Re: [PATCH v2] vfs: avoid dereferencing pointers in iterate_supers callbacks

[Jeff Layton]

On Thu, 2018-05-17 at 11:26 -0700, Matthew Wilcox wrote:
> On Thu, May 17, 2018 at 01:43:36PM -0400, Jeff Layton wrote:
> > @@ -107,12 +109,10 @@ static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
> >   */
> >  void ksys_sync(void)
> >  {
> > -	int nowait = 0, wait = 1;
> > -
> >  	wakeup_flusher_threads(WB_REASON_SYNC);
> >  	iterate_supers(sync_inodes_one_sb, NULL);
> > -	iterate_supers(sync_fs_one_sb, &nowait);
> > -	iterate_supers(sync_fs_one_sb, &wait);
> > +	iterate_supers(sync_fs_one_sb, NULL);
> > +	iterate_supers(sync_fs_one_sb, (void *)1UL);
> 
> I think this is actually less clear.  How about:
> 
> 	void *wait = (void *)1UL;
> 
> 	iterate_supers(sync_fs_one_sb, !wait);
> 	iterate_supers(sync_fs_one_sb, wait);
> 

Sure, I could do that. We could also keep the wait/nowait vars too, I
guess.