[PATCH 4.14 45/75] staging: fsl-dpaa2/eth: Account for Rx FD buffers on error path

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ioana Radulescu <ruxandra.radulescu@xxxxxxx>


[ 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.radulescu@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

--- 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(
 	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(
 	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(st
 			/* 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);