[-mm patch] fix the ROMFS_* dependencies

[Adrian Bunk <bunk@stusta.de>]

On Sun, Mar 04, 2007 at 03:35:14PM +0000, David Howells wrote:
> Adrian Bunk <bunk@stusta.de> wrote:
> 
> > Is
> > 
> > CONFIG_BLOCK=y
> > CONFIG_ROMFS_FS=y
> > CONFIG_ROMFS_ON_BLOCK=n
> > CONFIG_ROMFS_ON_MTD=y
> > 
> > a reasonable configuration that should be supported, or can we turn 
> > CONFIG_ROMFS_ON_BLOCK always on if CONFIG_BLOCK=y?
> 
> Hmmm...  I don't really know the answer to that, apart from it depends.  On a
> non-embedded device, it's entirely reasonable, I think, to turn
> CONFIG_ROMFS_ON_BLOCK on if CONFIG_BLOCK is on, no questions asked.  However,
> on an embedded device you might want the extra option.

OK, what about the patch below?

> David

cu
Adrian


<--  snip  -->


This patch:
- adds the missing dependency of ROMFS_FS on BLOCK || MTD
- disallows the illegal ROMFS_FS=y, MTD=m, ROMFS_ON_MTD=y
- ensures that at least one of ROMFS_ON_BLOCK and ROMFS_ON_MTD is always 
  enabled:
  - automatically enable ROMFS_ON_MTD if BLOCK=n
  - automatically enable ROMFS_ON_BLOCK if ROMFS_ON_MTD=n
- if EMBEDDED=n, ROMFS_ON_BLOCK is always enabled
  - the "(which may have been disabled)" that could now confuse
    users has therefore been removed from the help text

Signed-off-by: Adrian Bunk <bunk@stusta.de>

---

 fs/Kconfig |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--- linux-2.6.21-rc2-mm1/fs/Kconfig.old	2007-03-04 23:04:41.000000000 +0100
+++ linux-2.6.21-rc2-mm1/fs/Kconfig	2007-03-04 23:24:27.000000000 +0100
@@ -484,6 +484,7 @@
 
 config ROMFS_FS
 	tristate "ROM file system support"
+	depends on BLOCK || MTD
 	---help---
 	  This is a very small read-only file system mainly intended for
 	  initial ram disks of installation disks, but it could be used for
@@ -499,8 +500,9 @@
 	  answer N.
 
 config ROMFS_ON_BLOCK
-	bool "Block device-backed ROM file system support"
+	bool "Block device-backed ROM file system support" if (ROMFS_ON_MTD && EMBEDDED)
 	depends on ROMFS_FS && BLOCK
+	default y
 	help
 	  This permits ROMFS to use block devices buffered through the page
 	  cache as the medium from which to retrieve data.  It does not allow
@@ -509,14 +511,15 @@
 	  If unsure, answer Y.
 
 config ROMFS_ON_MTD
-	bool "MTD-backed ROM file system support"
-	depends on ROMFS_FS && MTD
+	bool "MTD-backed ROM file system support" if BLOCK
+	depends on ROMFS_FS
+	depends on MTD=y || (ROMFS_FS=m && MTD)
+	default y
 	help
 	  This permits ROMFS to use MTD based devices directly, without the
-	  intercession of the block layer (which may have been disabled).  It
-	  also allows direct mapping of MTD devices through romfs files under
-	  NOMMU conditions if the underlying device is directly addressable by
-	  the CPU.
+	  intercession of the block layer.  It also allows direct mapping of
+	  MTD devices through romfs files under NOMMU conditions if the
+	  underlying device is directly addressable by the CPU.
 
 	  If unsure, answer Y.