[PATCH] kbuild: fix dependency generation

[Jan Beulich]

Commit 2e3646e51b2d6415549b310655df63e7e0d7a080 changed the way
the split config tree is built, but failed to also adjust fixdep
accordingly - if changing a config option from or to m, files
referencing the respective CONFIG_..._MODULE (but not the
corresponding CONFIG_...) didn't get rebuilt.

The problem is that trisate symbol are represent with three
different symbols:
SYMBOL=n => no symbol defined
SYMBOL=y => CONFIG_SYMBOL defined to '1'
SYMBOL=m => CONFIG_SYMBOL_MODULE defined to '1'

But conf_split_config do not distingush between the =y and =m case,
so only the =y case is honoured.
This is fixed in fixdep so when a CONFIG symbol with
_MODULE is found we skip that part and only look
for the CONFIG_SYMBOL version.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
---
 scripts/basic/fixdep.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
index 668a11a..6bc7e7c 100644
--- a/scripts/basic/fixdep.c
+++ b/scripts/basic/fixdep.c
@@ -28,9 +28,11 @@
  * the dependency on linux/autoconf.h by a dependency on every config
  * option which is mentioned in any of the listed prequisites.
  *
- * To be exact, split-include populates a tree in include/config/,
- * e.g. include/config/his/driver.h, which contains the #define/#undef
- * for the CONFIG_HIS_DRIVER option.
+ * kconfig populates a tree in include/config/ with an empty file
+ * for each config symbol and when the configuration is updated
+ * the files representing changed config options are touched
+ * which then let make pick up the changes and the files that use
+ * the config symbols are rebuilt.
  *
  * So if the user changes his CONFIG_HIS_DRIVER option, only the objects
  * which depend on "include/linux/config/his/driver.h" will be rebuilt,
@@ -245,6 +247,8 @@ void parse_config_file(char *map, size_t len)
 		continue;
 
 	found:
+		if (!memcmp(q - 7, "_MODULE", 7))
+			q -= 7;
 		use_config(p+7, q-p-7);
 	}
 }
-- 
1.5.1.rc3.20.gaa453

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