kernel_optimize_test/arch/um
FUJITA Tomonori d911202e3f uml: define CONFIG_NO_DMA
I think that it's better to detect DMA misuse at build time rather than
calling BUG_ON.  Architectures that can't do DMA need to define
CONFIG_NO_DMA.

Thanks to Sam Ravnborg for explaining how CONFIG_NO_DMA and CONFIG_HAS_DMA
work:

http://marc.info/?l=linux-kernel&m=128359913825550&w=2

HAS_DMA is defined like this:

config HAS_DMA
        boolean
        depends on !NO_DMA
        default y

So to set HAS_DMA to true an arch should do:
1) Do not define NO_DMA
2) Define NO_DMA abd set it to 'n'

Must archs - including um - used principle 1).

In the um case we want to say that we do NOT have any DMA.
This can be done in two ways.
a) define NO_DMA and set it to 'y'
b) redefine HAS_DMA and set it to 'n'.

The patch you provided used principle b) where other archs use principle a).
So I suggest you should use principle a) for um too.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:12 -07:00
..
drivers Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl 2010-10-22 10:52:56 -07:00
include uml: define CONFIG_NO_DMA 2010-10-26 16:52:12 -07:00
kernel um: remove PAGE_SIZE alignment in linker script causing kernel segfault. 2010-10-26 16:52:04 -07:00
os-Linux um: fix global timer issue when using CONFIG_NO_HZ 2010-10-26 16:52:03 -07:00
scripts uml: throw out CONFIG_MODE_TT 2007-10-16 09:43:05 -07:00
sys-i386 Merge branch 'master' into for-next 2010-04-23 02:08:44 +02:00
sys-ia64 uml: remove useless comments 2009-04-01 08:59:17 -07:00
sys-ppc elf: kill USE_ELF_CORE_DUMP 2009-12-16 07:20:12 -08:00
sys-x86_64 UML: Fix compiler warning due to missing task_struct declaration 2010-04-21 01:43:03 +02:00
.gitignore um: tell git to ignore generated files 2010-03-06 11:26:28 -08:00
defconfig uml: define CONFIG_NO_DMA 2010-10-26 16:52:12 -07:00
Kconfig.char sound: make OSS sound core optional 2008-08-29 10:06:21 +02:00
Kconfig.common time: Kill off CONFIG_GENERIC_TIME 2010-07-27 12:40:54 +02:00
Kconfig.debug uml: GPROF needs to depend on FRAME_POINTER 2008-02-05 09:44:25 -08:00
Kconfig.net uml: fix URLs in Kconfig and help strings 2008-02-05 09:44:25 -08:00
Kconfig.rest uml: kill a kconfig warning 2009-04-21 13:41:50 -07:00
Kconfig.um uml: define CONFIG_NO_DMA 2010-10-26 16:52:12 -07:00
Kconfig.x86 x86, um: get rid of arch/um/Kconfig.arch 2008-10-22 22:55:23 -07:00
Makefile kbuild: move asm-offsets.h to include/generated 2009-12-12 13:08:14 +01:00
Makefile-i386 [UML] fix gcc ICEs and unresolved externs 2008-07-07 10:53:10 -07:00
Makefile-ia64 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile-os-Linux x86, um: get rid of arch/um/os symlink 2008-10-22 22:55:22 -07:00
Makefile-ppc Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile-skas [PATCH] uml makefiles sanitized 2005-09-29 08:46:26 -07:00
Makefile-x86_64 [UML] fix gcc ICEs and unresolved externs 2008-07-07 10:53:10 -07:00