On Fri, Jan 10, 2020 at 08:46:22PM +0100, David Sterba wrote:
> On Tue, Dec 17, 2019 at 04:29:54PM +0100, David Sterba wrote:
> > Separating the definitions by #ifdef looks ok, I'd rather do separate
> > definitions of ASSERT too, to avoid the ternary operator. I'll send the
> > patch.
>
> Subject: [PATCH] btrfs: separate definition of assertion failure handlers
>
> There's a report where objtool detects unreachable instructions, eg.:
>
> fs/btrfs/ctree.o: warning: objtool: btrfs_search_slot()+0x2d4: unreachable instruction
>
> This seems to be a false positive due to compiler version. The cause is
> in the ASSERT macro implementation that does the conditional check as
> IS_DEFINED(CONFIG_BTRFS_ASSERT) and not an #ifdef.
>
> To avoid that, use the ifdefs directly.
>
> CC: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Signed-off-by: David Sterba <dsterba@xxxxxxxx>
> ---
> fs/btrfs/ctree.h | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
This looks quite similar to my patch, would you mind giving me
attribution?
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 569931dd0ce5..f90b82050d2d 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -3157,17 +3157,21 @@ do { \
> rcu_read_unlock(); \
> } while (0)
>
> -__cold
> -static inline void assfail(const char *expr, const char *file, int line)
> +#ifdef CONFIG_BTRFS_ASSERT
> +__cold __noreturn
> +static inline void assertfail(const char *expr, const char *file, int line)
> {
> - if (IS_ENABLED(CONFIG_BTRFS_ASSERT)) {
> - pr_err("assertion failed: %s, in %s:%d\n", expr, file, line);
> - BUG();
> - }
> + pr_err("assertion failed: %s, in %s:%d\n", expr, file, line);
> + BUG();
assertfail() is definitely better than "assfail", but shouldn't you
update the callers so it doesn't break the build?
--
Josh
