[dpdk-dev,v4,11/23] rte_mbuf.h: explicit cast restricting ptrdiff to uint16
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Commit Message
/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 <andy@warmcat.com>
---
lib/librte_mbuf/rte_mbuf.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Comments
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 <andy@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.richardson@intel.com>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson
> Sent: Thursday, May 17, 2018 11:51 AM
> To: Andy Green <andy@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 <andy@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.richardson@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
@@ -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;
}