From 652ef42c134da1bbb03bd4c9b4291dfaf8d7febb Mon Sep 17 00:00:00 2001 From: Antoine Tenart Date: Thu, 20 Sep 2018 12:08:54 +0200 Subject: [PATCH] net: mscc: fix the frame extraction into the skb When extracting frames from the Ocelot switch, the frame check sequence (FCS) is present at the end of the data extracted. The FCS was put into the sk buffer which introduced some issues (as length related ones), as the FCS shouldn't be part of an Rx sk buffer. This patch fixes the Ocelot switch extraction behaviour by discarding the FCS. Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support") Signed-off-by: Antoine Tenart Signed-off-by: David S. Miller --- drivers/net/ethernet/mscc/ocelot_board.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/mscc/ocelot_board.c b/drivers/net/ethernet/mscc/ocelot_board.c index 26bb3b18f3be..3cdf63e35b53 100644 --- a/drivers/net/ethernet/mscc/ocelot_board.c +++ b/drivers/net/ethernet/mscc/ocelot_board.c @@ -91,7 +91,7 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg) struct sk_buff *skb; struct net_device *dev; u32 *buf; - int sz, len; + int sz, len, buf_len; u32 ifh[4]; u32 val; struct frame_info info; @@ -116,14 +116,20 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg) err = -ENOMEM; break; } - buf = (u32 *)skb_put(skb, info.len); + buf_len = info.len - ETH_FCS_LEN; + buf = (u32 *)skb_put(skb, buf_len); len = 0; do { sz = ocelot_rx_frame_word(ocelot, grp, false, &val); *buf++ = val; len += sz; - } while ((sz == 4) && (len < info.len)); + } while (len < buf_len); + + /* Read the FCS and discard it */ + sz = ocelot_rx_frame_word(ocelot, grp, false, &val); + /* Update the statistics if part of the FCS was read before */ + len -= ETH_FCS_LEN - sz; if (sz < 0) { err = sz; -- 2.45.2