From nobody Wed Apr 1 22:20:19 2026 Received: from smtpout-04.galae.net (smtpout-04.galae.net [185.171.202.116]) (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 2060747887F; Wed, 1 Apr 2026 16:39:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.171.202.116 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775061596; cv=none; b=aKoIkryKjRBVMuRKxjCP+5iAzQCtjzHiPadWtSul7I7m2sHR7kYo9cwNYGo4vILud+OTWg75/CE+I7fcXqwR8TjrxsXlKxghzyR0rkq5GPCL228uC3zA5lsxSLsw07cD2Roogzo18hh2Shs/bSHzrA1RTGChWnkX6ZItQSUJk5U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775061596; c=relaxed/simple; bh=u5140gH0pJdXxy8qBraOd6kg1NZiRUugpvd6QrWutqM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=G2+BRk1ZlU2GZJZLKd0meeM6V5Ku9wiQEjN7AyOVBueR69w++9MHt6EQ5iaCrvQRLrSzCszH8DUcmE1RMEamU5PyaR9sFomccgYFbVRYIuDGmhYHrTWMFT2BVNWLsKOV4Z0mqJOZx0hPCEyxn8g9/Roccmz3plmAttdiVkf/ooo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=DWxfpxqV; arc=none smtp.client-ip=185.171.202.116 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="DWxfpxqV" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-04.galae.net (Postfix) with ESMTPS id 45B11C5996D; Wed, 1 Apr 2026 16:40:19 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 342D0602BF; Wed, 1 Apr 2026 16:39:48 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 814F510450A06; Wed, 1 Apr 2026 18:39:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1775061586; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=kCgOzQ8Y4YhrvRV1+f5amWm1GBx7MYC0pnJwaV1132A=; b=DWxfpxqV7qZPqZuovoSYwxKUgaYuGgy/DqYSKxcQ0Wyc68TeJKVEro/kpir7ppjhHoG2Pc F+nLvIBRyePjRqV1Qhqw0jdpoCVZB4UMThpg0mXKQ4bwRnlFQpOO4pSQ7vR4tY00/vpMHo cakkvtFWj+URKPT2tFxVOQkbfZ+TMrE4S+u46ua+yqAUatpgKyFmDQECo4WY3/6lcP8HPz pmnoNr+Q/Sk+rl3EKvTBg/DJVH8FQbi2vIivB0sbO3t4q4YZDeAoqpHshENeA5j4ZrDxBp AhjmQwpAlGTmoQoV9ytmWFKsje9LGJDY3R86drBwGUVXYHPrOwPCPH20UkE8KA== From: =?utf-8?q?Th=C3=A9o_Lebrun?= Date: Wed, 01 Apr 2026 18:39:13 +0200 Subject: [PATCH net-next 10/11] net: macb: use context swapping in .set_ringparam() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260401-macb-context-v1-10-9590c5ab7272@bootlin.com> References: <20260401-macb-context-v1-0-9590c5ab7272@bootlin.com> In-Reply-To: <20260401-macb-context-v1-0-9590c5ab7272@bootlin.com> To: Nicolas Ferre , Claudiu Beznea , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Richard Cochran , Russell King Cc: Paolo Valerio , Conor Dooley , Nicolai Buchwitz , Vladimir Kondratiev , Gregory CLEMENT , =?utf-8?q?Beno=C3=AEt_Monin?= , Tawfik Bayouk , Thomas Petazzoni , Maxime Chevallier , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Th=C3=A9o_Lebrun?= X-Mailer: b4 0.15.0 X-Last-TLS-Session-Version: TLSv1.3 ethtool_ops.set_ringparam() is implemented using the primitive close / update ring size / reopen sequence. Under memory pressure this does not fly: we free our buffers at close and cannot reallocate new ones at open. Also, it triggers a slow PHY reinit. Instead, exploit the new context mechanism and improve our sequence to: - allocate a new context (including buffers) first - if it fails, early return without any impact to the interface - stop interface - update global state (bp, netdev, etc) - pass buffer pointers to the hardware - start interface - free old context. The HW disable sequence is inspired by macb_reset_hw() but avoids (1) setting NCR bit CLRSTAT and (2) clearing register PBUFRXCUT. The HW re-enable sequence is inspired by macb_mac_link_up(), skipping over register writes which would be redundant (because values have not changed). The generic context swapping parts are isolated into helper functions macb_context_swap_start|end(), reusable by other operations (change_mtu, set_channels, etc). Signed-off-by: Th=C3=A9o Lebrun --- drivers/net/ethernet/cadence/macb_main.c | 89 ++++++++++++++++++++++++++++= +--- 1 file changed, 82 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/etherne= t/cadence/macb_main.c index 42b19b969f3e..543356554c11 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -2905,6 +2905,76 @@ static struct macb_context *macb_context_alloc(struc= t macb *bp, return ctx; } =20 +static void macb_context_swap_start(struct macb *bp) +{ + struct macb_queue *queue; + unsigned int q; + u32 ctrl; + + /* Disable software Tx, disable HW Tx/Rx and disable NAPI. */ + + netif_tx_disable(bp->netdev); + + ctrl =3D macb_readl(bp, NCR); + macb_writel(bp, NCR, ctrl & ~(MACB_BIT(RE) | MACB_BIT(TE))); + + macb_writel(bp, TSR, -1); + macb_writel(bp, RSR, -1); + + for (q =3D 0, queue =3D bp->queues; q < bp->num_queues; ++q, ++queue) { + queue_writel(queue, IDR, -1); + queue_readl(queue, ISR); + if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE) + queue_writel(queue, ISR, -1); + } + + for (q =3D 0, queue =3D bp->queues; q < bp->num_queues; ++q, ++queue) { + napi_disable(&queue->napi_rx); + napi_disable(&queue->napi_tx); + } +} + +static void macb_context_swap_end(struct macb *bp, + struct macb_context *new_ctx) +{ + struct macb_context *old_ctx; + struct macb_queue *queue; + unsigned int q; + u32 ctrl; + + /* Swap contexts & give buffer pointers to HW. */ + + old_ctx =3D bp->ctx; + bp->ctx =3D new_ctx; + macb_init_buffers(bp); + + /* Start NAPI, HW Tx/Rx and software Tx. */ + + for (q =3D 0, queue =3D bp->queues; q < bp->num_queues; ++q, ++queue) { + napi_enable(&queue->napi_rx); + napi_enable(&queue->napi_tx); + } + + if (!(bp->caps & MACB_CAPS_MACB_IS_EMAC)) { + for (q =3D 0, queue =3D bp->queues; q < bp->num_queues; + ++q, ++queue) { + queue_writel(queue, IER, + bp->rx_intr_mask | + MACB_TX_INT_FLAGS | + MACB_BIT(HRESP)); + } + } + + ctrl =3D macb_readl(bp, NCR); + macb_writel(bp, NCR, ctrl | MACB_BIT(RE) | MACB_BIT(TE)); + + netif_tx_start_all_queues(bp->netdev); + + /* Free old context. */ + + macb_free_consistent(old_ctx); +} + static void gem_init_rx_ring(struct macb_context *ctx, unsigned int q) { struct macb_rxq *rxq =3D &ctx->rxq[q]; @@ -3819,9 +3889,10 @@ static int macb_set_ringparam(struct net_device *net= dev, struct kernel_ethtool_ringparam *kernel_ring, struct netlink_ext_ack *extack) { + unsigned int new_rx_size, new_tx_size; struct macb *bp =3D netdev_priv(netdev); - u32 new_rx_size, new_tx_size; - unsigned int reset =3D 0; + bool running =3D netif_running(netdev); + struct macb_context *new_ctx; =20 if ((ring->rx_mini_pending) || (ring->rx_jumbo_pending)) return -EINVAL; @@ -3840,16 +3911,20 @@ static int macb_set_ringparam(struct net_device *ne= tdev, return 0; } =20 - if (netif_running(bp->netdev)) { - reset =3D 1; - macb_close(bp->netdev); + if (running) { + new_ctx =3D macb_context_alloc(bp, netdev->mtu, + new_rx_size, new_tx_size); + if (IS_ERR(new_ctx)) + return PTR_ERR(new_ctx); + + macb_context_swap_start(bp); } =20 bp->configured_rx_ring_size =3D new_rx_size; bp->configured_tx_ring_size =3D new_tx_size; =20 - if (reset) - macb_open(bp->netdev); + if (running) + macb_context_swap_end(bp, new_ctx); =20 return 0; } --=20 2.53.0