Commit 2244d07b authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by David S. Miller
Browse files

net: simplify flags for tx timestamping 

This patch removes the abstraction introduced by the union skb_shared_tx in
the shared skb data.

The access of the different union elements at several places led to some
confusion about accessing the shared tx_flags e.g. in skb_orphan_try().

    http://marc.info/?l=linux-netdev&m=128084897415886&w=2



Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4d5870ec

Documentation/networking/timestamping.txt

+13 −9
Original line number Diff line number Diff line
@@ -172,15 +172,19 @@ struct skb_shared_hwtstamps { 
};



Time stamps for outgoing packets are to be generated as follows:

- In hard_start_xmit(), check if skb_tx(skb)->hardware is set no-zero.

  If yes, then the driver is expected to do hardware time stamping.

- In hard_start_xmit(), check if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)

  is set no-zero. If yes, then the driver is expected to do hardware time

  stamping.

- If this is possible for the skb and requested, then declare

  that the driver is doing the time stamping by setting the field

  skb_tx(skb)->in_progress non-zero. You might want to keep a pointer

  to the associated skb for the next step and not free the skb. A driver

  not supporting hardware time stamping doesn't do that. A driver must

  never touch sk_buff::tstamp! It is used to store software generated

  time stamps by the network subsystem.

  that the driver is doing the time stamping by setting the flag

  SKBTX_IN_PROGRESS in skb_shinfo(skb)->tx_flags , e.g. with



      skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;



  You might want to keep a pointer to the associated skb for the next step

  and not free the skb. A driver not supporting hardware time stamping doesn't

  do that. A driver must never touch sk_buff::tstamp! It is used to store

  software generated time stamps by the network subsystem.

- As soon as the driver has sent the packet and/or obtained a

  hardware time stamp for it, it passes the time stamp back by

  calling skb_hwtstamp_tx() with the original skb, the raw
@@ -191,6 +195,6 @@ Time stamps for outgoing packets are to be generated as follows: 
  this would occur at a later time in the processing pipeline than other

  software time stamping and therefore could lead to unexpected deltas

  between time stamps.

- If the driver did not call set skb_tx(skb)->in_progress, then

- If the driver did not set the SKBTX_IN_PROGRESS flag (see above), then

  dev_hard_start_xmit() checks whether software time stamping

  is wanted as fallback and potentially generates the time stamp.

drivers/net/bfin_mac.c

+4 −6
Original line number Diff line number Diff line
@@ -803,15 +803,14 @@ static void bfin_dump_hwtamp(char *s, ktime_t *hw, ktime_t *ts, struct timecompa 
static void bfin_tx_hwtstamp(struct net_device *netdev, struct sk_buff *skb)

{

	struct bfin_mac_local *lp = netdev_priv(netdev);

	union skb_shared_tx *shtx = skb_tx(skb);



	if (shtx->hardware) {

	if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {

		int timeout_cnt = MAX_TIMEOUT_CNT;



		/* When doing time stamping, keep the connection to the socket

		 * a while longer

		 */

		shtx->in_progress = 1;

		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;



		/*

		 * The timestamping is done at the EMAC module's MII/RMII interface
@@ -991,7 +990,6 @@ static int bfin_mac_hard_start_xmit(struct sk_buff *skb, 
	struct bfin_mac_local *lp = netdev_priv(dev);

	u16 *data;

	u32 data_align = (unsigned long)(skb->data) & 0x3;

	union skb_shared_tx *shtx = skb_tx(skb);



	current_tx_ptr->skb = skb;
@@ -1005,7 +1003,7 @@ static int bfin_mac_hard_start_xmit(struct sk_buff *skb, 
		 * of this field are the length of the packet payload in bytes and the higher

		 * 4 bits are the timestamping enable field.

		 */

		if (shtx->hardware)

		if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)

			*data |= 0x1000;



		current_tx_ptr->desc_a.start_addr = (u32)data;
@@ -1015,7 +1013,7 @@ static int bfin_mac_hard_start_xmit(struct sk_buff *skb, 
	} else {

		*((u16 *)(current_tx_ptr->packet)) = (u16)(skb->len);

		/* enable timestamping for the sent packet */

		if (shtx->hardware)

		if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)

			*((u16 *)(current_tx_ptr->packet)) |= 0x1000;

		memcpy((u8 *)(current_tx_ptr->packet + 2), skb->data,

			skb->len);

drivers/net/gianfar.c

+6 −9
Original line number Diff line number Diff line
@@ -2048,7 +2048,6 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	u32 bufaddr;

	unsigned long flags;

	unsigned int nr_frags, nr_txbds, length;

	union skb_shared_tx *shtx;



	/*

	 * TOE=1 frames larger than 2500 bytes may see excess delays
@@ -2069,10 +2068,10 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	txq = netdev_get_tx_queue(dev, rq);

	base = tx_queue->tx_bd_base;

	regs = tx_queue->grp->regs;

	shtx = skb_tx(skb);



	/* check if time stamp should be generated */

	if (unlikely(shtx->hardware && priv->hwts_tx_en))

	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&

		     priv->hwts_tx_en))

		do_tstamp = 1;



	/* make space for additional header when fcb is needed */
@@ -2174,7 +2173,7 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev) 


	/* Setup tx hardware time stamping if requested */

	if (unlikely(do_tstamp)) {

		shtx->in_progress = 1;

		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;

		if (fcb == NULL)

			fcb = gfar_add_fcb(skb);

		fcb->ptp = 1;
@@ -2446,7 +2445,6 @@ static int gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue) 
	int howmany = 0;

	u32 lstatus;

	size_t buflen;

	union skb_shared_tx *shtx;



	rx_queue = priv->rx_queue[tx_queue->qindex];

	bdp = tx_queue->dirty_tx;
@@ -2461,8 +2459,7 @@ static int gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue) 
		 * When time stamping, one additional TxBD must be freed.

		 * Also, we need to dma_unmap_single() the TxPAL.

		 */

		shtx = skb_tx(skb);

		if (unlikely(shtx->in_progress))

		if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))

			nr_txbds = frags + 2;

		else

			nr_txbds = frags + 1;
@@ -2476,7 +2473,7 @@ static int gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue) 
				(lstatus & BD_LENGTH_MASK))

			break;



		if (unlikely(shtx->in_progress)) {

		if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)) {

			next = next_txbd(bdp, base, tx_ring_size);

			buflen = next->length + GMAC_FCB_LEN;

		} else
@@ -2485,7 +2482,7 @@ static int gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue) 
		dma_unmap_single(&priv->ofdev->dev, bdp->bufPtr,

				buflen, DMA_TO_DEVICE);



		if (unlikely(shtx->in_progress)) {

		if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)) {

			struct skb_shared_hwtstamps shhwtstamps;

			u64 *ns = (u64*) (((u32)skb->data + 0x10) & ~0x7);

			memset(&shhwtstamps, 0, sizeof(shhwtstamps));

drivers/net/igb/igb.h

+1 −1
Original line number Diff line number Diff line
@@ -143,7 +143,7 @@ struct igb_buffer { 
			u16 next_to_watch;

			unsigned int bytecount;

			u16 gso_segs;

			union skb_shared_tx shtx;

			u8 tx_flags;

			u8 mapped_as_page;

		};

		/* RX */

drivers/net/igb/igb_main.c

+5 −6
Original line number Diff line number Diff line
@@ -3954,7 +3954,7 @@ static inline int igb_tx_map_adv(struct igb_ring *tx_ring, struct sk_buff *skb, 
	}



	tx_ring->buffer_info[i].skb = skb;

	tx_ring->buffer_info[i].shtx = skb_shinfo(skb)->tx_flags;

	tx_ring->buffer_info[i].tx_flags = skb_shinfo(skb)->tx_flags;

	/* multiply data chunks by size of headers */

	tx_ring->buffer_info[i].bytecount = ((gso_segs - 1) * hlen) + skb->len;

	tx_ring->buffer_info[i].gso_segs = gso_segs;
@@ -4088,7 +4088,6 @@ netdev_tx_t igb_xmit_frame_ring_adv(struct sk_buff *skb, 
	u32 tx_flags = 0;

	u16 first;

	u8 hdr_len = 0;

	union skb_shared_tx *shtx = skb_tx(skb);



	/* need: 1 descriptor per page,

	 *       + 2 desc gap to keep tail from touching head,
@@ -4100,8 +4099,8 @@ netdev_tx_t igb_xmit_frame_ring_adv(struct sk_buff *skb, 
		return NETDEV_TX_BUSY;

	}



	if (unlikely(shtx->hardware)) {

		shtx->in_progress = 1;

	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {

		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;

		tx_flags |= IGB_TX_FLAGS_TSTAMP;

	}
@@ -5319,7 +5318,7 @@ static void igb_tx_hwtstamp(struct igb_q_vector *q_vector, struct igb_buffer *bu 
	u64 regval;



	/* if skb does not support hw timestamp or TX stamp not valid exit */

	if (likely(!buffer_info->shtx.hardware) ||

	if (likely(!(buffer_info->tx_flags & SKBTX_HW_TSTAMP)) ||

	    !(rd32(E1000_TSYNCTXCTL) & E1000_TSYNCTXCTL_VALID))

		return;
@@ -5500,7 +5499,7 @@ static void igb_rx_hwtstamp(struct igb_q_vector *q_vector, u32 staterr, 
	 * values must belong to this one here and therefore we don't need to

	 * compare any of the additional attributes stored for it.

	 *

	 * If nothing went wrong, then it should have a skb_shared_tx that we

	 * If nothing went wrong, then it should have a shared tx_flags that we

	 * can turn into a skb_shared_hwtstamps.

	 */

	if (staterr & E1000_RXDADV_STAT_TSIP) {

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