Messages in this thread | | | Subject | Re: [possible PATCH] crypto: sahara - Use #ifdef DEBUG not IS_ENABLED(DEBUG) | From | Joe Perches <> | Date | Fri, 22 Mar 2019 08:07:12 -0700 |
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On Fri, 2019-03-22 at 15:29 +0100, Ard Biesheuvel wrote: > On Fri, 22 Mar 2019 at 13:43, Herbert Xu <herbert@gondor.apana.org.au> wrote: > > On Thu, Mar 07, 2019 at 04:15:55PM -0800, Joe Perches wrote: > > > Normal use of IS_ENABLED is with a CONFIG_<SYMBOL> and > > > there is no -DDEBUG in the Makefile here. > > > > > > Replace the IS_ENABLED(DEBUG) with #ifdef DEBUG/#endif > > > blocks. > > > > > > Miscellanea: > > > > > > o Move the sahara_state array into the function that uses it. > > > > > > Signed-off-by: Joe Perches <joe@perches.com> > > > --- > > > drivers/crypto/sahara.c | 20 +++++++++----------- > > > 1 file changed, 9 insertions(+), 11 deletions(-) > > > > Even if this is correct this is way too ugly. The original code > > at least compiled everything regardless of macros. Your new code > > won't detect compile errors in debugging code unless debugging is > > enabled. > > > > What's wrong with IS_ENABLED(DEBUG) anyway? It may not be 'normal use' > but it works fine.
drivers/crypto/sahara.c is the only user in the kernel tree. So only it's abnormal use. I rather like the concept actually.
IS_ENABLED is almost exclusively used with CONFIG_<FOO> symbols and it could be useful to require it to be used with CONFIG_<FOO> symbols and use some other similar mechanism for DEBUG use.
Maybe just adding a global #define in kernel.h like
#define IS_DEBUG_ENABLED IS_ENABLED(DEBUG)
to isolate this in one place might be better.
A good thing about using IS_ENABLED or the suggested IS_DEBUG_ENABLED would be that least gcc 5+ seems to automatically elide the uses of any unreferenced static const char * arrays like the sahara_state uses here.
(I don't have gcc4 anymore so I couldn't check that version)
So using 'if (IS_DEBUG_ENABLED)' could simplify some existing code like the many uses of
#ifdef DEBUG ... #endif
or equivalent
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