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Subject: Re: [PATCH] btrfs: Use immediate assignment when referencing
 cc-option
To:     Victor Erminpour <victor.erminpour@oracle.com>, clm@fb.com
Cc:     josef@toxicpanda.com, dsterba@suse.com,
        linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1615934770-395-1-git-send-email-victor.erminpour@oracle.com>
From:   Anand Jain <anand.jain@oracle.com>
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Date:   Wed, 17 Mar 2021 10:24:04 +0800
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On 17/03/2021 06:46, Victor Erminpour wrote:
> Calling cc-option will use KBUILD_CFLAGS, which when lazy setting
> subdir-ccflags-y produces the following build error:
> 
> scripts/Makefile.lib:10: *** Recursive variable `KBUILD_CFLAGS' \
> 	references itself (eventually).  Stop.
> 
> Use := assignment to subdir-ccflags-y when referencing cc-option.
> This causes make to also evaluate += immediately, cc-option
> calls are done right away and we don't end up with KBUILD_CFLAGS
> referencing itself.
> 

Thanks for the patch.
Reviewed-by: Anand Jain <anand.jain@oracle.com>

> Signed-off-by: Victor Erminpour <victor.erminpour@oracle.com>
> ---
>   fs/btrfs/Makefile | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
> index b634c42115ea..3dba1336fa95 100644
> --- a/fs/btrfs/Makefile
> +++ b/fs/btrfs/Makefile
> @@ -7,10 +7,10 @@ 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)


> +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)


>   # The following turn off the warnings enabled by -Wextra
>   subdir-ccflags-y += -Wno-missing-field-initializers
>   subdir-ccflags-y += -Wno-sign-compare
>