From mboxrd@z Thu Jan  1 00:00:00 1970
From: der.herr@hofr.at (Nicholas Mc Guire)
Date: Sat, 18 Jun 2016 08:44:39 +0000
Subject: Coding style quesion
Message-ID: <20160618084439.GA3748@osadl.at>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org


HI !

 Stumbled across the somewhat inconsistent treatement of functions returning ERR_PTR()
 in the kernel with respect to coding style, while trying to write some static code 
 checks. The two forms which seem comon are:

                if (PTR_ERR(var) == -EINVAL) {
 and
                if (var == ERR_PTR(-EINVAL)) {

 of which I think the first is the intended construct.

 my understanding of ERR_PTR is that it is intended to be used in the form

                ret = ERR_PTR(-EINVAL);
                ...
                retrurn ret;
 or
                return ERR_PTR(-EINVAL);

 but not as in the second if() above - technically its the same thing
 Is there an "official" preference to the one or other form ? 

thx!
hofrat