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. 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
