Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "The rest of MM and the rest of everything else: hotfixes, ipc, misc,
  procfs, lib, cleanups, arm"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (67 commits)
  ARM: dma-api: fix max_pfn off-by-one error in __dma_supported()
  treewide: remove redundant IS_ERR() before error code check
  include/linux/cpumask.h: don't calculate length of the input string
  lib: new testcases for bitmap_parse{_user}
  lib: rework bitmap_parse()
  lib: make bitmap_parse_user a wrapper on bitmap_parse
  lib: add test for bitmap_parse()
  bitops: more BITS_TO_* macros
  lib/string: add strnchrnul()
  proc: convert everything to "struct proc_ops"
  proc: decouple proc from VFS with "struct proc_ops"
  asm-generic/tlb: provide MMU_GATHER_TABLE_FREE
  asm-generic/tlb: rename HAVE_MMU_GATHER_NO_GATHER
  asm-generic/tlb: rename HAVE_MMU_GATHER_PAGE_SIZE
  asm-generic/tlb: rename HAVE_RCU_TABLE_FREE
  asm-generic/tlb: add missing CONFIG symbol
  asm-gemeric/tlb: remove stray function declarations
  asm-generic/tlb: avoid potential double flush
  mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush
  powerpc/mmu_gather: enable RCU_TABLE_FREE even for !SMP case
  ...

1 files changed, 10 insertions, 6 deletions

diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index ec3b5865c1be..7146da061693 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -1868,12 +1868,16 @@ There are some more advanced barrier functions:
  (*) smp_mb__before_atomic();
  (*) smp_mb__after_atomic();
 
-     These are for use with atomic (such as add, subtract, increment and
-     decrement) functions that don't return a value, especially when used for
-     reference counting.  These functions do not imply memory barriers.
-
-     These are also used for atomic bitop functions that do not return a
-     value (such as set_bit and clear_bit).
+     These are for use with atomic RMW functions that do not imply memory
+     barriers, but where the code needs a memory barrier. Examples for atomic
+     RMW functions that do not imply are memory barrier are e.g. add,
+     subtract, (failed) conditional operations, _relaxed functions,
+     but not atomic_read or atomic_set. A common example where a memory
+     barrier may be required is when atomic ops are used for reference
+     counting.
+
+     These are also used for atomic RMW bitop functions that do not imply a
+     memory barrier (such as set_bit and clear_bit).
 
      As an example, consider a piece of code that marks an object as being dead
      and then decrements the object's reference count: