Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fc4ac67b authored by Alexander Duyck's avatar Alexander Duyck Committed by Jeff Kirsher
Browse files

i40e: Do not directly increment Tx next_to_use 



Avoid directly incrementing next_to_use for multiple reasons.  The main
reason being that if we directly increment it then it can attain a state
where it is equal to the ring count.  Technically this is a state it
should not be able to reach but the way this is written it now can.

This patch pulls the value off into a register and then increments it
and writes back either the value or 0 depending on if the value is equal
to the ring count.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarJesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: default avatarKavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 35a1e2ad

drivers/net/ethernet/intel/i40e/i40e_txrx.c

+25 −21
Original line number Diff line number Diff line
@@ -73,11 +73,12 @@ int i40e_program_fdir_filter(struct i40e_fdir_data *fdir_data, 
		goto dma_fail;



	/* grab the next descriptor */

	fdir_desc = I40E_TX_FDIRDESC(tx_ring, tx_ring->next_to_use);

	tx_buf = &tx_ring->tx_bi[tx_ring->next_to_use];

	tx_ring->next_to_use++;

	if (tx_ring->next_to_use == tx_ring->count)

		tx_ring->next_to_use = 0;

	i = tx_ring->next_to_use;

	fdir_desc = I40E_TX_FDIRDESC(tx_ring, i);

	tx_buf = &tx_ring->tx_bi[i];



	i++;

	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;



	fdir_desc->qindex_flex_ptype_vsi = cpu_to_le32((fdir_data->q_index

					     << I40E_TXD_FLTR_QW0_QINDEX_SHIFT)
@@ -134,11 +135,11 @@ int i40e_program_fdir_filter(struct i40e_fdir_data *fdir_data, 
	fdir_desc->fd_id = cpu_to_le32(fdir_data->fd_id);



	/* Now program a dummy descriptor */

	tx_desc = I40E_TX_DESC(tx_ring, tx_ring->next_to_use);

	tx_buf = &tx_ring->tx_bi[tx_ring->next_to_use];

	tx_ring->next_to_use++;

	if (tx_ring->next_to_use == tx_ring->count)

		tx_ring->next_to_use = 0;

	i = tx_ring->next_to_use;

	tx_desc = I40E_TX_DESC(tx_ring, i);



	i++;

	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;



	tx_desc->buffer_addr = cpu_to_le64(dma);

	td_cmd = I40E_TX_DESC_CMD_EOP |
@@ -148,9 +149,6 @@ int i40e_program_fdir_filter(struct i40e_fdir_data *fdir_data, 
	tx_desc->cmd_type_offset_bsz =

		build_ctob(td_cmd, 0, I40E_FDIR_MAX_RAW_PACKET_LOOKUP, 0);



	/* Mark the data descriptor to be watched */

	tx_buf->next_to_watch = tx_desc;



	/* Force memory writes to complete before letting h/w

	 * know there are new descriptors to fetch.  (Only

	 * applicable for weak-ordered memory model archs,
@@ -158,6 +156,9 @@ int i40e_program_fdir_filter(struct i40e_fdir_data *fdir_data, 
	 */

	wmb();



	/* Mark the data descriptor to be watched */

	tx_buf->next_to_watch = tx_desc;



	writel(tx_ring->next_to_use, tx_ring->tail);

	return 0;
@@ -1143,6 +1144,7 @@ static void i40e_atr(struct i40e_ring *tx_ring, struct sk_buff *skb, 
	struct tcphdr *th;

	unsigned int hlen;

	u32 flex_ptype, dtype_cmd;

	u16 i;



	/* make sure ATR is enabled */

	if (!(pf->flags & I40E_FLAG_FDIR_ATR_ENABLED))
@@ -1182,10 +1184,11 @@ static void i40e_atr(struct i40e_ring *tx_ring, struct sk_buff *skb, 
	tx_ring->atr_count = 0;



	/* grab the next descriptor */

	fdir_desc = I40E_TX_FDIRDESC(tx_ring, tx_ring->next_to_use);

	tx_ring->next_to_use++;

	if (tx_ring->next_to_use == tx_ring->count)

		tx_ring->next_to_use = 0;

	i = tx_ring->next_to_use;

	fdir_desc = I40E_TX_FDIRDESC(tx_ring, i);



	i++;

	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;



	flex_ptype = (tx_ring->queue_index << I40E_TXD_FLTR_QW0_QINDEX_SHIFT) &

		      I40E_TXD_FLTR_QW0_QINDEX_MASK;
@@ -1481,15 +1484,16 @@ static void i40e_create_tx_ctx(struct i40e_ring *tx_ring, 
			       const u32 cd_tunneling, const u32 cd_l2tag2)

{

	struct i40e_tx_context_desc *context_desc;

	int i = tx_ring->next_to_use;



	if (!cd_type_cmd_tso_mss && !cd_tunneling && !cd_l2tag2)

		return;



	/* grab the next descriptor */

	context_desc = I40E_TX_CTXTDESC(tx_ring, tx_ring->next_to_use);

	tx_ring->next_to_use++;

	if (tx_ring->next_to_use == tx_ring->count)

		tx_ring->next_to_use = 0;

	context_desc = I40E_TX_CTXTDESC(tx_ring, i);



	i++;

	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;



	/* cpu_to_le32 and assign to struct fields */

	context_desc->tunneling_params = cpu_to_le32(cd_tunneling);