[dpdk-dev] [PATCH 1/2] mbuf: fix bitmask of Tx offload flags

[Olivier MATZ]

On Thu, 26 Jan 2017 15:35:29 +0000, "Ananyev, Konstantin"
<konstantin.ananyev at intel.com> wrote:
> Hi Olivier,
> 
> > -----Original Message-----
> > From: Olivier MATZ [mailto:olivier.matz at 6wind.com]
> > Sent: Thursday, January 26, 2017 3:05 PM
> > To: Ananyev, Konstantin <konstantin.ananyev at intel.com>
> > Cc: Wu, Jingjing <jingjing.wu at intel.com>; dev at dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH 1/2] mbuf: fix bitmask of Tx offload
> > flags
> > 
> > On Thu, 26 Jan 2017 14:58:08 +0000, "Ananyev, Konstantin"
> > <konstantin.ananyev at intel.com> wrote:  
> > > Hi Jingjng,
> > >  
> > > > -----Original Message-----
> > > > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Jingjing Wu
> > > > Sent: Tuesday, January 24, 2017 11:48 AM
> > > > To: dev at dpdk.org
> > > > Cc: Wu, Jingjing <jingjing.wu at intel.com>
> > > > Subject: [dpdk-dev] [PATCH 1/2] mbuf: fix bitmask of Tx offload
> > > > flags
> > > >
> > > > Some Tx offload flags are missed in Bitmask of all supported
> > > > packet Tx offload features flags.
> > > > This patch fixes it.  
> > >
> > > Not sure what it exactly fixes?
> > > As I remember these flags don't specify any TX offload for HW to
> > > perform, But just provide information to the TX function.
> > > Again, why only i40e code is modified?
> > > As I remember we have the same code in other PMDs too.
> > > Konstantin
> > >  
> > > >
> > > > Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> > > > Signed-off-by: Jingjing Wu <jingjing.wu at intel.com>
> > > > ---
> > > >  lib/librte_mbuf/rte_mbuf.h | 4 ++++
> > > >  1 file changed, 4 insertions(+)
> > > >
> > > > diff --git a/lib/librte_mbuf/rte_mbuf.h
> > > > b/lib/librte_mbuf/rte_mbuf.h index bfce9f4..e57a4d2 100644
> > > > --- a/lib/librte_mbuf/rte_mbuf.h
> > > > +++ b/lib/librte_mbuf/rte_mbuf.h
> > > > @@ -295,8 +295,12 @@ extern "C" {
> > > >   */
> > > >  #define PKT_TX_OFFLOAD_MASK (    \
> > > >  		PKT_TX_IP_CKSUM |        \
> > > > +		PKT_TX_IPV4 |            \
> > > > +		PKT_TX_IPV6 |            \
> > > >  		PKT_TX_L4_MASK |         \
> > > >  		PKT_TX_OUTER_IP_CKSUM |  \
> > > > +		PKT_TX_OUTER_IPV4 |      \
> > > > +		PKT_TX_OUTER_IPV6 |      \
> > > >  		PKT_TX_TCP_SEG |         \
> > > >  		PKT_TX_QINQ_PKT |        \
> > > >  		PKT_TX_VLAN_PKT |        \
> > > > --
> > > > 2.4.11  
> > >  
> > 
> > Also, it looks like MACSEC is missing. To avoid forgetting flags in
> > the future, what do you think about doing the following (not
> > tested)?
> > 
> > 
> > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> > index b3cccfc..aa1dc76 100644
> > --- a/lib/librte_mbuf/rte_mbuf.h
> > +++ b/lib/librte_mbuf/rte_mbuf.h
> > @@ -182,9 +182,11 @@ extern "C" {
> >   */
> >  #define PKT_RX_TIMESTAMP     (1ULL << 17)
> > 
> > -/* add new RX flags here */
> > +/* add new RX flags here, and update __PKT_RX_NEXT */
> > +#define __PKT_RX_NEXT        (1ULL << 18)
> > 
> > -/* add new TX flags here */
> > +/* add new TX flags here, and update __PKT_TX_NEXT */
> > +#define __PKT_TX_NEXT        (1ULL << 43)
> > 
> >  /**
> >   * Offload the MACsec. This flag must be set by the application to
> > enable @@ -295,17 +297,16 @@ extern "C" {
> >  #define PKT_TX_OUTER_IPV6    (1ULL << 60)
> > 
> >  /**
> > + * Bitmask of all supported packet Rx offload features flags,
> > + * which can be set for packet.
> > + */
> > +#define PKT_RX_OFFLOAD_MASK (__PKT_RX_NEXT - 1)
> > +
> > +/**
> >   * Bitmask of all supported packet Tx offload features flags,
> >   * which can be set for packet.
> >   */
> > -#define PKT_TX_OFFLOAD_MASK (    \
> > -               PKT_TX_IP_CKSUM |        \
> > -               PKT_TX_L4_MASK |         \
> > -               PKT_TX_OUTER_IP_CKSUM |  \
> > -               PKT_TX_TCP_SEG |         \
> > -               PKT_TX_QINQ_PKT |        \
> > -               PKT_TX_VLAN_PKT |        \
> > -               PKT_TX_TUNNEL_MASK)
> > +#define PKT_TX_OFFLOAD_MASK ((~(__PKT_TX_NEXT - 1)) &
> > 0x1fffffffffffffff)  
> 
> I see your point but should, let say, PKT_TX_IPV4 be part of
> PKT_TX_OFFLOAD_MASK at all? It doesn't really define any offload for
> PMD/HW to perform. It just provide extra information for  PMD so it
> can successfully process other offload requests. Konstantin

Yes, that's right. On the other hand, differentiating them may confuse
the PMD developpers (that's probably the case for this patch).

Having PKT_TX_MASK that includes all TX flags automatically would also
do the job (knowing PMDs must be updated), and would avoid to forget
flags in the future... if we decide to do it, it would be better before
17.02, because PKT_TX_OFFLOAD_MASK was added after 16.11, so it is not
yet part of the API.

In any case, we need a patch to fix the missing PKT_TX_MACSEC in
PKT_TX_OFFLOAD_MASK.