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[24.6.151.244]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-229785adae3sm88909645ad.16.2025.04.07.19.17.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Apr 2025 19:17:39 -0700 (PDT) Date: Mon, 7 Apr 2025 19:17:36 -0700 From: Joe Damato To: Jakub Kicinski Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, sdf@fomichev.me, hramamurthy@google.com, kuniyu@amazon.com Subject: Re: [PATCH net-next 2/8] net: designate XSK pool pointers in queues as "ops protected" Message-ID: Mail-Followup-To: Joe Damato , Jakub Kicinski , davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, sdf@fomichev.me, hramamurthy@google.com, kuniyu@amazon.com References: <20250407190117.16528-1-kuba@kernel.org> <20250407190117.16528-3-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250407190117.16528-3-kuba@kernel.org> On Mon, Apr 07, 2025 at 12:01:11PM -0700, Jakub Kicinski wrote: > Read accesses go via xsk_get_pool_from_qid(), the call coming > from the core and gve look safe (other "ops locked" drivers > don't support XSK). > > Write accesses go via xsk_reg_pool_at_qid() and xsk_clear_pool_at_qid(). > Former is already under the ops lock, latter needs to be locked when > coming from the workqueue via xp_clear_dev(). > > Acked-by: Stanislav Fomichev > Signed-off-by: Jakub Kicinski > Signed-off-by: Stanislav Fomichev > --- > include/linux/netdevice.h | 1 + > include/net/netdev_rx_queue.h | 6 +++--- > net/xdp/xsk.c | 2 ++ > net/xdp/xsk_buff_pool.c | 7 ++++++- > 4 files changed, 12 insertions(+), 4 deletions(-) [...] > diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c > index 25a76c5ce0f1..c7e50fd86c6a 100644 > --- a/net/xdp/xsk_buff_pool.c > +++ b/net/xdp/xsk_buff_pool.c > @@ -279,9 +279,14 @@ static void xp_release_deferred(struct work_struct *work) > { > struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool, > work); > + struct net_device *netdev = pool->netdev; > > rtnl_lock(); > - xp_clear_dev(pool); > + if (netdev) { > + netdev_lock_ops(netdev); > + xp_clear_dev(pool); > + netdev_unlock_ops(netdev); > + } > rtnl_unlock(); Is it actually possible for netdev to be NULL here? I feel like it probably isn't, but if it were possible we'd need an else case here to xp_clear_dev(pool) without the netdev_lock_ops?