d7c6>] vfs_ioctl+0x55/0x271
 [<c017da15>] sys_ioctl+0x33/0x52
 [<c0104152>] sysenter_past_esp+0x5f/0xa5
 =======================
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Explain better the purpose of thie 'move_to_put' stuff.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Also, use single dbg_msg() macro for all prints.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Make the code more consistent by requiring the caller to lock the
ubi->volume_mutex, because this is what we do for updates.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Add ref_count field to UBI volumes and remove weired "vol->removed"
field. This way things are better understandable and we do not have
to do whold show_attr operation under spinlock.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

If we fail halfway through sysfs file creation, we may just call
sysfs remove function and it will delete all the files we created.
For non-existing files it will also be OK - the remove functions
just return -ENOENT.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch fixes error codes of the functions - if the device number
is out of range, -EINVAL should be returned. It also removes unneeded
try_module_get call from the open by name function.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Error path in volume creation is bogus. First of, it ovverrides the
'err' variable and returns zero to the caller. Second, ubi_assert()
in the release function is wrong.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

When a volume is opened, get its kref via get_device() call.
And put the reference when closing the volume. With this, we
may have a bit saner volume delete.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Transform vtbl_mutex to volumes_mutex - this just makes code
easier to understand.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Pass volume description object to the EBA function which makes
more sense, and EBA function do not have to find the volume
description object by volume ID.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

E.g., it oopsed in case of: modprobe ubi mtd = 0
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

This global variablea is not really needed, remove it
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Similarly to ltree_entry_slab, it makes more sense to create
and destroy ubi_wl_entry slab on module initialization/exit.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Since the ltree_entry slab cache is a global entity, which is
used by all UBI devices, it is more logical to create it on
module initialization time and destro on module exit time.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>