On Fri, 7 Jun 2019 16:59:32 +0000 "Ananyev, Konstantin" <konstantin.anan...@intel.com> wrote:
> > -----Original Message----- > > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Stephen Hemminger > > Sent: Wednesday, June 5, 2019 7:10 PM > > To: dev@dpdk.org > > Cc: Richardson, Bruce <bruce.richard...@intel.com>; Stephen Hemminger > > <step...@networkplumber.org>; Andrew Rybchenko > > <arybche...@solarflare.com> > > Subject: [dpdk-dev] [PATCH v4 5/8] net/ether: mark ethernet addresses as > > being 2-byte aligned > > > > From: Bruce Richardson <bruce.richard...@intel.com> > > > > When including the rte_ether.h header in applications with warnings > > enabled, a warning was given because of the assumption of 2-byte alignment > > of ethernet addresses when processing them. > > > > .../include/rte_ether.h:149:2: warning: converting a packed ‘const > > struct ether_addr’ pointer (alignment 1) to a ‘unaligned_uint16_t’ > > {aka ‘const short unsigned int’} pointer (alignment 2) may result in > > an unaligned pointer value [-Waddress-of-packed-member] > > 149 | const unaligned_uint16_t *ea_words = (const unaligned_uint16_t *)ea; > > | ^~~~~ > > > > Since ethernet addresses should always be aligned on a two-byte boundary, > > we can just inform the compiler of this assumption to remove the warnings > > and allow us to always access the addresses using 16-bit operations. > > > > Signed-off-by: Bruce Richardson <bruce.richard...@intel.com> > > Signed-off-by: Stephen Hemminger <step...@networkplumber.org> > > Reviewed-by: Andrew Rybchenko <arybche...@solarflare.com> > > --- > > lib/librte_net/rte_ether.h | 11 ++++++----- > > 1 file changed, 6 insertions(+), 5 deletions(-) > > > > diff --git a/lib/librte_net/rte_ether.h b/lib/librte_net/rte_ether.h > > index feb35a33c94b..d7b76ddf63eb 100644 > > --- a/lib/librte_net/rte_ether.h > > +++ b/lib/librte_net/rte_ether.h > > @@ -58,7 +58,8 @@ extern "C" { > > * See http://standards.ieee.org/regauth/groupmac/tutorial.html > > */ > > struct rte_ether_addr { > > - uint8_t addr_bytes[RTE_ETHER_ADDR_LEN]; /**< Addr bytes in tx order */ > > + uint8_t addr_bytes[RTE_ETHER_ADDR_LEN] __rte_aligned(2); > > + /**< Addr bytes in tx order */ > > } __attribute__((__packed__)); > > Hmm, that would change layout of any struct/union that has struct > rte_ether_addr inside. > So seems like implicit ABI breakage to me. > Konstantin There was no rte_ether_addr in previous releases.
