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authorDavid Sterba <dsterba@suse.com>2021-03-17 11:43:13 +0100
committerDavid Sterba <dsterba@suse.com>2021-03-17 19:42:18 +0100
commitebd99a6b34fbcccf21067b66d1718000feb80ce8 (patch)
tree9d22b281eb0e7fcc52d81286d99826162478e704
parent3cb894972f1809aa8d087c42e5e8b26c64b7d508 (diff)
downloadlinux-ebd99a6b34fbcccf21067b66d1718000feb80ce8.tar.bz2
btrfs: fix build when using M=fs/btrfs
There are people building the module with M= that's supposed to be used for external modules. This got broken in e9aa7c285d20 ("btrfs: enable W=1 checks for btrfs"). $ make M=fs/btrfs scripts/Makefile.lib:10: *** Recursive variable 'KBUILD_CFLAGS' references itself (eventually). Stop. make: *** [Makefile:1755: modules] Error 2 There's a difference compared to 'make fs/btrfs/btrfs.ko' which needs to rebuild a few more things and also the dependency modules need to be available. It could fail with eg. WARNING: Symbol version dump "Module.symvers" is missing. Modules may not have dependencies or modversions. In some environments it's more convenient to rebuild just the btrfs module by M= so let's make it work. The problem is with recursive variable evaluation in += so the conditional C options are stored in a temporary variable to avoid the recursion. Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/Makefile10
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index b634c42115ea..b4fb997eda16 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -7,10 +7,12 @@ subdir-ccflags-y += -Wmissing-format-attribute
subdir-ccflags-y += -Wmissing-prototypes
subdir-ccflags-y += -Wold-style-definition
subdir-ccflags-y += -Wmissing-include-dirs
-subdir-ccflags-y += $(call cc-option, -Wunused-but-set-variable)
-subdir-ccflags-y += $(call cc-option, -Wunused-const-variable)
-subdir-ccflags-y += $(call cc-option, -Wpacked-not-aligned)
-subdir-ccflags-y += $(call cc-option, -Wstringop-truncation)
+condflags := \
+ $(call cc-option, -Wunused-but-set-variable) \
+ $(call cc-option, -Wunused-const-variable) \
+ $(call cc-option, -Wpacked-not-aligned) \
+ $(call cc-option, -Wstringop-truncation)
+subdir-ccflags-y += $(condflags)
# The following turn off the warnings enabled by -Wextra
subdir-ccflags-y += -Wno-missing-field-initializers
subdir-ccflags-y += -Wno-sign-compare