[PATCH net v4 5/7] net: stmmac: dwmac4: Use the correct bufzise when the len is exactly 8K
From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: 2026-09-17 21:54:39
Also in:
linux-arm-kernel, lkml
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Chevallier, Linus Torvalds
DMA bufsize selection isn't made on the MTU but the actual frame length,
so including the L2 header. On DWMAC4, if the len is exactly BUF_SIZE_8KiB,
the next larger size is incorrectly selected.
Lets fix the comparison and while at it, rename the parameter from len
to mtu.
Fixes: c3efed5ad1b0 ("net: stmmac: Enable dwmac4 jumbo frame more than 8KiB").
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c | 4 ++--
drivers/net/ethernet/stmicro/stmmac/hwif.h | 2 +-
drivers/net/ethernet/stmicro/stmmac/ring_mode.c | 4 ++--
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
index 2994df41ec2c..c6a8f8d73501 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c@@ -474,11 +474,11 @@ static void dwmac4_set_sarc(struct dma_desc *p, u32 sarc_type) sarc_type)); } -static int set_16kib_bfsize(int mtu) +static int set_16kib_bfsize(int len) { int ret = 0; - if (unlikely(mtu >= BUF_SIZE_8KiB)) + if (unlikely(len > BUF_SIZE_8KiB)) ret = BUF_SIZE_16KiB; return ret; }
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index 04dafec021b4..de7aa6d28148 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h@@ -540,7 +540,7 @@ struct stmmac_mode_ops { bool (*is_jumbo_frm)(unsigned int len, bool enh_desc); int (*jumbo_frm)(struct stmmac_tx_queue *tx_q, struct sk_buff *skb, int csum); - int (*set_16kib_bfsize)(int mtu); + int (*set_16kib_bfsize)(int len); void (*init_desc3)(struct dma_desc *p); void (*refill_desc3)(struct stmmac_rx_queue *rx_q, struct dma_desc *p); void (*clean_desc3)(struct stmmac_tx_queue *tx_q, struct dma_desc *p);
diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
index f7949419eb9f..d2f0c321661d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c@@ -124,10 +124,10 @@ static void clean_desc3(struct stmmac_tx_queue *tx_q, struct dma_desc *p) p->des3 = 0; } -static int set_16kib_bfsize(int mtu) +static int set_16kib_bfsize(int len) { int ret = 0; - if (unlikely(mtu > BUF_SIZE_8KiB)) + if (unlikely(len > BUF_SIZE_8KiB)) ret = BUF_SIZE_16KiB; return ret; }
--
2.55.0