Messages in this thread | | | Date | Thu, 15 May 2014 15:36:20 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] mm, hugetlb: move the error handle logic out of normal code path |
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On Thu, 15 May 2014 11:01:42 +0200 Michal Hocko <mhocko@suse.cz> wrote:
> On Wed 14-05-14 15:10:59, Jianyu Zhan wrote: > > alloc_huge_page() now mixes normal code path with error handle logic. > > This patches move out the error handle logic, to make normal code > > path more clean and redue code duplicate. > > I don't know. Part of the function returns and cleans up on its own and > other part relies on clean up labels. This is not so much nicer than the > previous state.
That's actually a common pattern:
foo() { if (check which doesn't change any state) return -Efoo; if (another check which doesn't change any state) return -Ebar;
do_something_which_changes_state() if (another check) goto undo_that_state_chage; ...
undo_that_state_change: ... }
This ties into the main reason why we use all these gotos: to support evolution of the code. With multiple return points we risk later adding resource leaks and locking errors. Plus the code becomes more and more duplicative and spaghettified.
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