Messages in this thread | | | Date | Thu, 27 Aug 2020 22:36:36 +0100 | From | Al Viro <> | Subject | Re: [PATCH] linux/kernel.h: add container_from() |
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On Thu, Aug 27, 2020 at 01:46:33PM -0700, Linus Torvalds wrote:
> You really have to pick some pretty excessive type names (or variable > names) to get close to 80 characters. Again, to pick an example: > > struct timer_group_priv *priv = container_of(handle, > struct timer_group_priv, timer[handle->num]); > > ends up being long even if you were to split it, but that funky > container_from() wouldn't have helped the real problem - the fact that > the above is complex and nasty. > > And I had to _search_ for that example. All the normal cases of > split-line container-of's were due to doing it with the declaration, > or beause the first argument ended up being an expression in itself > and the nested expressions made it more complex.
Speaking of searching, this kind of typeof use is, IMO, actively harmful - it makes finding the places where we might get from e.g. linked list to containing objects much harder. container_of (unless combined with obfuscating use of typeof()) at least gives you a chance to grep - struct foo *not* followed by '*' is a pattern that doesn't give too many false positives. This one, OTOH, is essentially impossible to grep for.
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