Hi all,
On Wed, 6 Mar 2024 15:37:03 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> On Tue, 5 Mar 2024 18:48:30 -0800 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Tue, 5 Mar 2024 at 15:51, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> > >
> > > fs/coredump.c: In function 'dump_user_range':
> > > fs/coredump.c:923:40: warning: left-hand operand of comma expression has no effect [-Wunused-value]
> > > 923 | #define dump_page_copy(src, dst) ((dst), (src))
> > > | ^
> > > fs/coredump.c:948:58: note: in expansion of macro 'dump_page_copy'
> > > 948 | int stop = !dump_emit_page(cprm, dump_page_copy(page, dump_page));
> > > | ^~~~~~~~~~~~~~
> > >
> > > Introduced by commit
> > >
> > > 4630f2caafcd ("coredump: get machine check errors early rather than during iov_iter")
> >
> > Bah. If comes from that
> >
> > #define dump_page_copy(src,dst) ((dst),(src))
> >
> > and I did it that way because I wanted to avoid *another* warning,
> > namely the "dst not used" thing.
> >
> > But it would have probably been better to either make it an inline
> > function, or maybe an explicit cast, eg
> >
> > #define dump_page_copy(src,dst) ((void)(dst),(src))
> >
> > or whatever.
>
> This became a build failure for my i386 defconfig build, so I did this:
>
> From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Date: Wed, 6 Mar 2024 15:28:12 +1100
> Subject: [PATCH] fix up for "coredump: get machine check errors early rather
> than during iov_iter"
>
> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> ---
> fs/coredump.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/coredump.c b/fs/coredump.c
> index ea155ffee14c..5353b7ac67f2 100644
> --- a/fs/coredump.c
> +++ b/fs/coredump.c
> @@ -920,7 +920,10 @@ static struct page *dump_page_copy(struct page *src, struct page *dst)
>
> #define dump_page_alloc() ((struct page *)8) // Not NULL
> #define dump_page_free(x) do { } while (0)
> -#define dump_page_copy(src, dst) ((dst), (src))
> +static struct page *dump_page_copy(struct page *src, struct page *dst)
> +{
> + return NULL;
> +}
>
> #endif
On second thoughts I made it return "src" instead of "NULL";
--
Cheers,
Stephen Rothwell
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