RE: [PATCH net-next v11 3/7] r8169: add support for new interrupt mapping

From: Javen

Date: Mon Aug 17 2026 - 03:22:34 EST

>
>On 8/13/26 6:51 PM, javen wrote:
>> From: Javen Xu <javen_xu@xxxxxxxxxxxxxx>
>>
>> To support RSS, the number of hardware interrupt bits should match the
>> interrupt of software. So we add support for new interrupt mapping here.
>> ISR_VEC_MAP_REG is the hardware register to indicate interrupt status.
>> IMR_SET_VEC_MAP_REG is interrupt mask which is set to enable irq.
>>
>> Signed-off-by: Javen Xu <javen_xu@xxxxxxxxxxxxxx>
>> ---
>> Changes in v2:
>> - no changes
>>
>> Changes in v3:
>> - init index in napi_struct and get message_id from index
>> - move rtl8169_disable_hw_interrupt_msix directly before the call to
>> napi_schedule()
>> - change the condition in rtl8169_request_irq when RTL_VEC_MAP_ENABLE
>> enabled, use rtl8169_interrupt_msix
>>
>> Changes in v4:
>> - remove flag tp->feature, replace tp->features & RTL_VEC_MAP_ENABLE
>> with tp->irq_nvecs > 1, they are equivalent.
>> - follow reverse xmas tree, in rtl8169_interrupt_msix(),
>> rtl8169_poll_msix_rx(), rtl8169_poll_msix_tx(),
>> rtl8169_poll_msix_other()
>> - use napi->index in rtl8169_poll_msix_other()
>> - add a comment to describe RTL8127 MSI-X vector layout
>> - simplify r8169_init_napi()
>>
>> Changes in v5:
>> - replace magic number in rtl8169_poll_msix_tx()
>>
>> Changes in v6:
>> - when irq_nvecs <= 1, use register IntrMask_8125, else using vec map
>> - fix irq sequence in rtl8169_interrupt_msix(), disable interrupts
>> before clean it
>> - remove dead code in rtl8169_poll_msix_tx()
>>
>> Changes in v7:
>> - remove recheck_desc_ownbit
>> - change return value of rtl_tx
>> - remove message_id which only used once
>>
>> Changes in v8:
>> - fix rtl8169_netpoll()
>> - remove tx_done
>>
>> Changes in v9:
>> - change the way of getting message_id of napi
>>
>> Changes in v10:
>> - no changes
>>
>> Changes in v11:
>> - add comment on rtl8169_poll_msix_tx, only use 1 tx
>> - remove napi for other. Separate napi only for datapath, control path
>> like linkchg is handled in interrupt function, which will not call
>> napi any more.
>> ---
>> drivers/net/ethernet/realtek/r8169_main.c | 213 +++++++++++++++++++---
>> 1 file changed, 187 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c
>> b/drivers/net/ethernet/realtek/r8169_main.c
>> index 9311a0cab4eb..b30f0a31d7c7 100644
>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>> @@ -84,6 +84,7 @@
>> #define R8169_RX_RING_BYTES ((NUM_RX_DESC + 1) * sizeof(struct
>RxDesc))
>> #define R8169_TX_STOP_THRS (MAX_SKB_FRAGS + 1)
>> #define R8169_TX_START_THRS (2 * R8169_TX_STOP_THRS)
>> +#define R8169_MAX_QUEUES 16
>> #define R8169_MAX_RX_QUEUES 8
>> #define R8169_DEFAULT_RX_QUEUES 1
>> #define R8169_MAX_TX_QUEUES 1
>> @@ -455,8 +456,12 @@ enum rtl8125_registers {
>> RSS_CTRL_8125 = 0x4500,
>> Q_NUM_CTRL_8125 = 0x4800,
>> EEE_TXIDLE_TIMER_8125 = 0x6048,
>> + IMR_CLEAR_VEC_MAP_REG = 0x0d00,
>> + ISR_VEC_MAP_REG = 0x0d04,
>> + IMR_SET_VEC_MAP_REG = 0x0d0c,
>> };
>>
>> +#define MSIX_ID_VEC_MAP_LINKCHG 29
>> #define LEDSEL_MASK_8125 0x23f
>>
>> #define RX_VLAN_INNER_8125 BIT(22)
>> @@ -587,6 +592,9 @@ enum rtl_register_content {
>>
>> /* magic enable v2 */
>> MagicPacket_v2 = (1 << 16), /* Wake up when receives a Magic Packet
>*/
>> +#define ISRIMR_LINKCHG BIT(29)
>> +#define ISRIMR_TOK_Q0 BIT(8)
>> +#define ISRIMR_ROK_Q0 BIT(0)
>> };
>>
>> enum rtl_desc_bit {
>> @@ -1663,26 +1671,38 @@ static u32 rtl_get_events(struct
>> rtl8169_private *tp)
>>
>> static void rtl_ack_events(struct rtl8169_private *tp, u32 bits)
>> {
>> - if (rtl_is_8125(tp))
>> - RTL_W32(tp, IntrStatus_8125, bits);
>> - else
>> + if (rtl_is_8125(tp)) {
>> + if (tp->irq_nvecs > 1)
>> + RTL_W32(tp, ISR_VEC_MAP_REG, bits);
>> + else
>> + RTL_W32(tp, IntrStatus_8125, bits);
>> + } else {
>> RTL_W16(tp, IntrStatus, bits);
>> + }
>> }
>>
>> static void rtl_irq_disable(struct rtl8169_private *tp)
>> {
>> - if (rtl_is_8125(tp))
>> - RTL_W32(tp, IntrMask_8125, 0);
>> - else
>> + if (rtl_is_8125(tp)) {
>> + if (tp->irq_nvecs > 1)
>> + RTL_W32(tp, IMR_CLEAR_VEC_MAP_REG, 0xffffffff);
>> + else
>> + RTL_W32(tp, IntrMask_8125, 0);
>> + } else {
>> RTL_W16(tp, IntrMask, 0);
>> + }
>> }
>>
>> static void rtl_irq_enable(struct rtl8169_private *tp)
>> {
>> - if (rtl_is_8125(tp))
>> - RTL_W32(tp, IntrMask_8125, tp->irq_mask);
>> - else
>> + if (rtl_is_8125(tp)) {
>> + if (tp->irq_nvecs > 1)
>> + RTL_W32(tp, IMR_SET_VEC_MAP_REG, tp->irq_mask);
>> + else
>> + RTL_W32(tp, IntrMask_8125, tp->irq_mask);
>> + } else {
>> RTL_W16(tp, IntrMask, tp->irq_mask);
>> + }
>> }
>>
>> static void rtl8169_irq_mask_and_ack(struct rtl8169_private *tp) @@
>> -4382,13 +4402,17 @@ static void rtl8169_tx_clear(struct
>> rtl8169_private *tp)
>>
>> static void rtl8169_napi_disable(struct rtl8169_private *tp)
>> {
>> - for (int i = 0; i < tp->irq_nvecs; i++)
>> + int napi_num = min(tp->irq_nvecs, R8169_MAX_QUEUES);
>> +
>> + for (int i = 0; i < napi_num; i++)
>> napi_disable(&tp->rtl8169_napi[i]);
>> }
>>
>> static void rtl8169_napi_enable(struct rtl8169_private *tp)
>> {
>> - for (int i = 0; i < tp->irq_nvecs; i++)
>> + int napi_num = min(tp->irq_nvecs, R8169_MAX_QUEUES);
>> +
>> + for (int i = 0; i < napi_num; i++)
>> napi_enable(&tp->rtl8169_napi[i]);
>> }
>>
>> @@ -5030,13 +5054,66 @@ static irqreturn_t rtl8169_interrupt(int irq, void
>*dev_instance)
>> return IRQ_HANDLED;
>> }
>>
>> +static void rtl8169_free_one_irq(struct rtl8169_private *tp, int i) {
>> + if (tp->irq_nvecs > 1) {
>> + if (i < R8169_MAX_QUEUES)
>> + pci_free_irq(tp->pci_dev, i, &tp->rtl8169_napi[i]);
>> + else if (i == MSIX_ID_VEC_MAP_LINKCHG)
>> + pci_free_irq(tp->pci_dev, i, tp);
>> + } else {
>> + pci_free_irq(tp->pci_dev, i, &tp->rtl8169_napi[i]);
>> + }
>> +}
>> +
>> static void rtl8169_free_irq(struct rtl8169_private *tp)
>> {
>> - for (int i = 0; i < tp->irq_nvecs; i++) {
>> - struct napi_struct *napi = &tp->rtl8169_napi[i];
>> + for (int i = 0; i < tp->irq_nvecs; i++)
>> + rtl8169_free_one_irq(tp, i); }
>>
>> - pci_free_irq(tp->pci_dev, i, napi);
>> - }
>> +static void rtl8169_disable_hw_interrupt_msix(struct rtl8169_private *tp,
>> + int message_id) {
>> + RTL_W32(tp, IMR_CLEAR_VEC_MAP_REG, BIT(message_id)); }
>> +
>> +static void rtl8169_clear_hw_isr(struct rtl8169_private *tp, int
>> +message_id) {
>> + RTL_W32(tp, ISR_VEC_MAP_REG, BIT(message_id)); }
>> +
>> +static void rtl8169_enable_hw_interrupt_msix(struct rtl8169_private *tp,
>> + int message_id) {
>> + RTL_W32(tp, IMR_SET_VEC_MAP_REG, BIT(message_id)); }
>> +
>> +static irqreturn_t rtl8169_interrupt_msix(int irq, void
>> +*dev_instance) {
>> + struct napi_struct *napi = dev_instance;
>> + struct net_device *dev = napi->dev;
>> + struct rtl8169_private *tp;
>> + int message_id;
>> +
>> + tp = netdev_priv(dev);
>> + message_id = napi - tp->rtl8169_napi;
>> +
>> + rtl8169_disable_hw_interrupt_msix(tp, message_id);
>> + rtl8169_clear_hw_isr(tp, message_id);
>> +
>> + napi_schedule(napi);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t rtl8169_interrupt_other(int irq, void
>> +*dev_instance) {
>> + struct rtl8169_private *tp = dev_instance;
>> +
>> + rtl8169_clear_hw_isr(tp, MSIX_ID_VEC_MAP_LINKCHG);
>> + phy_mac_interrupt(tp->phydev);
>> + return IRQ_HANDLED;
>> }
>>
>> static int rtl8169_request_irq(struct rtl8169_private *tp) @@
>> -5047,8 +5124,26 @@ static int rtl8169_request_irq(struct
>> rtl8169_private *tp)
>>
>> for (i = 0; i < tp->irq_nvecs; i++) {
>> napi = &tp->rtl8169_napi[i];
>> - rc = pci_request_irq(tp->pci_dev, i, rtl8169_interrupt,
>> - NULL, napi, "%s-%d", dev->name, i);
>> + if (tp->irq_nvecs > 1) {
>> + if (i < R8169_MAX_QUEUES)
>> + rc = pci_request_irq(tp->pci_dev, i,
>> + rtl8169_interrupt_msix,
>> + NULL, napi, "%s-%d",
>> + dev->name, i);
>> + else if (i == MSIX_ID_VEC_MAP_LINKCHG)
>> + rc = pci_request_irq(tp->pci_dev, i,
>> + rtl8169_interrupt_other,
>> + NULL, tp, "%s-%d",
>> + dev->name, i);
>> + else
>> + continue;
>> + } else {
>> + rc = pci_request_irq(tp->pci_dev, i,
>> + rtl8169_interrupt,
>> + NULL, napi, "%s-%d",
>> + dev->name, i);
>> + }
>> +
>> if (rc)
>> goto free_irq;
>> }
>> @@ -5056,7 +5151,7 @@ static int rtl8169_request_irq(struct
>> rtl8169_private *tp)
>>
>> free_irq:
>> while (--i >= 0)
>> - pci_free_irq(tp->pci_dev, i, &tp->rtl8169_napi[i]);
>> + rtl8169_free_one_irq(tp, i);
>> return rc;
>> }
>>
>> @@ -5255,8 +5350,12 @@ static void rtl8169_netpoll(struct net_device
>*dev)
>> struct rtl8169_private *tp = netdev_priv(dev);
>>
>> for (int i = 0; i < tp->irq_nvecs; i++) {
>
>Looking at r8169_init_napi(), later down the patch, it only calls
>netif_napi_add() for min(tp->irq_nvecs, R8169_MAX_QUEUES) vectors, but this
>loop iterates all tp->irq_nvecs. Can this be an issue? Looks like it will be
>because entries entries >= R8169_MAX_QUEUES are zeroed but
>rtl8169_interrupt_msix() would set dev to NULL.

Thanks for pointing out this. I have forgotten to modify this.

Thanks,
Javen