> -----Original Message----- > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Bruce Richardson > Sent: Thursday, May 17, 2018 11:51 AM > To: Andy Green <a...@warmcat.com> > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH v4 11/23] rte_mbuf.h: explicit cast > restricting ptrdiff to uint16 > > On Mon, May 14, 2018 at 01:10:22PM +0800, Andy Green wrote: > > /projects/lagopus/src/dpdk/build/include/rte_common.h:141:34: > > warning: conversion from 'long unsigned int' to 'uint16_t' > > {aka 'short unsigned int'} may change value [-Wconversion] > > #define RTE_PTR_DIFF(ptr1, ptr2) ((uintptr_t)(ptr1) - > > (uintptr_t)(ptr2)) > > ^ > > /projects/lagopus/src/dpdk/build/include/rte_mbuf.h:1360:13: > > note: in expansion of macro 'RTE_PTR_DIFF' > > *buf_len = RTE_PTR_DIFF(shinfo, buf_addr); > > > > Signed-off-by: Andy Green <a...@warmcat.com> > > --- > > lib/librte_mbuf/rte_mbuf.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h > > index a27dbb878..0580ec8a0 100644 > > --- a/lib/librte_mbuf/rte_mbuf.h > > +++ b/lib/librte_mbuf/rte_mbuf.h > > @@ -1358,7 +1358,7 @@ rte_pktmbuf_ext_shinfo_init_helper(void *buf_addr, > > uint16_t *buf_len, > > shinfo->fcb_opaque = fcb_opaque; > > rte_mbuf_ext_refcnt_set(shinfo, 1); > > > > - *buf_len = RTE_PTR_DIFF(shinfo, buf_addr); > > + *buf_len = (uint16_t)RTE_PTR_DIFF(shinfo, buf_addr); > > return shinfo; > > } > Acked-by: Bruce Richardson <bruce.richard...@intel.com>
Just as a nit: if all such conversions are unavoidable - might be introduce: RTE_PTR_DIFF_TYPE(.., type) ((type)(RTE_PTR_DIFF(...)) Might look a bit nicer. Konstantin
