On 03/24/2015 04:16 PM, Elliott, Robert (Server Storage) wrote: > > It was a reply to the original post on 2014-10-16, not the resend > this month. > > From http://permalink.gmane.org/gmane.linux.kernel/1808168: > > kcalloc is helpful when one of the values is a variable that > might cause the multiply to overflow during runtime. Here, > two constants are being multiplied together, which can > be done and checked by the compiler at compile time. > > Since kcalloc and kmalloc_array are both static inline > functions: > static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) > { > if (size != 0 && n > SIZE_MAX / size) > return NULL; > return __kmalloc(n * size, flags); > } > static inline void *kcalloc(size_t n, size_t size, gfp_t flags) > { > return kmalloc_array(n, size, flags | __GFP_ZERO); > } > > a compiler that detects an overflow will probably just reduce > that to an inlined "return NULL." > > BUILD_BUG_ON could be used to trigger a compile-time error, > instead of building a kernel that returns a run-time error.
Ok, I hope we agree to get back to kzalloc() for which the compiler won't miss size_t overflows. Thanks for the reviews! Michael. -- Michael Opdenacker, CEO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com +33 484 258 098 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
