From patchwork Fri Dec 15 17:07:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13494671 X-Patchwork-Delegate: kuba@kernel.org Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ACD1B59E59; Fri, 15 Dec 2023 17:10:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="JtWcWrlR"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="NzCo4hAy" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1702660241; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zae3m1cO9fSJoSwUDjCnhvMwaD0Cp7wkXYtacLoccYI=; b=JtWcWrlRr/Yw4kQ1UWySiE1WnFklIBcg9wCnilSSfcJDNnaXHknsfFQ2hm3Wg/ONikWDB+ WRxCE/Tc1oj8/5Vra+uDd80anJKj5JKArhylRiQWeqOiu9dGS2spg5Z1FiJFb7PYir9ZLl YgPOBKKzrgsCa96PnNswic05kIQ/rUSbCdeqFC5thljdEb55zV5ywwfj1sceBkMTCRU0p4 y7xHwZ+cy0+IUt7MuLeHRIi5cN42VqdLlD8SLMT0QybC5HYV7wrPuUzJG43qDI9Xt9mesD 1NDCCGSXDR+g3yntLA8aFfivSR8gLveMOz0FQOgX4TMdKDdRnyy3zgJi+xJuvw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1702660241; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zae3m1cO9fSJoSwUDjCnhvMwaD0Cp7wkXYtacLoccYI=; b=NzCo4hAyNx+4VtNSo05p7oXiKzL7azy7XiXo4Ljk4IPRdRDvvQB9bLy3+o8Xz+b/cRIMks tfLo+tJk/hEPGUCQ== To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: "David S. Miller" , Boqun Feng , Daniel Borkmann , Eric Dumazet , Frederic Weisbecker , Ingo Molnar , Jakub Kicinski , Paolo Abeni , Peter Zijlstra , Thomas Gleixner , Waiman Long , Will Deacon , Sebastian Andrzej Siewior , "K. Y. Srinivasan" , Alexei Starovoitov , AngeloGioacchino Del Regno , Dexuan Cui , Dimitris Michailidis , Felix Fietkau , Haiyang Zhang , Horatiu Vultur , Jeroen de Borst , Jesper Dangaard Brouer , John Crispin , John Fastabend , Lorenzo Bianconi , Mark Lee , Matthias Brugger , Praveen Kaligineedi , Sean Wang , Shailend Chand , UNGLinuxDriver@microchip.com, Wei Liu , bpf@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-mediatek@lists.infradead.org Subject: [PATCH net-next 19/24] net: fungible, gve, mtk, microchip, mana: Use nested-BH locking for XDP redirect. Date: Fri, 15 Dec 2023 18:07:38 +0100 Message-ID: <20231215171020.687342-20-bigeasy@linutronix.de> In-Reply-To: <20231215171020.687342-1-bigeasy@linutronix.de> References: <20231215171020.687342-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org The per-CPU variables used during bpf_prog_run_xdp() invocation and later during xdp_do_redirect() rely on disabled BH for their protection. Without locking in local_bh_disable() on PREEMPT_RT these data structure require explicit locking. This is a follow-up on the previous change which introduced bpf_run_lock.redirect_lock and uses it now within drivers. The simple way is to acquire the lock before bpf_prog_run_xdp() is invoked and hold it until the end of function. This does not always work because some drivers (cpsw, atlantic) invoke xdp_do_flush() in the same context. Acquiring the lock in bpf_prog_run_xdp() and dropping in xdp_do_redirect() (without touching drivers) does not work because not all driver, which use bpf_prog_run_xdp(), do support XDP_REDIRECT (and invoke xdp_do_redirect()). Ideally the minimal locking scope would be bpf_prog_run_xdp() + xdp_do_redirect() and everything else (error recovery, DMA unmapping, free/ alloc of memory, …) would happen outside of the locked section. Cc: "K. Y. Srinivasan" Cc: Alexei Starovoitov Cc: AngeloGioacchino Del Regno Cc: Dexuan Cui Cc: Dimitris Michailidis Cc: Felix Fietkau Cc: Haiyang Zhang Cc: Horatiu Vultur Cc: Jeroen de Borst Cc: Jesper Dangaard Brouer Cc: John Crispin Cc: John Fastabend Cc: Lorenzo Bianconi Cc: Mark Lee Cc: Matthias Brugger Cc: Praveen Kaligineedi Cc: Sean Wang Cc: Shailend Chand Cc: UNGLinuxDriver@microchip.com Cc: Wei Liu Cc: bpf@vger.kernel.org Cc: linux-hyperv@vger.kernel.org Cc: linux-mediatek@lists.infradead.org Signed-off-by: Sebastian Andrzej Siewior --- drivers/net/ethernet/fungible/funeth/funeth_rx.c | 1 + drivers/net/ethernet/google/gve/gve_rx.c | 12 +++++++----- drivers/net/ethernet/mediatek/mtk_eth_soc.c | 1 + drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c | 1 + drivers/net/ethernet/microsoft/mana/mana_bpf.c | 1 + 5 files changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/fungible/funeth/funeth_rx.c b/drivers/net/ethernet/fungible/funeth/funeth_rx.c index 7e2584895de39..e7b1382545908 100644 --- a/drivers/net/ethernet/fungible/funeth/funeth_rx.c +++ b/drivers/net/ethernet/fungible/funeth/funeth_rx.c @@ -152,6 +152,7 @@ static void *fun_run_xdp(struct funeth_rxq *q, skb_frag_t *frags, void *buf_va, xdp_prepare_buff(&xdp, buf_va, FUN_XDP_HEADROOM, skb_frag_size(frags) - (FUN_RX_TAILROOM + FUN_XDP_HEADROOM), false); + guard(local_lock_nested_bh)(&bpf_run_lock.redirect_lock); xdp_prog = READ_ONCE(q->xdp_prog); act = bpf_prog_run_xdp(xdp_prog, &xdp); diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c index 73655347902d2..504c8ef761a33 100644 --- a/drivers/net/ethernet/google/gve/gve_rx.c +++ b/drivers/net/ethernet/google/gve/gve_rx.c @@ -779,11 +779,13 @@ static void gve_rx(struct gve_rx_ring *rx, netdev_features_t feat, page_info->page_offset, GVE_RX_PAD, len, false); old_data = xdp.data; - xdp_act = bpf_prog_run_xdp(xprog, &xdp); - if (xdp_act != XDP_PASS) { - gve_xdp_done(priv, rx, &xdp, xprog, xdp_act); - ctx->total_size += frag_size; - goto finish_ok_pkt; + scoped_guard(local_lock_nested_bh, &bpf_run_lock.redirect_lock) { + xdp_act = bpf_prog_run_xdp(xprog, &xdp); + if (xdp_act != XDP_PASS) { + gve_xdp_done(priv, rx, &xdp, xprog, xdp_act); + ctx->total_size += frag_size; + goto finish_ok_pkt; + } } page_info->pad += xdp.data - old_data; diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c index 3cf6589cfdacf..477a74ee18c0a 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -1946,6 +1946,7 @@ static u32 mtk_xdp_run(struct mtk_eth *eth, struct mtk_rx_ring *ring, if (!prog) goto out; + guard(local_lock_nested_bh)(&bpf_run_lock.redirect_lock); act = bpf_prog_run_xdp(prog, xdp); switch (act) { case XDP_PASS: diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c index 9ee61db8690b4..026311af07f9e 100644 --- a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c @@ -84,6 +84,7 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len) xdp_prepare_buff(&xdp, page_address(page), IFH_LEN_BYTES + XDP_PACKET_HEADROOM, data_len - IFH_LEN_BYTES, false); + guard(local_lock_nested_bh)(&bpf_run_lock.redirect_lock); act = bpf_prog_run_xdp(xdp_prog, &xdp); switch (act) { case XDP_PASS: diff --git a/drivers/net/ethernet/microsoft/mana/mana_bpf.c b/drivers/net/ethernet/microsoft/mana/mana_bpf.c index 23b1521c0df96..d465b1dd9fca0 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_bpf.c +++ b/drivers/net/ethernet/microsoft/mana/mana_bpf.c @@ -93,6 +93,7 @@ u32 mana_run_xdp(struct net_device *ndev, struct mana_rxq *rxq, xdp_init_buff(xdp, PAGE_SIZE, &rxq->xdp_rxq); xdp_prepare_buff(xdp, buf_va, XDP_PACKET_HEADROOM, pkt_len, false); + guard(local_lock_nested_bh)(&bpf_run_lock.redirect_lock); act = bpf_prog_run_xdp(prog, xdp); rx_stats = &rxq->stats;