When picking the buffsize to use based on the MTU, we shouldn't check only the MTU value, but also : - ETH_HLEN for the L2 header, - up to 2 VLAN tags, - the FCS, - the NET_IP_ALIGN The default bufsize is 1536 bytes, which is enough to contain all the above so this hasn't surfaced before, but the addition of NET_IP_ALIGN to the start of buffer address tripped the Jumbo selftest, leading to this discovery. With that, we don't need the '>=' checks on the buffer len, we can use more consistent comparison operators in stmmac_set_bfsize. Fixes: 286a83721720 ("stmmac: add CHAINED descriptor mode support (V4)") Reviewed-by: Nicolai Buchwitz Signed-off-by: Maxime Chevallier --- .../net/ethernet/stmicro/stmmac/stmmac_main.c | 20 ++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 62c3441911e7..29b970574a38 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -1536,17 +1536,17 @@ static unsigned int stmmac_rx_offset(struct stmmac_priv *priv) return NET_SKB_PAD + NET_IP_ALIGN; } -static int stmmac_set_bfsize(int mtu) +static int stmmac_set_bfsize(int len) { int ret; - if (mtu >= BUF_SIZE_8KiB) + if (len > BUF_SIZE_8KiB) ret = BUF_SIZE_16KiB; - else if (mtu >= BUF_SIZE_4KiB) + else if (len > BUF_SIZE_4KiB) ret = BUF_SIZE_8KiB; - else if (mtu >= BUF_SIZE_2KiB) + else if (len > BUF_SIZE_2KiB) ret = BUF_SIZE_4KiB; - else if (mtu > DEFAULT_BUFSIZE) + else if (len > DEFAULT_BUFSIZE) ret = BUF_SIZE_2KiB; else ret = DEFAULT_BUFSIZE; @@ -4063,7 +4063,7 @@ static struct stmmac_dma_conf * stmmac_setup_dma_desc(struct stmmac_priv *priv, unsigned int mtu) { struct stmmac_dma_conf *dma_conf; - int bfsize, ret; + int bfsize, len, ret; u8 chan; dma_conf = kzalloc_obj(*dma_conf); @@ -4073,13 +4073,15 @@ stmmac_setup_dma_desc(struct stmmac_priv *priv, unsigned int mtu) return ERR_PTR(-ENOMEM); } - /* Returns 0 or BUF_SIZE_16KiB if mtu > 8KiB and dwmac4 or ring mode */ - bfsize = stmmac_set_16kib_bfsize(priv, mtu); + len = mtu + ETH_HLEN + 2 * VLAN_HLEN + ETH_FCS_LEN + NET_IP_ALIGN; + + /* Returns 0 or BUF_SIZE_16KiB if len > 8KiB and dwmac4 or ring mode */ + bfsize = stmmac_set_16kib_bfsize(priv, len); if (bfsize < 0) bfsize = 0; if (bfsize < BUF_SIZE_16KiB) - bfsize = stmmac_set_bfsize(mtu); + bfsize = stmmac_set_bfsize(len); dma_conf->dma_buf_sz = bfsize; /* Chose the tx/rx size from the already defined one in the -- 2.55.0