Re: [PATCH linux-next] autofs4: autofs4_catatonic_mode(): removeredundant null check on kfree()

[Michael Tokarev]

13.02.2013 11:20, Ian Kent wrote:
> On Tue, 2013-02-12 at 10:12 -0700, Tim Gardner wrote:
> > smatch analysis:
> >
> > fs/autofs4/waitq.c:46 autofs4_catatonic_mode() info: redundant null
> >   check on wq->name.name calling kfree()
>
> I'm not sure about this change.
>
> autofs4_catatonic_mode() could be called when there are remaining
> entries in the wait queue, which is nulled, so autofs4_wait_release()
> won't see the the discarded waits if it is called.

Ian, this is about something else really.  The patch is about the
NULL check before calling kfree() -- it does the NULL check internally.
It is nothing about code flow or anything else, it is about calling
kfree() unconditionally regardless whenever the argument is actually
NULL or non-NULL.  It makes the code shorter and easier to read.

You can add my

Signed-off-by: Michael Tokarev <mjt@xxxxxxxxxx>

if you want.

> > Cc: Ian Kent <raven@xxxxxxxxxx>
> > Cc: autofs@xxxxxxxxxxxxxxx
> > Signed-off-by: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>
> > ---
> >   fs/autofs4/waitq.c |    6 ++----
> >   1 file changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
> > index 03bc1d3..3db70da 100644
> > --- a/fs/autofs4/waitq.c
> > +++ b/fs/autofs4/waitq.c
> > @@ -42,10 +42,8 @@ void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
> >   	while (wq) {
> >   		nwq = wq->next;
> >   		wq->status = -ENOENT; /* Magic is gone - report failure */
> > -		if (wq->name.name) {
> > -			kfree(wq->name.name);
> > -			wq->name.name = NULL;
> > -		}
> > +		kfree(wq->name.name);
> > +		wq->name.name = NULL;
> >   		wq->wait_ctr--;
> >   		wake_up_interruptible(&wq->queue);
> >   		wq = nwq;
>
>
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