Am Freitag, den 26.10.2012, 15:17 +0800 schrieb Yuanhan Liu: > On Fri, Oct 26, 2012 at 08:51:06AM +0200, Stefani Seibold wrote: > > Am Freitag, den 26.10.2012, 14:11 +0800 schrieb Yuanhan Liu: > > > On Fri, Oct 26, 2012 at 07:38:31AM +0200, Stefani Seibold wrote: > > > > Am Freitag, den 26.10.2012, 09:46 +0800 schrieb Yuanhan Liu: > > > > > From: Yuanhan Liu <[email protected]> > > > > > > > > > > Firstly, this kind of type check doesn't work. It does something > > > > > similay > > > > > like following: > > > > > void * __dummy = NULL; > > > > > __buf = __dummy; > > > > > > > > > > __dummy is defined as void *. Thus it will not trigger warnings as > > > > > expected. > > > > > > > > > > Second, we don't need that kind of check. Since the prototype > > > > > of __kfifo_out is: > > > > > unsigned int __kfifo_out(struct __kfifo *fifo, void *buf, > > > > > unsigned int len) > > > > > > > > > > buf is defined as void *, so we don't need do the type check. Remove > > > > > it. > > > > > > > > > > LINK: https://lkml.org/lkml/2012/10/25/386 > > > > > LINK: https://lkml.org/lkml/2012/10/25/584 > > > > > > > > > > Cc: Andrew Morton <[email protected]> > > > > > Cc: Wei Yang <[email protected]> > > > > > Cc: Stefani Seibold <[email protected]> > > > > > Cc: Fengguang Wu <[email protected]> > > > > > Cc: Stephen Rothwell <[email protected]> > > > > > Signed-off-by: Yuanhan Liu <[email protected]> > > > > > --- > > > > > > > > > > Did you tried to compile the whole kernel including all the drivers with > > > > your patch? > > > > > > Hi Stefani, > > > > > > I did a build test, it did't introduce any new compile errors and > > > warnings. While, I haven't tried make allmodconfig then. Does this patch > > > seems wrong to you? > > > > > > Thanks, > > > Yuanhan Liu > > > > Hi Liu, > > > > no the patch seems not wrong to me. But as you see with the previous > > patch it is not easy to predict the side effects. > > > > An allmodconfig together with C=2 is necessary to check if there is no > > side effects which current users of the kfifo API. > > Hi Stefani, > > Make with C=2 will produce tons of warnings, hard to tell it introduces > new warnings or not. I build some drivers used kfifo and samples as you > suggested with C=2, find no new warnings. I will build all drivers that > used kfifo with C=2 later, and will post the result here. >
That will be great... > > > > Also you have to build the kfifo samples, since this example code use > > all features of the kfifo API. > > > > And again: The kfifo is designed to do the many things at compile time, > > not at runtime. If you modify the code, you have to check the compiler > > assembler output for no degradation, especially in kfifo_put, kfifo_get, > > kfifo_in, kfifo_out, __kfifo_in and __kfifo_out. Prevent runtime checks > > if you can do it at compile time. This is the basic reasons to do it in > > macros. > > Is it enought to check kernel/kfifo.o only? I build that file with > and without this patch. And then dump it by objdump -D kernel/fifo.o to > /tmp/kfifo.dump.with and /tmp/kfifo.dump.without, respectively. And the > two dump file are exactly same. > No, since most of the code is inlined due performace reasons, you have to hack the kfifo examples output code for regressions and code increase. Greetings, Stefani -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
