Subject: Re: [PATCH bpf v2] xsk: inherit need_wakeup flag for shared sockets

From: Maciej Fijalkowski <[email-masked]>
Date: Wed, 21 Sep 2022 14:16:39 +0200

On Tue, Sep 20, 2022 at 03:34:19PM +0200, Magnus Karlsson wrote:
> On Tue, Sep 20, 2022 at 1:58 PM Jalal Mostafa
> <[email-masked]> wrote:
> >
> > The flag for need_wakeup is not set for xsks with `XDP_SHARED_UMEM`
> > flag and of different queue ids and/or devices. They should inherit
> > the flag from the first socket buffer pool since no flags can be
> > specified once `XDP_SHARED_UMEM` is specified. The issue is fixed
> > by creating a new function `xp_create_and_assign_umem_shared` to
> > create xsk_buff_pool for xsks with the shared umem flag set.

Hi Jalal,

Please update commit msg and remove reference to the new function that you
were creating on v1.

> 
> Thanks!
> 
> Acked-by: Magnus Karlsson <[email-masked]>
> 
> > Fixes: b5aea28dca134 ("xsk: Add shared umem support between queue ids")
> > Signed-off-by: Jalal Mostafa <[email-masked]>
> > ---
> >  include/net/xsk_buff_pool.h | 2 +-
> >  net/xdp/xsk.c               | 4 ++--
> >  net/xdp/xsk_buff_pool.c     | 5 +++--
> >  3 files changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
> > index 647722e847b4..f787c3f524b0 100644
> > --- a/include/net/xsk_buff_pool.h
> > +++ b/include/net/xsk_buff_pool.h
> > @@ -95,7 +95,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
> >                                                 struct xdp_umem *umem);
> >  int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *dev,
> >                   u16 queue_id, u16 flags);
> > -int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_umem *umem,
> > +int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_sock *umem_xs,
> >                          struct net_device *dev, u16 queue_id);
> >  int xp_alloc_tx_descs(struct xsk_buff_pool *pool, struct xdp_sock *xs);
> >  void xp_destroy(struct xsk_buff_pool *pool);
> > diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> > index 5b4ce6ba1bc7..7bada4e8460b 100644
> > --- a/net/xdp/xsk.c
> > +++ b/net/xdp/xsk.c
> > @@ -954,8 +954,8 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
> >                                 goto out_unlock;
> >                         }
> >
> > -                       err = xp_assign_dev_shared(xs->pool, umem_xs->umem,
> > -                                                  dev, qid);
> > +                       err = xp_assign_dev_shared(xs->pool, umem_xs, dev,
> > +                                                  qid);
> >                         if (err) {
> >                                 xp_destroy(xs->pool);
> >                                 xs->pool = NULL;
> > diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
> > index a71a8c6edf55..ed6c71826d31 100644
> > --- a/net/xdp/xsk_buff_pool.c
> > +++ b/net/xdp/xsk_buff_pool.c
> > @@ -212,17 +212,18 @@ int xp_assign_dev(struct xsk_buff_pool *pool,
> >         return err;
> >  }
> >
> > -int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_umem *umem,
> > +int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_sock *umem_xs,
> >                          struct net_device *dev, u16 queue_id)
> >  {
> >         u16 flags;
> > +       struct xdp_umem *umem = umem_xs->umem;
> >
> >         /* One fill and completion ring required for each queue id. */
> >         if (!pool->fq || !pool->cq)
> >                 return -EINVAL;
> >
> >         flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY;
> > -       if (pool->uses_need_wakeup)
> > +       if (umem_xs->pool->uses_need_wakeup)
> >                 flags |= XDP_USE_NEED_WAKEUP;
> >
> >         return xp_assign_dev(pool, dev, queue_id, flags);
> > --
> > 2.34.1
> >