netdev - [PATCH net 2/2] qede: fix memory allocation failures under heavy load

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Date:   Tue, 16 Mar 2021 11:34:10 -0700
From:   Bhaskar Upadhaya <bupadhaya@...vell.com>
To:     <netdev@...r.kernel.org>, <kuba@...nel.org>, <aelior@...vell.com>,
        <irusskikh@...vell.com>
CC:     <davem@...emloft.net>, <bupadhaya@...vell.com>
Subject: [PATCH net 2/2] qede: fix memory allocation failures under heavy load

when the system is heavily stressed, kernel get lots of memory
allocation failures which causes kernel panic, so enable proper
error handling during skb allocation

Fixes: 8a8633978b84 ("qede: Add build_skb() support.")
Signed-off-by: Bhaskar Upadhaya <bupadhaya@...vell.com>
Signed-off-by: Igor Russkikh <irusskikh@...vell.com>
Signed-off-by: Ariel Elior <aelior@...vell.com>
---
 drivers/net/ethernet/qlogic/qede/qede_fp.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c
index 8c47a9d2a965..f2d74b53e421 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_fp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c
@@ -751,6 +751,8 @@ qede_build_skb(struct qede_rx_queue *rxq,
 
 	buf = page_address(bd->data) + bd->page_offset;
 	skb = build_skb(buf, rxq->rx_buf_seg_size);
+	if (unlikely(!skb))
+		return NULL;
 
 	skb_reserve(skb, pad);
 	skb_put(skb, len);
@@ -767,6 +769,9 @@ qede_tpa_rx_build_skb(struct qede_dev *edev,
 	struct sk_buff *skb;
 
 	skb = qede_build_skb(rxq, bd, len, pad);
+	if (unlikely(!skb))
+		return NULL;
+
 	bd->page_offset += rxq->rx_buf_seg_size;
 
 	if (bd->page_offset == PAGE_SIZE) {
@@ -814,6 +819,8 @@ qede_rx_build_skb(struct qede_dev *edev,
 	}
 
 	skb = qede_build_skb(rxq, bd, len, pad);
+	if (unlikely(!skb))
+		return NULL;
 
 	if (unlikely(qede_realloc_rx_buffer(rxq, bd))) {
 		/* Incr page ref count to reuse on allocation failure so
@@ -851,11 +858,16 @@ static void qede_tpa_start(struct qede_dev *edev,
 	if (unlikely(!tpa_info->skb)) {
 		DP_NOTICE(edev, "Failed to allocate SKB for gro\n");
 
+		/* Re-use the buffer instantly instead doing it at tpa_end
+		 * as we are already going to throw away this aggregated packet
+		 * (i.e CQEs till tpa_end) and then going to update the
+		 * producer, so it's safe to pin the buffer here only.
+		 */
+		qede_reuse_page(rxq, sw_rx_data_cons);
 		/* Consume from ring but do not produce since
 		 * this might be used by FW still, it will be re-used
 		 * at TPA end.
 		 */
-		tpa_info->tpa_start_fail = true;
 		qede_rx_bd_ring_consume(rxq);
 		tpa_info->state = QEDE_AGG_STATE_ERROR;
 		goto cons_buf;
@@ -1025,11 +1037,6 @@ static int qede_tpa_end(struct qede_dev *edev,
 err:
 	tpa_info->state = QEDE_AGG_STATE_NONE;
 
-	if (tpa_info->tpa_start_fail) {
-		qede_reuse_page(rxq, &tpa_info->buffer);
-		tpa_info->tpa_start_fail = false;
-	}
-
 	dev_kfree_skb_any(tpa_info->skb);
 	tpa_info->skb = NULL;
 	return 0;
-- 
2.17.1