On Fri, Mar 17, 2017 at 5:44 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > Be that as it may; what you construct above is disgusting. Surely the > code can be refactored to not look like dog vomit? > > Also; its not immediately obvious conf->copies is 'small' and this > doesn't blow up the stack; I feel that deserves a comment somewhere. > I agree that the code is horrible. It is, in fact, exactly the same solution that was used to remove variable length arrays in structs from several of the crypto drivers a few years ago - see the definition of SHASH_DESC_ON_STACK() in "crypto/hash.h" - I did not, however, hide the horrors in a macro preferring to leave the implementation visible as a warning to whoever might touch the code next. I believe that the actual stack usage is exactly the same as it was previously. I can certainly wrap this up in a macro and add comments with appropriately dire warnings in it if you feel that is both necessary and sufficient.
