When the UBI device is nearly full, i.e. all LEBs are mapped, we have
only one spare LEB left - the one we reserved for WL purposes. Well,
I do not count the LEBs which were reserved for bad PEB handling -
suppose NOR flash for simplicity. If an "atomic LEB change operation"
is run, and the WL unit is moving a LEB, we have no spare LEBs to
finish the operation and fail, which is not good. Moreover, if there
are 2 or more simultanious "atomic LEB change" requests, only one of
them has chances to succeed, the other will fail with -ENOSPC. Not
good either.

This patch does 2 things:
1. Reserves one PEB for the "atomic LEB change" operation.
2. Serealize the operations so that only on of them may run
   at a time (by means of a mutex).
Pointed-to-by: NBrijesh Singh <brijesh.s.singh@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

More handy since word hexdump prints in host endian.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Similar reason as in case of the previous patch: it causes
deadlocks if a filesystem with writeback support works on top
of UBI. So pre-allocate needed buffers when attaching MTD device.
We also need mutexes to protect the buffers, but they do not
cause much contantion because they are used in recovery, torture,
and WL copy routines, which are called seldom.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Use GFP_NOFS flag when allocating memory on I/O path, because otherwise
we may deadlock the filesystem which works on top of us. We observed
the deadlocks with UBIFS. Example:

VFS->FS lock a lock->UBI->kmalloc()->VFS writeback->FS locks the same
lock again.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

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

I can't find anything guaranteeing that 'ubi_num' cannot be <0 in
drivers/mtd/ubi/kapi.c::ubi_open_volume(), and in fact the code
even tests for that and errors out if so. Unfortunately the test
for "ubi_num < 0" happens after we've already used 'ubi_num' as
an array index - bad thing to do if it is negative.
This patch moves the test earlier in the function and then moves
the indexing using that variable after the check. A bit safer :-)
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

I hit those situations and found out lack of print messages. Add more prints
when erase problems occur.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Fix "symbol shadows an earlier one" warnings. Although they are harmless
but it does not hurt to fix them and make sparse happy.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Coverity (1769) found the following problem: if the erase counter
overflow check triggers, ec_hdr is leaked.

Moving the allocation after the overflow check should take care of it.
Signed-off-by: NFlorin Malita <fmalita@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Slab destructors were no longer supported after Christoph's
c59def9f change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

cdev.c whines in current git:

drivers/mtd/ubi/cdev.c: In function `major_to_device':
drivers/mtd/ubi/cdev.c:67: warning: control reaches end of non-void function

Shut it up.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Do not switch to read-only mode in case of -EINTR and some
other obvious cases. Switch to RO mode only when we do not
know what is the error.
Reported-by: NVinit Agnihotri <vinit.agnihotri@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

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

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

The use of try_module_get(THIS_MODULE) in ubi_get_device_info does not
offer real protection against unexpected driver unloads, since we could
be preempted before try_modules_get gets executed. It is the caller who
should manipulate the refcounts. Besides, ubi_get_device_info is an
exported symbol which guarantees protection when accessed through
symbol_get.
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

I was experiencing overflows in multiplications for
volume->used_bytes in vmt.c & vtbl.c, while creating & resizing large volumes.

vol->used_bytes is long long however its 2 operands vol->used_ebs &
vol->usable_leb_size
are int. So their multiplication for larger values causes integer overflows.
Typecasting them solves the problem.

My machine & flash details:

64Bit dual-core AMD opteron, 1 GB RAM, linux 2.6.18.3.
mtd size = 6GB, volume size= 5GB, peb_size = 4MB.

heres patch which does the fix.
Signed-off-by: NVinit Agnihotri <vinit.agnihotri@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Do not zero max_sqnum after a new volume has been found.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Hi,I came across problem of having two leb with same sequence no.This
happens when we continuously write one block again and again and reboot
machine before background thread erases those blocks.
The problem here was,when we find two blocks with same sequence no,we take
the higher one,but we were not updating max seq no,so next block may have
the same seqnum.
This patch solves this problem.
Signed-off-by: NBrijesh Singh <brijesh.s.singh@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

There is signed multiplication assigned to unsigned ei.addr in io.c.
This causes wrong addresses for big multiplication.This patch solves the
problem.
Signed-off-by: NBrijesh Singh <brijesh.s.singh@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

atomic_leb_change() is only allowed for dynamic volumes, so set
the volume type correctly.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Increase UBI devices couter after the message, not before.
Signed-off-by: NVinit Agnihotri <vinit.agnihotri@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Do not check volumes which are currently in use because thay may be
in inconsistent state.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When volume creation fails, we have to set ubi->volumes[vol_id]
back to NULL.

This patch also tweaks some debugging stuff.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2
Signed-off-by: NVignesh Babu <vignesh.babu@wipro.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

ubi->vtbl is allocated using vmalloc() in vtbl.c empty_create_lvol(),
but it is freed in build.c with kfree()
Signed-off-by: NVinit Agnihotri <vinit.agnihotri@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Do not call 'ubi_wl_put_peb()' if the LEB was unmapped.
Reported-by: NGabor Loki <loki@inf.u-szeged.hu>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Kill UBI's homegrown endianess handling and replace it with
the standard kernel endianess handling.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

- don't do access_ok + get/put user but use the proper macro
- remove useless checks
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

No need to unlock the lock, this will be done at out_unlock.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Use coma at the the last elements of structure initializer.

Daniel Stone's explanation:

Because it turns:
-   .attr   = foo
+   .attr   = foo,
+   .bar    = baz

into:
+   .bar    = baz,

i.e., far less likely to screw up a merge.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI allocates temporary buffers of PEB size, which may be 256KiB.
Use vmalloc instead of kmalloc for such big temporary buffers.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Add few comments above ubi_scan_add_used() to explain why it is so
complex. Requested by Satyam Sharma <satyam.sharma@gmail.com>.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

In case of static volumes, make emulated MTD device size to
be equivalent to data size, rather then volume size.
Reported-by: NJohn Smith <john@arrows.demon.co.uk>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

In case of static volumes it is prohibited to read more data
then available.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

There were several bugs in volume table creation error path. Thanks to
Satyam Sharma <satyam.sharma@gmail.com> and Florin Malita <fmalita@gmail.com>
for finding and analysing them: http://lkml.org/lkml/2007/5/3/274

This patch makes ubi_scan_add_to_list() static and renames it to
add_to_list(), just because it is not needed outside scan.c anymore.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Coverity (CID 1614) spotted new_seb being dereferenced after kfree() in
create_vtbl's write_error path.
Signed-off-by: NFlorin Malita <fmalita@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Reported-by: NEric Sesterhenn / Snakebyte <snakebyte@gmx.de>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Mark variables in drivers/* with uninitialized_var() if such a warning
appears, and analysis proves that the var is initialized properly on all
paths it is used.
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Signed-off-by: NJeff Garzik <jeff@garzik.org>

Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves.  This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie.  to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear.  Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NNigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>