mm, vmalloc: iterate vmap_area_list, instead of vmlist in vread/vwrite()
mm, vmalloc: iterate vmap_area_list, instead of vmlist in vread/vwrite()

Now, when we hold a vmap_area_lock, va->vm can't be discarded.  So we can
safely access to va->vm when iterating a vmap_area_list with holding a
vmap_area_lock.  With this property, change iterating vmlist codes in
vread/vwrite() to iterating vmap_area_list.

There is a little difference relate to lock, because vmlist_lock is mutex,
but, vmap_area_lock is spin_lock.  It may introduce a spinning overhead
during vread/vwrite() is executing.  But, these are debug-oriented
functions, so this overhead is not real problem for common case.

Signed-off-by: Joonsoo Kim <d91a346a9a76eb1627d34d097d6cb4c8e5067100@gmail.com>
Signed-off-by: Joonsoo Kim <bb6c8cfe7699e0f11d1bee88022eb563a5f8e881@lge.com>
Cc: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
Cc: "H. Peter Anvin" <8a453bad9912ffe59bc0f0b8abe03df9be19379e@zytor.com>
Cc: Atsushi Kumagai <39d7451d585f773af30891a53feb06e85def8e7d@mxc.nes.nec.co.jp>
Cc: Chris Metcalf <074881f6f5da4d3b5278870ff234d1077ee622c0@tilera.com>
Cc: Dave Anderson <52db9057163f2b831a5452d895239a249597d1cc@redhat.com>
Cc: Eric Biederman <8a741aa8cbd77ebc4a56ddb528ce9fd15d42f034@xmission.com>
Cc: Guan Xuetao <e3695cf74a76bd4528efcb62d7670a686738ecc1@mprc.pku.edu.cn>
Cc: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@kernel.org>
Cc: Vivek Goyal <61d11262d0d9873ddb5a887f48fcb04e8c5973d0@redhat.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs