Coding style quesion

Nicholas Mc Guire der.herr at
Sat Jun 18 04:44:39 EDT 2016

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) {
                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;
                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 ? 


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