From d911202e3f722c29065942400ea108b7096bdac7 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Tue, 26 Oct 2010 14:22:18 -0700 Subject: 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 Cc: Miklos Szeredi Cc: Jeff Dike Cc: Sam Ravnborg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/defconfig | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/um/defconfig') diff --git a/arch/um/defconfig b/arch/um/defconfig index 6bd456f96f9..564f3de65b4 100644 --- a/arch/um/defconfig +++ b/arch/um/defconfig @@ -566,7 +566,6 @@ CONFIG_CRC32=m # CONFIG_CRC7 is not set # CONFIG_LIBCRC32C is not set CONFIG_PLIST=y -CONFIG_HAS_DMA=y # # SCSI device support -- cgit v1.2.2