[3.19.y-ckt stable] Patch "net: mvpp2: fix refilling BM pools in RX path" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    net: mvpp2: fix refilling BM pools in RX path

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt13.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 33076bad5dd8d1f0b4b42e2427dd6ff6a799d3bf Mon Sep 17 00:00:00 2001
From: Marcin Wojtas <mw at semihalf.com>
Date: Thu, 3 Dec 2015 15:20:51 +0100
Subject: net: mvpp2: fix refilling BM pools in RX path

commit b5015854674b653d982f104936ec688e253469b9 upstream.

In hitherto code in case of RX buffer allocation error during refill,
original buffer is pushed to the network stack, but the amount of
available buffer pointers in BM pool is decreased.

This commit fixes the situation by moving refill call before skb_put(),
and returning original buffer pointer to the pool in case of an error.

Signed-off-by: Marcin Wojtas <mw at semihalf.com>

Fixes: 3f518509dedc ("ethernet: Add new driver for Marvell Armada 375
network unit")

Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/ethernet/marvell/mvpp2.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2.c b/drivers/net/ethernet/marvell/mvpp2.c
index a18d4e4..0113ac0 100644
--- a/drivers/net/ethernet/marvell/mvpp2.c
+++ b/drivers/net/ethernet/marvell/mvpp2.c
@@ -5031,7 +5031,8 @@ static int mvpp2_rx(struct mvpp2_port *port, int rx_todo,
 		    struct mvpp2_rx_queue *rxq)
 {
 	struct net_device *dev = port->dev;
-	int rx_received, rx_filled, i;
+	int rx_received;
+	int rx_done = 0;
 	u32 rcvd_pkts = 0;
 	u32 rcvd_bytes = 0;

@@ -5040,17 +5041,18 @@ static int mvpp2_rx(struct mvpp2_port *port, int rx_todo,
 	if (rx_todo > rx_received)
 		rx_todo = rx_received;

-	rx_filled = 0;
-	for (i = 0; i < rx_todo; i++) {
+	while (rx_done < rx_todo) {
 		struct mvpp2_rx_desc *rx_desc = mvpp2_rxq_next_desc_get(rxq);
 		struct mvpp2_bm_pool *bm_pool;
 		struct sk_buff *skb;
+		dma_addr_t phys_addr;
 		u32 bm, rx_status;
 		int pool, rx_bytes, err;

-		rx_filled++;
+		rx_done++;
 		rx_status = rx_desc->status;
 		rx_bytes = rx_desc->data_size - MVPP2_MH_SIZE;
+		phys_addr = rx_desc->buf_phys_addr;

 		bm = mvpp2_bm_cookie_build(rx_desc);
 		pool = mvpp2_bm_cookie_pool_get(bm);
@@ -5067,8 +5069,10 @@ static int mvpp2_rx(struct mvpp2_port *port, int rx_todo,
 		 * comprised by the RX descriptor.
 		 */
 		if (rx_status & MVPP2_RXD_ERR_SUMMARY) {
+		err_drop_frame:
 			dev->stats.rx_errors++;
 			mvpp2_rx_error(port, rx_desc);
+			/* Return the buffer to the pool */
 			mvpp2_pool_refill(port, bm, rx_desc->buf_phys_addr,
 					  rx_desc->buf_cookie);
 			continue;
@@ -5076,7 +5080,13 @@ static int mvpp2_rx(struct mvpp2_port *port, int rx_todo,

 		skb = (struct sk_buff *)rx_desc->buf_cookie;

-		dma_unmap_single(dev->dev.parent, rx_desc->buf_phys_addr,
+		err = mvpp2_rx_refill(port, bm_pool, bm, 0);
+		if (err) {
+			netdev_err(port->dev, "failed to refill BM pools\n");
+			goto err_drop_frame;
+		}
+
+		dma_unmap_single(dev->dev.parent, phys_addr,
 				 bm_pool->buf_size, DMA_FROM_DEVICE);

 		rcvd_pkts++;
@@ -5089,12 +5099,6 @@ static int mvpp2_rx(struct mvpp2_port *port, int rx_todo,
 		mvpp2_rx_csum(port, rx_status, skb);

 		napi_gro_receive(&port->napi, skb);
-
-		err = mvpp2_rx_refill(port, bm_pool, bm, 0);
-		if (err) {
-			netdev_err(port->dev, "failed to refill BM pools\n");
-			rx_filled--;
-		}
 	}

 	if (rcvd_pkts) {
@@ -5108,7 +5112,7 @@ static int mvpp2_rx(struct mvpp2_port *port, int rx_todo,

 	/* Update Rx queue management counters */
 	wmb();
-	mvpp2_rxq_status_update(port, rxq->id, rx_todo, rx_filled);
+	mvpp2_rxq_status_update(port, rxq->id, rx_done, rx_done);

 	return rx_todo;
 }
--
1.9.1