mm: fix NR_SECTION_ROOTS == 0 when using using sparsemem extreme.
mm: fix NR_SECTION_ROOTS == 0 when using using sparsemem extreme.

Got this while compiling for ARM/SA1100:

mm/sparse.c: In function '__section_nr':
mm/sparse.c:135: warning: 'root' is used uninitialized in this function

This patch follows Russell King's suggestion for a new calculation for
NR_SECTION_ROOTS.  Thanks also to Sergei Shtylyov for pointing out the
existence of the macro DIV_ROUND_UP.

Atsushi Nemoto observed:
: This fix doesn't just silence the warning - it fixes a real problem.
:
: Without this fix, mem_section[] might have 0 size so mem_section[0]
: will share other variable area.  For example, I got:
:
: c030c700 b __warned.16478
: c030c700 B mem_section
: c030c701 b __warned.16483
:
: This might cause very strange behavior.  Your patch actually fixes it.

Signed-off-by: Marcelo Roberto Jimenez <cbfee7cc2b5ad5adb7c008f3609da41bdbf85ffa@cpti.cetuc.puc-rio.br>
Cc: Atsushi Nemoto <80aeab2fcc576fb9134b563f36af765199d49e90@mba.ocn.ne.jp>
Cc: KOSAKI Motohiro <70a1d3ef3e17a2bb0f09a1b2e6c86f607ed1d6d9@jp.fujitsu.com>
Cc: Christoph Lameter <ef3ecccf258fa062c5c6521a4887d40541963af7@linux-foundation.org>
Cc: Mel Gorman <2f629c4d93e35c3d371f0463b040c6ef04a5c1e5@csn.ul.ie>
Cc: Minchan Kim <12330474acf818c36105a159b1ab0efedce0665c@gmail.com>
Cc: Yinghai Lu <0674548f4d596393408a51d6287a76ebba2f42aa@kernel.org>
Cc: Sergei Shtylyov <38a867ea26f35d3eeb42270f1bc7b9d1d135e6a2@mvista.com>
Cc: Russell King <c2093e01fa868776d7876ac617ce6d2ac30cb904@arm.linux.org.uk>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

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