lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table()

We are seeing a lot of sg_alloc_table allocation failures using the new
drm prime infrastructure.  We isolated the cause to code in
__sg_alloc_table that was re-writing the gfp_flags.

There is a comment in the code that suggest that there is an assumption
about the allocation coming from a memory pool.  This was likely true
when sg lists were primarily used for disk I/O.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <rob.clark@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
switch the protection of percpu_counter list to spinlock

... making percpu_counter_destroy() non-blocking

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
lib/vsprintf.c: "%#o",0 becomes '0' instead of '00'

number()'s behaviour is slighly changed: 0 becomes "0" instead of "00"
when using the flag SPECIAL and base 8.

Before:
Number\Format  %o    %#o  %x    %#x
            0     0   00    0   0x0
            1     1   01    1   0x1
           16    20  020   10  0x10

After:
Number\Format  %o    %#o  %x    %#x
            0     0    0    0   0x0
            1     1   01    1   0x1
           16    20  020   10  0x10

Signed-off-by: Pierre Carrier <pierre@spotify.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vsprintf: further optimize decimal conversion

Previous code was using optimizations which were developed to work well
even on narrow-word CPUs (by today's standards).  But Linux runs only on
32-bit and wider CPUs.  We can use that.

First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly
divide by 10 much larger numbers, and thus we can print groups of 9 digits
instead of groups of 5 digits.

Next: there are two algorithms to print larger numbers.  One is generic:
divide by 1000000000 and repeatedly print groups of (up to) 9 digits.
It's conceptually simple, but requires an (unsigned long long) /
1000000000 division.

Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
manipulates them cleverly and generates groups of 4 decimal digits.  It so
happens that it does NOT require long long division.

If long is > 32 bits, division of 64-bit values is relatively easy, and we
will use the first algorithm.  If long long is > 64 bits (strange
architecture with VERY large long long), second algorithm can't be used,
and we again use the first one.

Else (if long is 32 bits and long long is 64 bits) we use second one.

And third: there is a simple optimization which takes fast path not only
for zero as was done before, but for all one-digit numbers.

In all tested cases new code is faster than old one, in many cases by 30%,
in few cases by more than 50% (for example, on x86-32, conversion of
12345678).  Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit
case.

This patch is based upon an original from Michal Nazarewicz.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Douglas W Jones <jones@cs.uiowa.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Conflicts:
	lib/vsprintf.c
vsprintf: add %pMR for Bluetooth MAC address

Bluetooth uses mostly LE byte order which is reversed for visual
interpretation.  Currently in Bluetooth in use unsafe batostr function.

This is a slightly modified version of Joe's patch (sent Sat, Dec 4,
2010).

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Conflicts:
	lib/vsprintf.c
vsprintf: add support of '%*ph[CDN]'

There are many places in the kernel where the drivers print small buffers
as a hex string.  This patch adds a support of the variable width buffer
to print it as a hex string with a delimiter.  The idea came from Pavel
Roskin here: http://www.digipedia.pl/usenet/thread/18835/17449/

Sample output of
	pr_info("buf[%d:%d] %*phC\n", from, len, len, &buf[from]);
could be look like this:
	[ 0.726130] buf[51:8] e8:16:b6:ef:e3:74:45:6e
	[ 0.750736] buf[59:15] 31:81:b8:3f:35:49:06:ae:df:32:06:05:4a:af:55
	[ 0.757602] buf[17:5] ac:16:d5:2c:ef

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Conflicts:
	lib/vsprintf.c
lib: vsprintf: optimize division by 10 for small integers

Shrink the reciprocal approximations used in put_dec_full4() based on the
comments in put_dec_full9().

Signed-off-by: George Spelvin <linux@horizon.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib: vsprintf: optimize division by 10000

The same multiply-by-inverse technique can be used to convert division by
10000 to a 32x32->64-bit multiply.

Signed-off-by: George Spelvin <linux@horizon.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib: vsprintf: optimize put_dec_trunc8()

If you're going to have a conditional branch after each 32x32->64-bit
multiply, might as well shrink the code and make it a loop.

This also avoids using the long multiply for small integers.

(This leaves the comments in a confusing state, but that's a separate
patch to make review easier.)

Signed-off-by: George Spelvin <linux@horizon.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Rabin Vincent <rabin@rab.in>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib: vsprintf: fix broken comments

Numbering the 8 potential digits 2 though 9 never did make a lot of sense.

Signed-off-by: George Spelvin <linux@horizon.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/vsprintf: update documentation to cover all of %p[Mm][FR]

Acked-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
scatterlist: add sg_alloc_table_from_pages function

This patch adds a new constructor for an sg table. The table is constructed
from an array of struct pages. All contiguous chunks of the pages are merged
into a single sg nodes. A user may provide an offset and a size of a buffer if
the buffer is not page-aligned.

The function is dedicated for DMABUF exporters which often perform conversion
from an page array to a scatterlist. Moreover the scatterlist should be
squashed in order to save memory and to speed-up the process of DMA mapping
using dma_map_sg.

The code is based on the patch 'v4l: vb2-dma-contig: add support for
scatterlist in userptr mode' and hints from Laurent Pinchart.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Andrew Morton <akpm@linux-foundation.org>
scatterlist: atomic sg_mapping_iter() no longer needs disabled IRQs

SG mapping iterator w/ SG_MITER_ATOMIC set required IRQ disabled because
it originally used KM_BIO_SRC_IRQ to allow use from IRQ handlers.
kmap_atomic() has long been updated to handle stacking atomic mapping
requests on per-cpu basis and only requires not sleeping while mapped.

Update sg_mapping_iter such that atomic iterators only require disabling
preemption instead of disabling IRQ.

While at it, convert wte weird @ARG@ notations to @ARG in the comment of
sg_miter_start().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
workqueue: change BUG_ON() to WARN_ON()

This BUG_ON() can be triggered if you call schedule_work() before
calling INIT_WORK().  It is a bug definitely, but it's nicer to just
print a stack trace and return.

Reported-by: Matt Renzelmann <mjr@cs.wisc.edu>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
workqueue: Catch more locking problems with flush_work()

If a workqueue is flushed with flush_work() lockdep checking can
be circumvented. For example:

 static DEFINE_MUTEX(mutex);

 static void my_work(struct work_struct *w)
 {
         mutex_lock(&mutex);
         mutex_unlock(&mutex);
 }

 static DECLARE_WORK(work, my_work);

 static int __init start_test_module(void)
 {
         schedule_work(&work);
         return 0;
 }
 module_init(start_test_module);

 static void __exit stop_test_module(void)
 {
         mutex_lock(&mutex);
         flush_work(&work);
         mutex_unlock(&mutex);
 }
 module_exit(stop_test_module);

would not always print a warning when flush_work() was called.
In this trivial example nothing could go wrong since we are
guaranteed module_init() and module_exit() don't run concurrently,
but if the work item is schedule asynchronously we could have a
scenario where the work item is running just at the time flush_work()
is called resulting in a classic ABBA locking problem.

Add a lockdep hint by acquiring and releasing the work item
lockdep_map in flush_work() so that we always catch this
potential deadlock scenario.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
random: fix up sparse warnings

Add extern and static declarations to suppress sparse warnings

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
PM: Introduce suspend state PM_SUSPEND_FREEZE

PM_SUSPEND_FREEZE state is a general state that
does not need any platform specific support, it equals
frozen processes + suspended devices + idle processors.

Compared with PM_SUSPEND_MEMORY,
PM_SUSPEND_FREEZE saves less power
because the system is still in a running state.
PM_SUSPEND_FREEZE has less resume latency because it does not
touch BIOS, and the processors are in idle state.

Compared with RTPM/idle,
PM_SUSPEND_FREEZE saves more power as
1. the processor has longer sleep time because processes are frozen.
   The deeper c-state the processor supports, more power saving we can get.
2. PM_SUSPEND_FREEZE uses system suspend code path, thus we can get
   more power saving from the devices that does not have good RTPM support.

This state is useful for
1) platforms that do not have STR, or have a broken STR.
2) platforms that have an extremely low power idle state,
   which can be used to replace STR.

The following describes how PM_SUSPEND_FREEZE state works.
1. echo freeze > /sys/power/state
2. the processes are frozen.
3. all the devices are suspended.
4. all the processors are blocked by a wait queue
5. all the processors idles and enters (Deep) c-state.
6. an interrupt fires.
7. a processor is woken up and handles the irq.
8. if it is a general event,
   a) the irq handler runs and quites.
   b) goto step 4.
9. if it is a real wake event, say, power button pressing, keyboard touch, mouse moving,
   a) the irq handler runs and activate the wakeup source
   b) wakeup_source_activate() notifies the wait queue.
   c) system starts resuming from PM_SUSPEND_FREEZE
10. all the devices are resumed.
11. all the processes are unfrozen.
12. system is back to working.
Known Issue:
The wakeup of this new PM_SUSPEND_FREEZE state may behave differently
from the previous suspend state.
Take ACPI platform for example, there are some GPEs that only enabled
when the system is in sleep state, to wake the system backk from S3/S4.
But we are not touching these GPEs during transition to PM_SUSPEND_FREEZE.
This means we may lose some wake event.
But on the other hand, as we do not disable all the Interrupts during
PM_SUSPEND_FREEZE, we may get some extra "wakeup" Interrupts, that are
not available for S3/S4.

The patches has been tested on an old Sony laptop, and here are the results:

Average Power:
1. RPTM/idle for half an hour:
   14.8W, 12.6W, 14.1W, 12.5W, 14.4W, 13.2W, 12.9W
2. Freeze for half an hour:
   11W, 10.4W, 9.4W, 11.3W 10.5W
3. RTPM/idle for three hours:
   11.6W
4. Freeze for three hours:
   10W
5. Suspend to Memory:
   0.5~0.9W

Average Resume Latency:
1. RTPM/idle with a black screen: (From pressing keyboard to screen back)
   Less than 0.2s
2. Freeze: (From pressing power button to screen back)
   2.50s
3. Suspend to Memory: (From pressing power button to screen back)
   4.33s

From the results, we can see that all the platforms should benefit from
this patch, even if it does not have Low Power S0.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
modified for Mako from LKML reference

Signed-off-by: Paul Reioux <reioux@gmail.com>
fat: eliminate iterations in fat_search_long and __fat_readdir in case of EOD

When doing lookups via fat_search_long(), we can stop checking for
further entries if we detect End of Directory, i.e. if (de->name[0] ==
0x00).The current code traverses the cluster chain of a directory until a hit
is found or till the last cluster for that directory, ignoring the EOD
mark. Fix this.
Likewise,when readdir(3) is called, we can stop checking for further
entries in __fat_readdir() when we hit EOD.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ravishankar N <ravi.n1@samsung.com>
tmpfs: fix mempolicy object leaks

This patch fixes several mempolicy leaks in the tmpfs mount logic.
These leaks are slow - on the order of one object leaked per mount
attempt.

Leak 1 (umount doesn't free mpol allocated in mount):
    while true; do
        mount -t tmpfs -o mpol=interleave,size=100M nodev /mnt
        umount /mnt
    done

Leak 2 (errors parsing remount options will leak mpol):
    mount -t tmpfs -o size=100M nodev /mnt
    while true; do
        mount -o remount,mpol=interleave,size=x /mnt 2> /dev/null
    done
    umount /mnt

Leak 3 (multiple mpol per mount leak mpol):
    while true; do
        mount -t tmpfs -o mpol=interleave,mpol=interleave,size=100M nodev /mnt
        umount /mnt
    done

This patch fixes all of the above.  I could have broken the patch into
three pieces but is seemed easier to review as one.

Signed-off-by: Greg Thelen <gthelen@google.com>
modified for Mako kernel from LKML reference

Signed-off-by: faux123 <reioux@gmail.com>
SCHEDULER: Autogroup patch group by current user android UID instead of task ID