drivers/staging/android: backport ashmem from hammerhead

backport & squash by boype

ashmem: Anonymous shared memory subsystem

The anonymous shared memory (ashmem) subsystem provides a
Unix-y,file-based shared memory interface to user-space. It
works like anonymous memory (e.g. mmapping fd=0) except if
you share the file descriptor via the usual means, you will
share the mapping. The shared memory can be accessed via both
mmap or file I/O. The backing store is a simple shmem file.

Additionally, ashmem introduces the concept of page pinning.
Pinned pages (the default) behave like any anonymous memory.
Unpinned pages are available to the kernel for eviction during
VM pressure. When repinning the pages, the return value
instructs user-space as to any eviction. In this manner,
user-space processes may implement caching and similar
resource management that efficiently integrates with kernel
memory management.

Signed-off-by: Robert Love <rlove@google.com>

ashmem: Don't install fault handler for private mmaps.

Ashmem is used to create named private heaps. If this heap is backed
by a tmpfs file it will allocate two pages for every page touched.
In 2.6.27, the extra page would later be freed, but 2.6.29 does not
scan anonymous pages when running without swap so the memory is not
freed while the file is referenced. This change changes the behavior
of private ashmem mmaps to match /dev/zero instead tmpfs.

Signed-off-by: Arve Hjønnevåg <arve@android.com>

ashmem: Add common prefix to name reported in /proc/pid/maps

Signed-off-by: Arve Hjønnevåg <arve@android.com>

ashmem: don't require a page aligned size

This makes ashmem more similar to shmem and mmap, by
not requiring the specified size to be page aligned,
instead rounding it internally as needed.

Signed-off-by: Marco Nelissen <marcone@android.com>
[jstultz: Improved commit subject and included patch description
from rlove. Also moved ashmem files to staging dir, and reworked
code to avoid touching mm/shmem.c while we're in staging.]
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

ashmem: Implement read(2) in ashmem driver

Signed-off-by: Bjorn Bringert <bringert@android.com>
[jstultz: Tweaked commit subject]
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

ashmem: Fix ASHMEM_SET_PROT_MASK.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

ashmem: Update arguments of shrinker for 2.6.35

Signed-off-by: Colin Cross <ccross@google.com>
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

ashmem: Support lseek(2) in ashmem driver

Signed-off-by: Bjorn Bringert <bringert@android.com>
[jstultz: tweaked commit subject]
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

ashmem: Fix arguments to ashmem_shrink

The arguments to shrink functions have changed, update
ashmem_shrink to match.

Signed-off-by: Colin Cross <ccross@android.com>
[jstultz: tweaked commit subject]
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

ashmem: Whitespace cleanups

Fixes checkpatch warnings with the ashmem.c file

CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/android/ashmem.c: Cleanups

Minor cleanups that consist of removal of a whitespace and
make file_operations const.

Signed-off-by: Tracey Dent <tdent48227@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ashmem: Add shmem_set_file to mm/shmem.c

NOT FOR STAGING
This patch re-adds the original shmem_set_file to mm/shmem.c
and converts ashmem.c back to using it.

CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
CC: Greg KH <greg@kroah.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>

ashmem: Move ashmem.h from staging to include/linux and export it

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

ashmem: Add routines to get in kernel reference to ashmem file

Add get_ashmem_file and put_ashmem_file routines in ashmem driver to get
and return file references to ashmem file from within the kernel.

Change-Id: Ifbb54f7c1aab90f6d656a10a3c40ca2b65ceb89a
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>

staging: ashmem: Fix the build failure when OUTER_CACHE is enabled

ashmem driver is failing to build when OUTER_CACHE is enabled
through the CACHE_L2X0 option. Fix it with appropriate new
offset routines.

Change-Id: I298f9bb32899f20e17407b5210d0859d6308c035
Signed-off-by: Trilok Soni <tsoni@codeaurora.org>

drivers: staging: android: Fix ashmem vm range comparison to stop roll-over

Every time ASHMEM_CACHE_INV_RANGE was sent to an IOCTL a roll-over was
occurring, causing the check to fail. This was comparing a start + size
range with a start + end range, and if the start + end was less than the
start + size the ioctl would fail. The end value was always equal to
start + size from all tests I ran, and since the roll-over occurred with
start + end, it was always less than start. Setting the check to compare
start + size > end fixes this.

Change-Id: I3e4356ab40d8c745fd91eb0cc6b1aaed73494140
Signed-off-by: Matthew Trusten <mtrusten@codeaurora.org>

ashmem: avoid deadlock between read and mmap calls

Avoid holding ashmem_mutex across code that can page fault.  Page faults
grab the mmap_sem for the process, which are also held by mmap calls
prior to calling ashmem_mmap, which locks ashmem_mutex.  The reversed
order of locking between the two can deadlock.

The calls that can page fault are read() and the ASHMEM_SET_NAME and
ASHMEM_GET_NAME ioctls.  Move the code that accesses userspace pages
outside the ashmem_mutex.

Bug: 9261835
Change-Id: If1322e981d29c889a56cdc9dfcbc6df2729a45e9
Signed-off-by: Todd Poynor <toddpoynor@google.com>

Conflicts:
	drivers/staging/android/Kconfig
	drivers/staging/android/ashmem.c
	include/linux/ashmem.h
drivers/staging/android: backport binder from hammerhead
All commits up to:
	Staging: android: binder: Fix memory leak on thread/process exit

backport & squash by boype

Staging: android: binder: Don't call dump_stack in binder_vma_open

If user-space partially unmaps the driver, binder_vma_open
would dump the kernel stack. This is not a kernel bug however
and will be treated as if the whole area was unmapped once
binder_vma_close gets called.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Staging: android: binder: Fix crashes when sharing a binder file between processes

Opening the binder driver and sharing the file returned with
other processes (e.g. by calling fork) can crash the kernel.
Prevent these crashes with the following changes:
- Add a mutex to protect against two processes mmapping the
  same binder_proc.
- After locking mmap_sem, check that the vma we want to access
  (still) points to the same mm_struct.
- Use proc->tsk instead of current to get the files struct since
  this is where we get the rlimit from.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Wrap accesses to the fd_sets in struct fdtable

Wrap accesses to the fd_sets in struct fdtable (for recording open files and
close-on-exec flags) so that we can move away from using fd_sets since we
abuse the fd_set structs by not allocating the full-sized structure under
normal circumstances and by non-core code looking at the internals of the
fd_sets.

The first abuse means that use of FD_ZERO() on these fd_sets is not permitted,
since that cannot be told about their abnormal lengths.

This introduces six wrapper functions for setting, clearing and testing
close-on-exec flags and fd-is-open flags:

	void __set_close_on_exec(int fd, struct fdtable *fdt);
	void __clear_close_on_exec(int fd, struct fdtable *fdt);
	bool close_on_exec(int fd, const struct fdtable *fdt);
	void __set_open_fd(int fd, struct fdtable *fdt);
	void __clear_open_fd(int fd, struct fdtable *fdt);
	bool fd_is_open(int fd, const struct fdtable *fdt);

Note that I've prepended '__' to the names of the set/clear functions because
they require the caller to hold a lock to use them.

Note also that I haven't added wrappers for looking behind the scenes at the
the array.  Possibly that should exist too.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>

fs: Remove missed ->fds_bits from cessation use of fd_set structs internally

Stephen Rothwell reported that the following commit broke the
linux-next build:

  1fd36adcd98c: Replace the fd_sets in struct fdtable with an array of unsigned longs

Fix places where ->fds_bits needed to be removed as the core
kernel no longer uses fd_set internally for file descriptor
table management.  There are two places:

 (1) drivers/staging/android/binder.c

 (2) arch/mips/kernel/kspd.c

     Question: Should sp_cleanup() in the MIPS arch be using find_next_bit()
     or fls()?

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Ralf Bächle <ralf@linux-mips.org>
cc: Arve Hjønnevåg <arve@android.com>
Link: http://lkml.kernel.org/r/20120224105707.32170.11550.stgit@warthog.procyon.org.uk
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Staging:android: Change type for binder_debug_no_lock switch to bool

GCC warns that module_param_named() indirectly returns a bool type value
which is different from 'int' type binder_debug_no_lock declared. Change
it to bool because it is a internal switch for debugging.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: android: binder: Fix use-after-free bug

binder_update_page_range could read freed memory if the vma of the
selected process was freed right before the check that the vma
belongs to the mm struct it just locked.

If the vm_mm pointer in that freed vma struct had also been rewritten
with a value that matched the locked mm struct, then the code would
proceed and possibly modify the freed vma.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

binder: Quiet binder

The majority of the binder messages are not very informative
and useful to the reader. Make them available via debug
mechanisms.

Change-Id: Ie0d262372d10fd82b0743dfd79ce7d1de14ae143
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Staging: android: binder: Fix memory leak on thread/process exit

If a thread or process exited while a reply, one-way transaction or
death notification was pending, the struct holding the pending work
was leaked.

CRs-Fixed: 477612
Change-Id: I8b7a4f77689731a47c9e2f2fffefcac95c412e00
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 675d66b0ed5fd170d6a44cf8dbb3fa56a5347bdb
Git-repo: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>

Change-Id: Ic4458ae90447f6caa895cc62f08e515caa7790ba
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Conflicts:
	drivers/staging/android/binder.c