Messages in this thread | | | Date | Thu, 19 Nov 2020 17:03:40 +0000 | From | Christoph Hellwig <> | Subject | Re: [PATCH 2/2] iov_iter: optimise iter type checking |
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On Thu, Nov 19, 2020 at 03:29:43PM +0000, Pavel Begunkov wrote: > The problem here is that iov_iter_is_*() helpers check types for > equality, but all iterate_* helpers do bitwise ands. This confuses > a compiler, so even if some cases were handled separately with > iov_iter_is_*(), it can't eliminate and skip unreachable branches in > following iterate*().
I think we need to kill the iov_iter_is_* helpers, renumber to not do the pointless bitmask and just check for equality (might turn into a bunch of nice switch statements actually).
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