[PATCH AUTOSEL for 4.14 33/51] staging: fsl-dpaa2/eth: Account for Rx FD buffers on error path

[alexander . levin]

From: Ioana Radulescu <ruxandra.radule...@nxp.com>

[ Upstream commit cbb3ea40fc495bf04070200b35c1c4cd05d11bd3 ]

On Rx path, if we fail to build an skb from the incoming FD,
we still need to update the channel buffer count accordingly,
otherwise we risk depleting the pool while the software counter
still sees available buffers.

Signed-off-by: Ioana Radulescu <ruxandra.radule...@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
---
 drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c 
b/drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c
index 26017fe9df93..8e84b2e7f5bd 100644
--- a/drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c
+++ b/drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c
@@ -131,6 +131,8 @@ static struct sk_buff *build_linear_skb(struct 
dpaa2_eth_priv *priv,
        u16 fd_offset = dpaa2_fd_get_offset(fd);
        u32 fd_length = dpaa2_fd_get_len(fd);
 
+       ch->buf_count--;
+
        skb = build_skb(fd_vaddr, DPAA2_ETH_RX_BUF_SIZE +
                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
        if (unlikely(!skb))
@@ -139,8 +141,6 @@ static struct sk_buff *build_linear_skb(struct 
dpaa2_eth_priv *priv,
        skb_reserve(skb, fd_offset);
        skb_put(skb, fd_length);
 
-       ch->buf_count--;
-
        return skb;
 }
 
@@ -178,8 +178,15 @@ static struct sk_buff *build_frag_skb(struct 
dpaa2_eth_priv *priv,
                        /* We build the skb around the first data buffer */
                        skb = build_skb(sg_vaddr, DPAA2_ETH_RX_BUF_SIZE +
                                SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
-                       if (unlikely(!skb))
-                               return NULL;
+                       if (unlikely(!skb)) {
+                               /* We still need to subtract the buffers used
+                                * by this FD from our software counter
+                                */
+                               while (!dpaa2_sg_is_final(&sgt[i]) &&
+                                      i < DPAA2_ETH_MAX_SG_ENTRIES)
+                                       i++;
+                               break;
+                       }
 
                        sg_offset = dpaa2_sg_get_offset(sge);
                        skb_reserve(skb, sg_offset);
-- 
2.11.0