On 08/01/2016 02:02 AM, Arnd Bergmann wrote: > On Sunday, July 31, 2016 4:48:44 PM CEST Arvind Yadav wrote: >> IS_ERR_VALUE() assumes that parameter is an unsigned long. >> It can not be used to check if 'unsigned int' is passed insted. >> Which tends to reflect an error. >> >> In 64bit architectures sizeof (int) == 4 && sizeof (long) == 8. >> IS_ERR_VALUE(x) is ((x) >= (unsigned long)-4095). >> >> IS_ERR_VALUE() of 'unsigned int' is always false because the 32bit >> value is zero extended to 64 bits. >> >> Value of (unsigned int)-4095 is always less than value of >> (unsigned long)-4095. >> >> Now We are taking only first 32 bit for error checking rest of the 32 bit >> we ignore such that we get appropriate comparison on 64bit system as well. > > This is completely wrong: if you have a valid 64-bit pointer like > 0x00001234ffffff00, this will be interpreted as an error now. > >> First 32bit of Value of (unsigned int)-4095 and (unsigned long)-4095 will >> be equal. >> >> Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx> >> --- >> include/linux/err.h | 12 +++++++++++- >> 1 file changed, 11 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/err.h b/include/linux/err.h >> index 1e35588..c2a2789 100644 >> --- a/include/linux/err.h >> +++ b/include/linux/err.h >> @@ -18,7 +18,17 @@ >> >> #ifndef __ASSEMBLY__ >> >> -#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) >> +#define IS_ERR_VALUE(x) unlikely(is_error_check(x)) >> + >> +static inline int is_error_check(unsigned long error) > > Please leave the existing macro alone. I think you were looking for > something specific to the return code of qe_muram_alloc() function, > so please add a helper in that subsystem if you need it, not in > the generic header files. qe_muram_alloc (a.k.a. cpm_muram_alloc) returns unsigned long. The problem is certain callers that store the return value in a u32. Why not just fix those callers to store it in unsigned long (at least until error checking is done)? -Scott -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
