RE: [PATCH net-next] netdevsim: check return value of debugfs_create_dir

["Prashant Bhole" <bhole_prashant_q7@lab.ntt.co.jp>]

> From: Jakub Kicinski [mailto:jakub.kicinski@netronome.com]
> 
> On Thu, 7 Dec 2017 13:10:39 +0900, Prashant Bhole wrote:
> > > From: Jakub Kicinski [mailto:jakub.kicinski@netronome.com]
> > >
> > > On Thu,  7 Dec 2017 10:02:13 +0900, Prashant Bhole wrote:
> > > > - Handled debugfs_create_dir failure in nsim_init()
> > > > - Fixed return value of nsim_module_init() when debugfs_create_dir
> > > > fails
> > > >
> > > > Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
> > >
> > > Why?  Failing to expose the state via DebugFS is not fatal to the
driver.
> >
> > Ok, my intention was to handle the return code properly, which is not
> > needed as per your comment.
> > Shall I remove the existing handling in nsim_module_init() in separate
> > patch?
> 
> I was going back and forth on the error handling quite a bit writing that
code.  In
> the end I decided to leave the module_init check and check for bpf prog
> directory.  Former one is mostly useful to make sure the is no duplicate
directory
> with the same name, the latter to limit possible false positive in the
selftest..

Ok. Currently return value is checked with IS_ERR(). But when Debug FS is
enabled, debugfs_create_dir will never return error value. It returns either
NULL or a valid pointer. Shall I replace IS_ERR with NULL check or
IS_ERR_OR_NULL check?

-Prashant