* [PATCH net-next v2 1/2] net: ethernet: cortina: Ack RX overrun interrupt correctly
2026-09-14 21:26 [PATCH net-next v2 0/2] net: ethernet: cortina: Gemini Ethernet fixes, part 2 Linus Walleij
@ 2026-09-14 21:26 ` Linus Walleij
2026-09-14 21:26 ` [PATCH net-next v2 2/2] net: ethernet: cortina: Bound RX descriptor processing Linus Walleij
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Linus Walleij @ 2026-09-14 21:26 UTC (permalink / raw)
To: Hans Ulli Kroll, Andrew Lunn, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Michał Mirosław
Cc: netdev, Linus Walleij
The RX overrun interrupt is reported in interrupt status register 4, but
gmac_irq() acknowledges it using the RX descriptor error bit from status
register 0. For GMAC0 this writes the GMAC1 overrun bit, while for GMAC1
the shift leaves no bit in the 32-bit register.
Acknowledge the same per-port RX overrun bit that was detected.
Fixes: 4d5ae32f5e1e ("net: ethernet: Add a driver for Gemini gigabit ethernet")
Assisted-by: LLM
Signed-off-by: Linus Walleij <linusw@kernel.org>
---
drivers/net/ethernet/cortina/gemini.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index f08de623e6f7..2dd2fa801829 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -1798,7 +1798,7 @@ static irqreturn_t gmac_irq(int irq, void *data)
if (val & (GMAC0_RX_OVERRUN_INT_BIT << (netdev->dev_id * 8))) {
spin_lock(&geth->irq_lock);
- writel(GMAC0_RXDERR_INT_BIT << (netdev->dev_id * 8),
+ writel(GMAC0_RX_OVERRUN_INT_BIT << (netdev->dev_id * 8),
geth->base + GLOBAL_INTERRUPT_STATUS_4_REG);
u64_stats_update_begin(&port->ir_stats_syncp);
++port->stats.rx_fifo_errors;
--
2.55.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH net-next v2 2/2] net: ethernet: cortina: Bound RX descriptor processing
2026-09-14 21:26 [PATCH net-next v2 0/2] net: ethernet: cortina: Gemini Ethernet fixes, part 2 Linus Walleij
2026-09-14 21:26 ` [PATCH net-next v2 1/2] net: ethernet: cortina: Ack RX overrun interrupt correctly Linus Walleij
@ 2026-09-14 21:26 ` Linus Walleij
2026-09-17 0:50 ` [PATCH net-next v2 0/2] net: ethernet: cortina: Gemini Ethernet fixes, part 2 patchwork-bot+netdevbpf
2026-09-17 0:50 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 5+ messages in thread
From: Linus Walleij @ 2026-09-14 21:26 UTC (permalink / raw)
To: Hans Ulli Kroll, Andrew Lunn, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Michał Mirosław
Cc: netdev, Linus Walleij
NAPI budgets received packets, so gmac_rx() only consumes budget when an
EOF descriptor completes a frame. A malformed descriptor stream without
EOF can consequently make one poll consume the entire snapshotted RX ring,
which may contain up to 32768 descriptors. The error paths can also flood
the kernel log while doing so.
Keep the packet budget EOF-based, but impose a separate descriptor limit
which allows MAX_SKB_FRAGS descriptors for every packet in the budget. If
the limit is reached with descriptors still pending, return the full NAPI
budget to retain ownership and continue in another poll. Ratelimit errors
reported from malformed descriptor paths.
Fixes: 4d5ae32f5e1e ("net: ethernet: Add a driver for Gemini gigabit ethernet")
Assisted-by: LLM
Signed-off-by: Linus Walleij <linusw@kernel.org>
---
drivers/net/ethernet/cortina/gemini.c | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 2dd2fa801829..2fe7fd0202d2 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -16,6 +16,7 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/net.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
@@ -736,7 +737,8 @@ gmac_get_queue_page(struct gemini_ethernet *geth,
mapping = addr & PAGE_MASK;
if (!geth->freeq_pages) {
- dev_err(geth->dev, "try to get page with no page list\n");
+ dev_err_ratelimited(geth->dev,
+ "try to get page with no page list\n");
return NULL;
}
@@ -1441,7 +1443,7 @@ static struct sk_buff *gmac_skb_if_good_frame(struct gemini_ethernet_port *port,
}
static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget,
- unsigned int *freeq_consumed)
+ unsigned int *freeq_consumed, bool *reschedule)
{
struct gemini_ethernet_port *port = netdev_priv(netdev);
unsigned short m = (1 << port->rxq_order) - 1;
@@ -1449,6 +1451,8 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget,
void __iomem *ptr_reg = port->rxq_rwptr;
unsigned int frag_nr = port->rx_frag_nr;
struct sk_buff *skb = port->rx_skb;
+ /* Bound malformed chains while allowing maximum fragments per frame. */
+ unsigned int desc_limit = budget * MAX_SKB_FRAGS;
unsigned int consumed = 0;
unsigned int frame_len, frag_len;
struct gmac_rxdesc *rx = NULL;
@@ -1475,7 +1479,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget,
r = rw.bits.rptr;
w = rw.bits.wptr;
- while (budget && w != r) {
+ while (budget && consumed < desc_limit && w != r) {
page = NULL;
rx = port->rxq_ring + r;
word0 = rx->word0;
@@ -1502,15 +1506,18 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget,
}
if (!mapping) {
- netdev_err(netdev,
- "rxq[%u]: HW BUG: zero DMA desc\n", r);
+ if (net_ratelimit())
+ netdev_err(netdev,
+ "rxq[%u]: HW BUG: zero DMA desc\n",
+ r);
goto err_drop;
}
/* Freeq pointers are one page off */
gpage = gmac_get_queue_page(geth, port, mapping + PAGE_SIZE);
if (!gpage) {
- dev_err(geth->dev, "could not find mapping\n");
+ dev_err_ratelimited(geth->dev,
+ "could not find mapping\n");
goto err_drop;
}
page = gpage->page;
@@ -1535,7 +1542,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget,
if (frag_nr == MAX_SKB_FRAGS)
goto err_drop;
- if (frag_len == 0)
+ if (frag_len == 0 && net_ratelimit())
netdev_err(netdev, "Received fragment with len = 0\n");
skb_fill_page_desc(skb, frag_nr, page, page_offs, frag_len);
@@ -1579,6 +1586,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget,
port->rx_frag_nr = frag_nr;
port->rx_dropping = dropping;
*freeq_consumed = consumed;
+ *reschedule = budget && w != r;
writew(r, ptr_reg);
return received;
}
@@ -1590,12 +1598,13 @@ static int gmac_napi_poll(struct napi_struct *napi, int budget)
unsigned int freeq_threshold;
unsigned int freeq_consumed;
unsigned int received;
+ bool reschedule;
freeq_threshold = 1 << (geth->freeq_order - 1);
u64_stats_update_begin(&port->rx_stats_syncp);
- received = gmac_rx(napi->dev, budget, &freeq_consumed);
- if (received < budget)
+ received = gmac_rx(napi->dev, budget, &freeq_consumed, &reschedule);
+ if (!reschedule && received < budget)
++port->rx_napi_exits;
u64_stats_update_end(&port->rx_stats_syncp);
@@ -1606,10 +1615,11 @@ static int gmac_napi_poll(struct napi_struct *napi, int budget)
geth_fill_freeq(geth, true);
}
- if (received < budget && napi_complete_done(napi, received))
+ if (!reschedule && received < budget &&
+ napi_complete_done(napi, received))
gmac_enable_rx_irq(napi->dev, 1);
- return received;
+ return reschedule ? budget : received;
}
static void gmac_dump_dma_state(struct net_device *netdev)
--
2.55.0
^ permalink raw reply related [flat|nested] 5+ messages in thread