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

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: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

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

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

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

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

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

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

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

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

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

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

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

Always print error code with error messages, sometimes it is
extremely helpful info.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Remove redundant ubi->major field - we have it in ubi->cdev.dev
already.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

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

This patch silences the following warning :

  drivers/mtd/ubi/vmt.c:73: warning: 'ret' may be used uninitialized in this function

gcc can't see that we always initialize ret in all situations where it is
actually used. The one case where it's not initialized is when we BUG(),
but gcc doesn't know that we won't then continue and use an uninitialized
'ret'.

This patch results in code that does exactely the same as before, but it
also makes gcc shut up, so we generate one less line of warning noise.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The idea of this interface belongs to Adrian Hunter. The
interface is extremely useful when one has to have a guarantee
that an LEB will contain all 0xFFs even in case of an unclean
reboot. UBI does have an 'ubi_leb_erase()' call which may do
this, but it is stupid and ineffecient, because it flushes whole
queue. I should be re-worked to just be a pair of unmap,
map calls.

The user of the interfaci is UBIFS at the moment.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

First allocate the necessary eraseblocks, then the optional ones.
Otherwise it allocates all PEBs for bad EB handling, and fails
on then following EBA LEB allocation.
Reported-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When NAND detects an ECC error, it returns -EBADMSG. It does not
stop reading requested data if one page has an ECC error, it keeps
going and reads all the requested data. If it fails to read all
the data, it does not return -EBADMSG, but returns the error code
which reflects the reason of the failure.

But some drivers may have bugs (e.g., OneNAND had) and stop reading
after the first ECC error, so it returns -EBADMSG. In turn, UBI
propagates this up to the caller. The caller will treat this as
"all the requested data was read, but there was an ECC error".

So we change the error code to -EIO if it is -EBADMSG and the read
length is less then the requested length. We also add an assertion,
so if UBI debugging is enabled, UBI will bug.
Pointed-to-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.

The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.

[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>