Hi, On Wed, Aug 21, 2019 at 01:37:09PM +0200, Enrico Weigelt, metux IT consult wrote: > On 20.08.19 16:22, Pali Rohár wrote: > > Hi, > > > > In that case, wouldn't a comment be more suitable for that ? > > > > And why to add comment if current state of code is more-readable and > > does not need it? > > Readability is probably a bit subjective :p > > With ongoing efforts of automatically identifying redundant code pathes, > the current situation causes the same discussion coming up over and over > again. Sooner or later somebody might get the idea to add a comment on > that line, that it's exactly as intented :o > > OTOH, I'm unsure whether it's important to document that is particular > error path is unlikely, while we don't do it in thousands of other > places. IMHO, error pathes are supposed to be unlikely by nature, > otherwise we wouldn't call it an error situation ;-) > > > People normally add comments to code which is problematic to understand > > or is somehow tricky, no so obvious or document how should code behave. > > Yes, but isn't this case so obvious that it doesn't need any > documentation at all ? Is it so important to never ever forget that this > particular path is a rare situation ? Because if I see "if (IS_ERR(...))" in an interrupt path I will try to see if it can be optimized out, but in this particular case we document it with explicit "unlikely" and I know that I do not need to bother. The fact that there is unlikely in IS_ERR is an implementation detail. It may be gone tomorrow. I do not want to have to remember all implementation details of all kernel APIs and readjust the code all the time as they are change underneath me. Thanks. -- Dmitry
