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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Mon, 1 Oct 2018 15:47:55 -0700
Message-ID: <CAKwvOdmCHEB945Lr26mWt9J7jYXDo89wUt=r0UT7mZ-WcroMLA@mail.gmail.com>
Subject: Re: [PATCH] libosd: Remove ignored __weak attribute
To:     Nathan Chancellor <natechancellor@gmail.com>
Cc:     ooo@electrozaur.com,
        "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
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On Sun, Sep 30, 2018 at 1:55 PM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> Clang warns that the __weak attribute is going to be ignored on
> osd_root_object because it's not in the correct location (needs to be
> after the type).
>
> ./include/scsi/osd_types.h:31:21: warning: 'weak' attribute only applies
> to variables, functions, and classes [-Wignored-attributes]
> static const struct __weak osd_obj_id osd_root_object = {0, 0};
>                     ^
>
> Turns out that GCC ignores the attribute too albeit silently because
> moving the attribute after either osd_obj_id or osd_root_object like
> all other uses of __weak on variables in the kernel causes a build
> error on both GCC and Clang because static variables cannot be weak
> since weak definitions rely on not having internal linkage:
>
> ./include/scsi/osd_types.h:31:32: error: weak declaration cannot have
> internal linkage
> static const struct osd_obj_id __weak osd_root_object = {0, 0};
>                                ^
>
> Just remove the attribute because it hasn't been correct since the
> initial addition of this file in commit de258bf5e638 ("[SCSI] libosd:
> OSDv1 Headers").
>
> Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  include/scsi/osd_types.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/scsi/osd_types.h b/include/scsi/osd_types.h
> index 48e8a165e136..6b6fdcafa6cc 100644
> --- a/include/scsi/osd_types.h
> +++ b/include/scsi/osd_types.h
> @@ -28,7 +28,7 @@ struct osd_obj_id {
>         osd_id id;
>  };
>
> -static const struct __weak osd_obj_id osd_root_object = {0, 0};
> +static const struct osd_obj_id osd_root_object = {0, 0};
>
>  struct osd_attr {
>         u32 attr_page;
> --
> 2.19.0
>

LGTM, thank you for sending, Nathan.
-- 
Thanks,
~Nick Desaulniers