Messages in this thread |  | | Date | Thu, 10 Jan 2013 15:12:23 +0800 | From | Yuanhan Liu <> | Subject | Re: [PATCH 1/5] kfifo: remove unnecessary type check |
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On Wed, Jan 09, 2013 at 04:29:39PM +0100, Stefani Seibold wrote: > Am Mittwoch, den 09.01.2013, 10:35 +0800 schrieb Yuanhan Liu: > > On Tue, Jan 08, 2013 at 10:51:04PM +0100, Stefani Seibold wrote: > > > Am Dienstag, den 08.01.2013, 22:57 +0800 schrieb Yuanhan Liu: > > > > Firstly, this kind of type check doesn't work. It does something similar > > > > as 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. > > > > > > > > > > Thats wrong. > > > > > > First the type checking will be used in kfifo_put() and kfifo_in() for > > > const types to check if the passed type of the data can converted to the > > > fifo element type. > > > > Hi Stefani, > > > > Yes, I see now. After rechecking the code, I found that this kind of > > type checking only works for those static defined kifo by > > DECLARE/DEFINE_KFIFO. As the ptrtype is the same as the data type: > > > > /* the 4th argument "type" is "ptrtype" */ > > #define STRUCT_KFIFO(type, size) struct __STRUCT_KFIFO(type, size, 0, type) > > > > #define DECLARE_KFIFO(fifo, type, size) STRUCT_KFIFO(type, size) fifo > > > > While, for those kfifo dynamically allocated, the type checking will not > > work as expected then as ptrtype is always "void": > > > > struct kfifo __STRUCT_KFIFO_PTR(unsigned char, 0, void); > > > > You should avoid using struct kfifo, as you can read in kfifo.h this is > only for compatibility reason.
Well, the fact is struct kfifo is used far more widely than DECLARE/DEFINE_KFIFO; say above 50 vs less than 10.
Thanks.
--yliu > > If you use the macro DECLARE_KFIFO_PTR(), DECLARE_KFIFO() or > DEFINE_KFIFO() instead. > > Have a look at the examples files in the samples/kfifo directory. > > - Stefani >
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