Re: [PATCH] jbd: Remove redundant NULL check upon kfree()

From: Davidlohr Bueso
Date: Wed Aug 11 2010 - 09:11:51 EST


On Wed, 2010-08-11 at 15:06 +0200, Jiri Kosina wrote:
> On Wed, 11 Aug 2010, Davidlohr Bueso wrote:
>
> > jbd: Remove redundant NULL check upon kfree().
> >
> > Signed-off-by: Davidlohr Bueso <dave@xxxxxxx>
> > ---
> > fs/jbd/transaction.c | 3 +--
> > 1 files changed, 1 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
> > index 5ae71e7..5e98130 100644
> > --- a/fs/jbd/transaction.c
> > +++ b/fs/jbd/transaction.c
> > @@ -232,8 +232,7 @@ repeat_locked:
> >
> > lock_map_acquire(&handle->h_lockdep_map);
> > out:
> > - if (unlikely(new_transaction)) /* It's usually NULL */
> > - kfree(new_transaction);
> > + kfree(new_transaction);
>
> This doesn't seem entirely redundant, as it is optimized (via the
> unlikely() hint) for the opposite case than what kfree() is optimized for
> (kfree() assumes that the pointer is likely non-NULL, while the code above
> assumes that the pointer si likely NULL).
>

Ok, makes sense. I was a bit doubtful about the unlikely(), thanks for
the review.

Davidlohr

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