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From: Thierry Herbelot <thierry.herbelot@6wind.com>
To: dev@dpdk.org
Cc: Olivier Matz <olivier.matz@6wind.com>,
	stable@dpdk.org, Thomas Monjalon <thomas@monjalon.net>
Subject: [dpdk-stable] [PATCH 19.11 V3 05/12] net/ixgbe: fix Tx descriptor status api
Date: Thu,  8 Aug 2019 10:22:10 +0200
Message-ID: <f48d1da56cba439783ffd9372c603cccd1135d49.1565252336.git.thierry.herbelot@6wind.com> (raw)
In-Reply-To: <cover.1565190405.git.thierry.herbelot@6wind.com>

From: Olivier Matz <olivier.matz@6wind.com>

The Tx descriptor status api was not behaving as expected. This API is
used to inspect the content of the descriptors in the Tx ring to
determine the length of the Tx queue.

Since the software advances the tail pointer and the hardware advances
the head pointer, the Tx queue is located before txq->tx_tail in the
ring. Therefore, a call to rte_eth_tx_descriptor_status(..., offset=20)
should inspect the 20th descriptor before the tail, not after.

As before, we still need to take care about only checking descriptors
that have the RS bit.

Additionally, we can avoid an access to the ring if offset is greater or
equal to nb_tx_desc - nb_tx_free.

Fixes: 5da8b8814178 ("net/ixgbe: implement descriptor status API")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 drivers/net/ixgbe/ixgbe_rxtx.c | 45 +++++++++++++++++++++++++++++++-----------
 drivers/net/ixgbe/ixgbe_rxtx.h |  1 +
 2 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index edcfa60cec98..4abc2fe37488 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -2627,10 +2627,15 @@ ixgbe_dev_tx_queue_setup(struct rte_eth_dev *dev,
 	    hw->mac.type == ixgbe_mac_X540_vf ||
 	    hw->mac.type == ixgbe_mac_X550_vf ||
 	    hw->mac.type == ixgbe_mac_X550EM_x_vf ||
-	    hw->mac.type == ixgbe_mac_X550EM_a_vf)
+	    hw->mac.type == ixgbe_mac_X550EM_a_vf) {
 		txq->tdt_reg_addr = IXGBE_PCI_REG_ADDR(hw, IXGBE_VFTDT(queue_idx));
-	else
+		txq->tdh_reg_addr = IXGBE_PCI_REG_ADDR(hw,
+						       IXGBE_VFTDH(queue_idx));
+	} else {
 		txq->tdt_reg_addr = IXGBE_PCI_REG_ADDR(hw, IXGBE_TDT(txq->reg_idx));
+		txq->tdh_reg_addr = IXGBE_PCI_REG_ADDR(hw,
+						       IXGBE_TDH(txq->reg_idx));
+	}
 
 	txq->tx_ring_phys_addr = tz->iova;
 	txq->tx_ring = (union ixgbe_adv_tx_desc *) tz->addr;
@@ -3163,22 +3168,38 @@ ixgbe_dev_tx_descriptor_status(void *tx_queue, uint16_t offset)
 {
 	struct ixgbe_tx_queue *txq = tx_queue;
 	volatile uint32_t *status;
-	uint32_t desc;
+	int32_t desc, dd;
 
 	if (unlikely(offset >= txq->nb_tx_desc))
 		return -EINVAL;
+	if (offset >= txq->nb_tx_desc - txq->nb_tx_free)
+		return RTE_ETH_TX_DESC_DONE;
+
+	desc = txq->tx_tail - offset - 1;
+	if (desc < 0)
+		desc += txq->nb_tx_desc;
 
-	desc = txq->tx_tail + offset;
-	/* go to next desc that has the RS bit */
-	desc = ((desc + txq->tx_rs_thresh - 1) / txq->tx_rs_thresh) *
-		txq->tx_rs_thresh;
-	if (desc >= txq->nb_tx_desc) {
-		desc -= txq->nb_tx_desc;
-		if (desc >= txq->nb_tx_desc)
-			desc -= txq->nb_tx_desc;
+	/* offset is too small, no other way than reading PCI reg */
+	if (unlikely(offset < txq->tx_rs_thresh)) {
+		int16_t tx_head, queue_size;
+		tx_head = ixgbe_read_addr(txq->tdh_reg_addr);
+		queue_size = txq->tx_tail - tx_head;
+		if (queue_size < 0)
+			queue_size += txq->nb_tx_desc;
+		return queue_size > offset ? RTE_ETH_TX_DESC_FULL :
+			RTE_ETH_TX_DESC_DONE;
 	}
 
-	status = &txq->tx_ring[desc].wb.status;
+	/* index of the dd bit to look at */
+	dd = (desc / txq->tx_rs_thresh + 1) * txq->tx_rs_thresh - 1;
+
+	/* In full featured mode, RS bit is only set in the last descriptor */
+	/* of a multisegments packet */
+	if (!(txq->offloads == 0 &&
+	      txq->tx_rs_thresh >= RTE_PMD_IXGBE_TX_MAX_BURST))
+		dd = txq->sw_ring[dd].last_id;
+
+	status = &txq->tx_ring[dd].wb.status;
 	if (*status & rte_cpu_to_le_32(IXGBE_ADVTXD_STAT_DD))
 		return RTE_ETH_TX_DESC_DONE;
 
diff --git a/drivers/net/ixgbe/ixgbe_rxtx.h b/drivers/net/ixgbe/ixgbe_rxtx.h
index 505d344b9cee..05fd4167576c 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.h
+++ b/drivers/net/ixgbe/ixgbe_rxtx.h
@@ -201,6 +201,7 @@ struct ixgbe_tx_queue {
 		struct ixgbe_tx_entry_v *sw_ring_v; /**< address of SW ring for vector PMD */
 	};
 	volatile uint32_t   *tdt_reg_addr; /**< Address of TDT register. */
+	volatile uint32_t   *tdh_reg_addr; /**< Address of TDH register. */
 	uint16_t            nb_tx_desc;    /**< number of TX descriptors. */
 	uint16_t            tx_tail;       /**< current value of TDT reg. */
 	/**< Start freeing TX buffers if there are less free descriptors than
-- 
2.11.0


  parent reply index

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-07 14:37 [dpdk-stable] [PATCH 19.11 00/12] Miscellaneous fixes Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 01/12] net/ixgbevf: fix stats update after a PF reset Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 02/12] ethdev: fix description of tx descriptor status Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 03/12] net/e1000: fix Tx descriptor status api (igb) Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 04/12] net/e1000: fix Tx descriptor status api (em) Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 05/12] net/ixgbe: fix Tx descriptor status api Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 06/12] net/i40e: " Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 07/12] net/i40e: set speed to undefined for default case in link update Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 08/12] virtio: fix rx stats with vectorized functions Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 09/12] virtio: get all pending rx packets " Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 10/12] drivers/crypto/openssl: use a local copy for the session contexts Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 11/12] drivers/crypto/dpaa_sec: update DPAA iova table in dpaa_mem_vtop Thierry Herbelot
2019-08-07 14:37 ` [dpdk-stable] [PATCH 19.11 12/12] drivers/crypto/octeontx: enable unbinding for the OcteonTx crypto engines Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 00/12] Miscellaneous fixes Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 " Thierry Herbelot
2019-08-08 13:19     ` Thierry Herbelot
2019-08-08 14:34       ` Thomas Monjalon
2019-10-10 13:01         ` [dpdk-stable] [dpdk-dev] " David Marchand
2019-10-10 13:12           ` Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 01/12] net/ixgbevf: fix stats update after a PF reset Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 02/12] ethdev: fix description of tx descriptor status Thierry Herbelot
2019-08-08 10:37     ` [dpdk-stable] [dpdk-dev] " Andrew Rybchenko
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 03/12] net/e1000: fix Tx descriptor status api (igb) Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 04/12] net/e1000: fix Tx descriptor status api (em) Thierry Herbelot
2019-08-08  8:22   ` Thierry Herbelot [this message]
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 06/12] net/i40e: fix Tx descriptor status api Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 07/12] net/i40e: set speed to undefined for default case in link update Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 08/12] virtio: fix rx stats with vectorized functions Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 09/12] virtio: get all pending rx packets " Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 10/12] drivers/crypto/openssl: use a local copy for the session contexts Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 11/12] drivers/crypto/dpaa_sec: update DPAA iova table in dpaa_mem_vtop Thierry Herbelot
2019-08-08  8:22   ` [dpdk-stable] [PATCH 19.11 V3 12/12] drivers/crypto/octeontx: enable unbinding for the OcteonTx crypto engines Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 01/12] net/ixgbevf: fix stats update after a PF reset Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 02/12] ethdev: fix description of tx descriptor status Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 03/12] net/e1000: fix Tx descriptor status api (igb) Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 04/12] net/e1000: fix Tx descriptor status api (em) Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 05/12] net/ixgbe: fix Tx descriptor status api Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 06/12] net/i40e: " Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 07/12] net/i40e: set speed to undefined for default case in link update Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 08/12] virtio: fix rx stats with vectorized functions Thierry Herbelot
2019-08-08  5:15   ` Tiwei Bie
2019-08-08  7:35     ` Thibaut Collet
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 09/12] virtio: get all pending rx packets " Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 10/12] drivers/crypto/openssl: use a local copy for the session contexts Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 11/12] drivers/crypto/dpaa_sec: update DPAA iova table in dpaa_mem_vtop Thierry Herbelot
2019-08-07 15:09 ` [dpdk-stable] [PATCH 19.11 V2 12/12] drivers/crypto/octeontx: enable unbinding for the OcteonTx crypto engines Thierry Herbelot

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