Message-ID: <AM7PR04MB6885E78D44A460E49FB324AEF83F0@AM7PR04MB6885.eurprd04.prod.outlook.com>
Date:   Fri, 18 Sep 2020 09:12:50 +0000
From:   "Y.b. Lu" <yangbo.lu@....com>
To:     Saeed Mahameed <saeed@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Ioana Ciornei <ioana.ciornei@....com>,
        Ioana Ciocoi Radulescu <ruxandra.radulescu@....com>,
        Richard Cochran <richardcochran@...il.com>
Subject: RE: [v3, 5/6] dpaa2-eth: support PTP Sync packet one-step
 timestamping

Hi Saeed,

> -----Original Message-----
> From: Saeed Mahameed <saeed@...nel.org>
> Sent: Thursday, September 17, 2020 3:23 AM
> To: Y.b. Lu <yangbo.lu@....com>; netdev@...r.kernel.org
> Cc: David S . Miller <davem@...emloft.net>; Jakub Kicinski
> <kuba@...nel.org>; Ioana Ciornei <ioana.ciornei@....com>; Ioana Ciocoi
> Radulescu <ruxandra.radulescu@....com>; Richard Cochran
> <richardcochran@...il.com>
> Subject: Re: [v3, 5/6] dpaa2-eth: support PTP Sync packet one-step
> timestamping
> 
> On Wed, 2020-09-16 at 20:08 +0800, Yangbo Lu wrote:
> > This patch is to add PTP sync packet one-step timestamping support.
> > Before egress, one-step timestamping enablement needs,
> >
> > - Enabling timestamp and FAS (Frame Annotation Status) in
> >   dpni buffer layout.
> >
> > - Write timestamp to frame annotation and set PTP bit in
> >   FAS to mark as one-step timestamping event.
> >
> > - Enabling one-step timestamping by dpni_set_single_step_cfg()
> >   API, with offset provided to insert correction time on frame.
> >   The offset must respect all MAC headers, VLAN tags and other
> >   protocol headers accordingly. The correction field update can
> >   consider delays up to one second. So PTP frame needs to be
> >   filtered and parsed, and written timestamp into Sync frame
> >   originTimestamp field.
> >
> > The operation of API dpni_set_single_step_cfg() has to be done
> > when no one-step timestamping frames are in flight. So we have
> > to make sure the last one-step timestamping frame has already
> > been transmitted on hardware before starting to send the current
> > one. The resolution is,
> >
> > - Utilize skb->cb[0] to mark timestamping request per packet.
> >   If it is one-step timestamping PTP sync packet, queue to skb queue.
> >   If not, transmit immediately.
> >
> > - Schedule a work to transmit skbs in skb queue.
> >
> > - mutex lock is used to ensure the last one-step timestamping packet
> >   has already been transmitted on hardware through TX confirmation
> > queue
> >   before transmitting current packet.
> >
> > Signed-off-by: Yangbo Lu <yangbo.lu@....com>
> > ---
> > Changes for v2:
> > 	- None.
> > Changes for v3:
> > 	- Fixed build issue on 32-bit.
> > 	- Converted to use ptp_parse_header.
> > ---
> >  drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c   | 191
> > +++++++++++++++++++--
> >  drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h   |  32 +++-
> >  .../net/ethernet/freescale/dpaa2/dpaa2-ethtool.c   |   4 +-
> >  3 files changed, 211 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> > b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> > index eab9470..ba570f6 100644
> > --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> > +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/bpf.h>
> >  #include <linux/bpf_trace.h>
> >  #include <linux/fsl/ptp_qoriq.h>
> > +#include <linux/ptp_classify.h>
> >  #include <net/pkt_cls.h>
> >  #include <net/sock.h>
> >
> > @@ -563,11 +564,57 @@ static int dpaa2_eth_consume_frames(struct
> > dpaa2_eth_channel *ch,
> >  	return cleaned;
> >  }
> >
> > +static int dpaa2_eth_ptp_parse(struct sk_buff *skb,
> > +			       u8 *msgtype, u8 *twostep, u8 *udp,
> > +			       u16 *correction_offset,
> > +			       u16 *origintimestamp_offset)
> > +{
> > +	unsigned int ptp_class;
> > +	struct ptp_header *hdr;
> > +	unsigned int type;
> > +	u8 *base;
> > +
> > +	ptp_class = ptp_classify_raw(skb);
> > +	if (ptp_class == PTP_CLASS_NONE)
> > +		return -EINVAL;
> > +
> > +	hdr = ptp_parse_header(skb, ptp_class);
> > +	if (!hdr)
> > +		return -EINVAL;
> > +
> > +	*msgtype = ptp_get_msgtype(hdr, ptp_class);
> > +	*twostep = hdr->flag_field[0] & 0x2;
> > +
> > +	type = ptp_class & PTP_CLASS_PMASK;
> > +	if (type == PTP_CLASS_IPV4 ||
> > +	    type == PTP_CLASS_IPV6)
> > +		*udp = 1;
> > +	else
> > +		*udp = 0;
> > +
> > +	base = skb_mac_header(skb);
> > +	*correction_offset = (u8 *)&hdr->correction - base;
> > +	*origintimestamp_offset = (u8 *)hdr + sizeof(struct ptp_header)
> > - base;
> > +
> > +	return 0;
> > +}
> > +
> >  /* Configure the egress frame annotation for timestamp update */
> > -static void dpaa2_eth_enable_tx_tstamp(struct dpaa2_fd *fd, void
> > *buf_start)
> > +static void dpaa2_eth_enable_tx_tstamp(struct dpaa2_eth_priv *priv,
> > +				       struct dpaa2_fd *fd,
> > +				       void *buf_start,
> > +				       struct sk_buff *skb)
> >  {
> > +	struct ptp_tstamp origin_timestamp;
> > +	struct dpni_single_step_cfg cfg;
> > +	u8 msgtype, twostep, udp;
> >  	struct dpaa2_faead *faead;
> > +	struct dpaa2_fas *fas;
> > +	struct timespec64 ts;
> > +	u16 offset1, offset2;
> >  	u32 ctrl, frc;
> > +	__le64 *ns;
> > +	u8 *data;
> >
> >  	/* Mark the egress frame annotation area as valid */
> >  	frc = dpaa2_fd_get_frc(fd);
> > @@ -583,6 +630,58 @@ static void dpaa2_eth_enable_tx_tstamp(struct
> > dpaa2_fd *fd, void *buf_start)
> >  	ctrl = DPAA2_FAEAD_A2V | DPAA2_FAEAD_UPDV | DPAA2_FAEAD_UPD;
> >  	faead = dpaa2_get_faead(buf_start, true);
> >  	faead->ctrl = cpu_to_le32(ctrl);
> > +
> > +	if (skb->cb[0] == TX_TSTAMP_ONESTEP_SYNC) {
> > +		if (dpaa2_eth_ptp_parse(skb, &msgtype, &twostep, &udp,
> > +					&offset1, &offset2)) {
> > +			netdev_err(priv->net_dev,
> > +				   "bad packet for one-step
> > timestamping\n");
> 
> don't use netdev_err in data path, have a counter or
> WARN_ONCE/netdev_warn_once if you know that this shouldn't happen.

Ok. I will use WARN_ONCE instead.

> 
> > +			return;
> > +		}
> > +
> > +		if (msgtype != 0 || twostep) {
> > +			netdev_err(priv->net_dev,
> > +				   "bad packet for one-step
> > timestamping\n");
> > +			return;
> > +		}
> > +
> > +		/* Mark the frame annotation status as valid */
> > +		frc = dpaa2_fd_get_frc(fd);
> > +		dpaa2_fd_set_frc(fd, frc | DPAA2_FD_FRC_FASV);
> > +
> > +		/* Mark the PTP flag for one step timestamping */
> > +		fas = dpaa2_get_fas(buf_start, true);
> > +		fas->status = cpu_to_le32(DPAA2_FAS_PTP);
> > +
> > +		/* Write current time to FA timestamp field */
> > +		if (!dpaa2_ptp) {
> > +			netdev_err(priv->net_dev,
> > +				   "ptp driver may not loaded for one-
> > step timestamping\n");
> 
> why are you even here if dpaa2_ptp not valid ? isn't it too late to
> abort here ? some of the tx descriptor fields are already populated.
> 
> Just don't allow ptp and avoid marking skbs for timestamping as early
> as possible if your driver is not ready for it ..

Will check PTP driver availability before marking skb for timestamping.
And will check it in ioctl and ethtool get_ts_info call back too.

> 
> > +			return;
> > +		}
> > +		dpaa2_ptp->caps.gettime64(&dpaa2_ptp->caps, &ts);
> > +		ns = dpaa2_get_ts(buf_start, true);
> > +		*ns = cpu_to_le64(timespec64_to_ns(&ts) /
> > +				  DPAA2_PTP_CLK_PERIOD_NS);
> > +
> > +		/* Update current time to PTP message originTimestamp
> > field */
> > +		ns_to_ptp_tstamp(&origin_timestamp, le64_to_cpup(ns));
> > +		data = skb_mac_header(skb);
> > +		*(__be16 *)(data + offset2) =
> > htons(origin_timestamp.sec_msb);
> > +		*(__be32 *)(data + offset2 + 2) =
> > +			htonl(origin_timestamp.sec_lsb);
> > +		*(__be32 *)(data + offset2 + 6) =
> > htonl(origin_timestamp.nsec);
> > +
> > +		cfg.en = 1;
> > +		cfg.ch_update = udp;
> > +		cfg.offset = offset1;
> > +		cfg.peer_delay = 0;
> > +
> > +		if (dpni_set_single_step_cfg(priv->mc_io, 0, priv-
> > >mc_token,
> > +					     &cfg))
> > +			netdev_err(priv->net_dev,
> > +				   "dpni_set_single_step_cfg
> > failed\n");
> 
> Again too much error prints on data path, without any real useful debug
> information

Will use WARN_ONCE instead.

> 
> > +	}
> >  }
> >
> >  /* Create a frame descriptor based on a fragmented skb */
> > @@ -820,7 +919,7 @@ static int dpaa2_eth_build_single_fd(struct
> > dpaa2_eth_priv *priv,
> >   * This can be called either from dpaa2_eth_tx_conf() or on the
> > error path of
> >   * dpaa2_eth_tx().
> >   */
> > -static void dpaa2_eth_free_tx_fd(const struct dpaa2_eth_priv *priv,
> > +static void dpaa2_eth_free_tx_fd(struct dpaa2_eth_priv *priv,
> >  				 struct dpaa2_eth_fq *fq,
> >  				 const struct dpaa2_fd *fd, bool
> > in_napi)
> >  {
> > @@ -903,6 +1002,8 @@ static void dpaa2_eth_free_tx_fd(const struct
> > dpaa2_eth_priv *priv,
> >  		ns = DPAA2_PTP_CLK_PERIOD_NS * le64_to_cpup(ts);
> >  		shhwtstamps.hwtstamp = ns_to_ktime(ns);
> >  		skb_tstamp_tx(skb, &shhwtstamps);
> > +	} else if (skb->cb[0] == TX_TSTAMP_ONESTEP_SYNC) {
> > +		mutex_unlock(&priv->onestep_tstamp_lock);
> >  	}
> >
> >  	/* Free SGT buffer allocated on tx */
> > @@ -922,7 +1023,8 @@ static void dpaa2_eth_free_tx_fd(const struct
> > dpaa2_eth_priv *priv,
> >  	napi_consume_skb(skb, in_napi);
> >  }
> >
> > -static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb, struct
> > net_device *net_dev)
> > +static netdev_tx_t __dpaa2_eth_tx(struct sk_buff *skb,
> > +				  struct net_device *net_dev)
> >  {
> >  	struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
> >  	struct dpaa2_fd fd;
> > @@ -937,13 +1039,6 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff
> > *skb, struct net_device *net_dev)
> >  	int err, i;
> >  	void *swa;
> >
> > -	/* Utilize skb->cb[0] for timestamping request per skb */
> > -	skb->cb[0] = 0;
> > -
> > -	if (priv->tx_tstamp_type == HWTSTAMP_TX_ON &&
> > -	    skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)
> > -		skb->cb[0] = TX_TSTAMP;
> > -
> >  	percpu_stats = this_cpu_ptr(priv->percpu_stats);
> >  	percpu_extras = this_cpu_ptr(priv->percpu_extras);
> >
> > @@ -981,8 +1076,8 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff
> > *skb, struct net_device *net_dev)
> >  		goto err_build_fd;
> >  	}
> >
> > -	if (skb->cb[0] == TX_TSTAMP)
> > -		dpaa2_eth_enable_tx_tstamp(&fd, swa);
> > +	if (skb->cb[0])
> > +		dpaa2_eth_enable_tx_tstamp(priv, &fd, swa, skb);
> >
> >  	/* Tracing point */
> >  	trace_dpaa2_tx_fd(net_dev, &fd);
> > @@ -1037,6 +1132,58 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff
> > *skb, struct net_device *net_dev)
> >  	return NETDEV_TX_OK;
> >  }
> >
> > +static void dpaa2_eth_tx_onestep_tstamp(struct work_struct *work)
> > +{
> > +	struct dpaa2_eth_priv *priv = container_of(work, struct
> > dpaa2_eth_priv,
> > +						   tx_onestep_tstamp);
> > +	struct sk_buff *skb;
> > +
> > +	while (true) {
> > +		skb = skb_dequeue(&priv->tx_skbs);
> > +		if (!skb)
> > +			return;
> > +
> > +		mutex_lock(&priv->onestep_tstamp_lock);
> > +		__dpaa2_eth_tx(skb, priv->net_dev);
> 
> Very weird approach, at least document here where the lock is being
> released, in addition to the comment that you have on the mutex
> declaration.
> 
> > +	}
> > +}
> > +
> > +static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb, struct
> > net_device *net_dev)
> > +{
> > +	struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
> > +	u8 msgtype, twostep, udp;
> > +	u16 offset1, offset2;
> > +
> > +	/* Utilize skb->cb[0] for timestamping request per skb */
> > +	skb->cb[0] = 0;
> > +
> > +	if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
> > +		if (priv->tx_tstamp_type == HWTSTAMP_TX_ON)
> > +			skb->cb[0] = TX_TSTAMP;
> > +		else if (priv->tx_tstamp_type ==
> > HWTSTAMP_TX_ONESTEP_SYNC)
> > +			skb->cb[0] = TX_TSTAMP_ONESTEP_SYNC;
> > +	}
> > +
> > +	/* TX for one-step timestamping PTP Sync packet */
> > +	if (skb->cb[0] == TX_TSTAMP_ONESTEP_SYNC) {
> > +		if (!dpaa2_eth_ptp_parse(skb, &msgtype, &twostep, &udp,
> > +					 &offset1, &offset2))
> > +			if (msgtype == 0 && twostep == 0) {
> > +				skb_queue_tail(&priv->tx_skbs, skb);
> > +				queue_work(priv->dpaa2_ptp_wq,
> > +					   &priv->tx_onestep_tstamp);
> > +				return NETDEV_TX_OK;
> > +			}
> > +		/* Use two-step timestamping if not one-step
> > timestamping
> > +		 * PTP Sync packet
> > +		 */
> > +		skb->cb[0] = TX_TSTAMP;
> > +	}
> > +
> > +	/* TX for other packets */
> > +	return __dpaa2_eth_tx(skb, net_dev);
> > +}
> > +
> >  /* Tx confirmation frame processing routine */
> >  static void dpaa2_eth_tx_conf(struct dpaa2_eth_priv *priv,
> >  			      struct dpaa2_eth_channel *ch
> > __always_unused,
> > @@ -1906,6 +2053,7 @@ static int dpaa2_eth_ts_ioctl(struct net_device
> > *dev, struct ifreq *rq, int cmd)
> >  	switch (config.tx_type) {
> >  	case HWTSTAMP_TX_OFF:
> >  	case HWTSTAMP_TX_ON:
> > +	case HWTSTAMP_TX_ONESTEP_SYNC:
> >  		priv->tx_tstamp_type = config.tx_type;
> >  		break;
> >  	default:
> > @@ -2731,8 +2879,10 @@ static int dpaa2_eth_set_buffer_layout(struct
> > dpaa2_eth_priv *priv)
> >  	/* tx buffer */
> >  	buf_layout.private_data_size = DPAA2_ETH_SWA_SIZE;
> >  	buf_layout.pass_timestamp = true;
> > +	buf_layout.pass_frame_status = true;
> >  	buf_layout.options = DPNI_BUF_LAYOUT_OPT_PRIVATE_DATA_SIZE |
> > -			     DPNI_BUF_LAYOUT_OPT_TIMESTAMP;
> > +			     DPNI_BUF_LAYOUT_OPT_TIMESTAMP |
> > +			     DPNI_BUF_LAYOUT_OPT_FRAME_STATUS;
> >  	err = dpni_set_buffer_layout(priv->mc_io, 0, priv->mc_token,
> >  				     DPNI_QUEUE_TX, &buf_layout);
> >  	if (err) {
> > @@ -2741,7 +2891,8 @@ static int dpaa2_eth_set_buffer_layout(struct
> > dpaa2_eth_priv *priv)
> >  	}
> >
> >  	/* tx-confirm buffer */
> > -	buf_layout.options = DPNI_BUF_LAYOUT_OPT_TIMESTAMP;
> > +	buf_layout.options = DPNI_BUF_LAYOUT_OPT_TIMESTAMP |
> > +			     DPNI_BUF_LAYOUT_OPT_FRAME_STATUS;
> >  	err = dpni_set_buffer_layout(priv->mc_io, 0, priv->mc_token,
> >  				     DPNI_QUEUE_TX_CONFIRM,
> > &buf_layout);
> >  	if (err) {
> > @@ -3969,6 +4120,16 @@ static int dpaa2_eth_probe(struct
> > fsl_mc_device *dpni_dev)
> >  	priv->tx_tstamp_type = HWTSTAMP_TX_OFF;
> >  	priv->rx_tstamp = false;
> >
> > +	priv->dpaa2_ptp_wq = alloc_workqueue("dpaa2_ptp_wq", 0, 0);
> > +	if (!priv->dpaa2_ptp_wq) {
> > +		err = -ENOMEM;
> > +		goto err_wq_alloc;
> > +	}
> > +
> > +	INIT_WORK(&priv->tx_onestep_tstamp,
> > dpaa2_eth_tx_onestep_tstamp);
> > +
> > +	skb_queue_head_init(&priv->tx_skbs);
> > +
> >  	/* Obtain a MC portal */
> >  	err = fsl_mc_portal_allocate(dpni_dev,
> > FSL_MC_IO_ATOMIC_CONTEXT_PORTAL,
> >  				     &priv->mc_io);
> > @@ -4107,6 +4268,8 @@ static int dpaa2_eth_probe(struct fsl_mc_device
> > *dpni_dev)
> >  err_dpni_setup:
> >  	fsl_mc_portal_free(priv->mc_io);
> >  err_portal_alloc:
> > +	destroy_workqueue(priv->dpaa2_ptp_wq);
> > +err_wq_alloc:
> >  	dev_set_drvdata(dev, NULL);
> >  	free_netdev(net_dev);
> >
> > diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> > b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> > index e33d79e..6436fa3 100644
> > --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> > +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> > @@ -195,6 +195,24 @@ struct dpaa2_faead {
> >  #define DPAA2_FAEAD_EBDDV		0x00002000
> >  #define DPAA2_FAEAD_UPD			0x00000010
> >
> > +struct ptp_tstamp {
> > +	u16 sec_msb;
> > +	u32 sec_lsb;
> > +	u32 nsec;
> > +};
> > +
> > +static inline void ns_to_ptp_tstamp(struct ptp_tstamp *tstamp, u64
> > ns)
> > +{
> > +	u64 sec, nsec;
> > +
> > +	sec = ns;
> > +	nsec = do_div(sec, 1000000000);
> > +
> > +	tstamp->sec_lsb = sec & 0xFFFFFFFF;
> > +	tstamp->sec_msb = (sec >> 32) & 0xFFFF;
> > +	tstamp->nsec = nsec;
> > +}
> > +
> >  /* Accessors for the hardware annotation fields that we use */
> >  static inline void *dpaa2_get_hwa(void *buf_addr, bool swa)
> >  {
> > @@ -474,9 +492,21 @@ struct dpaa2_eth_priv {
> >  #endif
> >
> >  	struct dpaa2_mac *mac;
> > +	struct workqueue_struct	*dpaa2_ptp_wq;
> > +	struct work_struct	tx_onestep_tstamp;
> > +	struct sk_buff_head	tx_skbs;
> > +	/* The one-step timestamping configuration on hardware
> > +	 * registers could only be done when no one-step
> > +	 * timestamping frames are in flight. So we use a mutex
> > +	 * lock here to make sure the lock is released by last
> > +	 * one-step timestamping packet through TX confirmation
> > +	 * queue before transmit current packet.
> > +	 */
> > +	struct mutex		onestep_tstamp_lock;
> >  };
> >
> >  #define TX_TSTAMP		0x1
> > +#define TX_TSTAMP_ONESTEP_SYNC	0x2
> >
> >  #define DPAA2_RXH_SUPPORTED	(RXH_L2DA | RXH_VLAN |
> RXH_L3_PROTO \
> >  				| RXH_IP_SRC | RXH_IP_DST |
> > RXH_L4_B_0_1 \
> > @@ -581,7 +611,7 @@ static inline unsigned int
> > dpaa2_eth_needed_headroom(struct sk_buff *skb)
> >  		return 0;
> >
> >  	/* If we have Tx timestamping, need 128B hardware annotation */
> > -	if (skb->cb[0] == TX_TSTAMP)
> > +	if (skb->cb[0])
> >  		headroom += DPAA2_ETH_TX_HWA_SIZE;
> >
> >  	return headroom;
> > diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> > b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> > index 26bd99b..bf3baf6 100644
> > --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> > +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> > @@ -1,6 +1,7 @@
> >  // SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
> >  /* Copyright 2014-2016 Freescale Semiconductor Inc.
> >   * Copyright 2016 NXP
> > + * Copyright 2020 NXP
> >   */
> >
> >  #include <linux/net_tstamp.h>
> > @@ -770,7 +771,8 @@ static int dpaa2_eth_get_ts_info(struct
> > net_device *dev,
> >  	info->phc_index = dpaa2_phc_index;
> >
> >  	info->tx_types = (1 << HWTSTAMP_TX_OFF) |
> > -			 (1 << HWTSTAMP_TX_ON);
> > +			 (1 << HWTSTAMP_TX_ON) |
> > +			 (1 << HWTSTAMP_TX_ONESTEP_SYNC);
> >
> >  	info->rx_filters = (1 << HWTSTAMP_FILTER_NONE) |
> >  			   (1 << HWTSTAMP_FILTER_ALL);

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