On Tue, Nov 05, 2019 at 12:48:16AM +0000, Mark Bloch wrote:
>
>
> On 11/3/19 11:41 PM, Greg Kroah-Hartman wrote:
> > When calling debugfs functions, there is no need to ever check the
> > return value. The function can work or not, but the code logic should
> > never do something different based on this.
> >
> > Cc: Leon Romanovsky <leon@xxxxxxxxxx>
> > Cc: Doug Ledford <dledford@xxxxxxxxxx>
> > Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/infiniband/hw/mlx5/main.c | 62 +++++++---------------------
> > drivers/infiniband/hw/mlx5/mlx5_ib.h | 9 +---
> > 2 files changed, 16 insertions(+), 55 deletions(-)
> >
> > Note, I kind of need to take this through my tree now as I broke the
> > build due to me changing the use of debugfs_create_atomic_t() in my
> > tree and not noticing this being used here. Sorry about that, any
> > objections?
> >
> > And 0-day seems really broken to have missed this for the past months,
> > ugh, I need to stop relying on it...
> >
> >
> > diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
> > index 831539419c30..059db0610445 100644
> > --- a/drivers/infiniband/hw/mlx5/main.c
> > +++ b/drivers/infiniband/hw/mlx5/main.c
> > @@ -5710,11 +5710,10 @@ static int mlx5_ib_rn_get_params(struct ib_device *device, u8 port_num,
> >
> > static void delay_drop_debugfs_cleanup(struct mlx5_ib_dev *dev)
> > {
> > - if (!dev->delay_drop.dbg)
> > + if (!dev->delay_drop.dir_debugfs)
>
> Shouldn't this be:
> if (IS_ERR(dev->delay_drop.dir_debugfs))
> return;
> ?
No, really there should not be any check at all as there is no problem
taking the result of a debugfs call and feeding it back into another
call. There is no need to check these return values at all.
So the code should just be dropped, I can do that as a follow-on if you
want me to.
> > return;
> > - debugfs_remove_recursive(dev->delay_drop.dbg->dir_debugfs);
> > - kfree(dev->delay_drop.dbg);
> > - dev->delay_drop.dbg = NULL;
> > + debugfs_remove_recursive(dev->delay_drop.dir_debugfs);
> > + dev->delay_drop.dir_debugfs = NULL;
>
> Thinking about this more, we already do something like this:
> if (IS_ERR_OR_NULL(dentry))
> return;
> inside debugfs_remove_recursive(), so this entire function can be reduced
> to just calling debugfs_remove_recursive().
Very true, I was trying to keep the patch simple :)
thanks,
greg k-h
