[Intel-wired-lan] [PATCH v3 04/11] igc: Add interrupt support

Neftin, Sasha sasha.neftin at intel.com
Tue Jul 3 08:25:41 UTC 2018


On 6/28/2018 02:42, Shannon Nelson wrote:
> On 6/24/2018 1:45 AM, Sasha Neftin wrote:
>> This patch set adds interrupt support for the igc interfaces.
>>
>> Sasha Neftin (v2):
>> fixed comments
>>
>> Sasha Neftin (v3):
>> minor changes
>>
>> Signed-off-by: Sasha Neftin <sasha.neftin at intel.com>
>> ---
>>   drivers/net/ethernet/intel/igc/e1000_defines.h |   35 +
>>   drivers/net/ethernet/intel/igc/e1000_hw.h      |   84 ++
>>   drivers/net/ethernet/intel/igc/e1000_regs.h    |    4 +-
>>   drivers/net/ethernet/intel/igc/igc.h           |  131 +++
>>   drivers/net/ethernet/intel/igc/igc_main.c      | 1068 
>> +++++++++++++++++++++++-
>>   5 files changed, 1305 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/igc/e1000_defines.h 
>> b/drivers/net/ethernet/intel/igc/e1000_defines.h
>> index 66b05898eb00..1f8bc16c7029 100644
>> --- a/drivers/net/ethernet/intel/igc/e1000_defines.h
>> +++ b/drivers/net/ethernet/intel/igc/e1000_defines.h
>> @@ -62,4 +62,39 @@
>>   #define E1000_STATUS_SPEED_100    0x00000040      /* Speed 100Mb/s */
>>   #define E1000_STATUS_SPEED_1000    0x00000080      /* Speed 1000Mb/s */
>> +/* Interrupt Cause Read */
>> +#define E1000_ICR_TXDW        0x00000001 /* Transmit desc written 
>> back */
>> +#define E1000_ICR_TXQE        0x00000002 /* Transmit Queue empty */
>> +#define E1000_ICR_LSC        0x00000004 /* Link Status Change */
>> +#define E1000_ICR_RXSEQ        0x00000008 /* Rx sequence error */
>> +#define E1000_ICR_RXDMT0    0x00000010 /* Rx desc min. threshold (0) */
>> +#define E1000_ICR_RXO        0x00000040 /* Rx overrun */
>> +#define E1000_ICR_RXT0        0x00000080 /* Rx timer intr (ring 0) */
>> +#define E1000_ICR_DRSTA        0x40000000 /* Device Reset Asserted */
>> +#define E1000_ICS_RXT0        E1000_ICR_RXT0      /* Rx timer intr */
> 
> An argument might be made that all these bit definitions should be in 
> the form of BIT(x), especially when you're using BIT(x) in other 
> definitions such as IGC_FLAG_HAS_MSI.
> 
>> +
>> +#define IMS_ENABLE_MASK ( \
> 
> Should have the driver name prefix
> 
>> +    E1000_IMS_RXT0   |    \
>> +    E1000_IMS_TXDW   |    \
>> +    E1000_IMS_RXDMT0 |    \
>> +    E1000_IMS_RXSEQ  |    \
>> +    E1000_IMS_LSC)
>> +
>> +/* Interrupt Mask Set */
>> +#define E1000_IMS_TXDW        E1000_ICR_TXDW    /* Tx desc written 
>> back */
>> +#define E1000_IMS_RXSEQ        E1000_ICR_RXSEQ   /* Rx sequence error */
>> +#define E1000_IMS_LSC        E1000_ICR_LSC    /* Link Status Change */
>> +#define E1000_IMS_DOUTSYNC    E1000_ICR_DOUTSYNC /* NIC DMA out of 
>> sync */
>> +#define E1000_IMS_DRSTA        E1000_ICR_DRSTA   /* Device Reset 
>> Asserted */
>> +#define E1000_IMS_RXT0        E1000_ICR_RXT0    /* Rx timer intr */
>> +#define E1000_IMS_RXDMT0    E1000_ICR_RXDMT0  /* Rx desc min. 
>> threshold */
>> +
>> +#define E1000_ICR_DOUTSYNC    0x10000000 /* NIC DMA out of sync */
>> +#define E1000_EITR_CNT_IGNR    0x80000000 /* Don't reset counters on 
>> write */
>> +#define E1000_IVAR_VALID    0x80
>> +#define E1000_GPIE_NSICR    0x00000001
>> +#define E1000_GPIE_MSIX_MODE    0x00000010
>> +#define E1000_GPIE_EIAME    0x40000000
>> +#define E1000_GPIE_PBA        0x80000000
>> +
>>   #endif /* _E1000_DEFINES_H_ */
>> diff --git a/drivers/net/ethernet/intel/igc/e1000_hw.h 
>> b/drivers/net/ethernet/intel/igc/e1000_hw.h
>> index 6abe722f0bc4..650c4ac981d9 100644
>> --- a/drivers/net/ethernet/intel/igc/e1000_hw.h
>> +++ b/drivers/net/ethernet/intel/igc/e1000_hw.h
>> @@ -118,6 +118,90 @@ struct e1000_hw {
>>       u8  revision_id;
>>   };
>> +/* Statistics counters collected by the MAC */
>> +struct e1000_hw_stats {
>> +    u64 crcerrs;
>> +    u64 algnerrc;
>> +    u64 symerrs;
>> +    u64 rxerrc;
>> +    u64 mpc;
>> +    u64 scc;
>> +    u64 ecol;
>> +    u64 mcc;
>> +    u64 latecol;
>> +    u64 colc;
>> +    u64 dc;
>> +    u64 tncrs;
>> +    u64 sec;
>> +    u64 cexterr;
>> +    u64 rlec;
>> +    u64 xonrxc;
>> +    u64 xontxc;
>> +    u64 xoffrxc;
>> +    u64 xofftxc;
>> +    u64 fcruc;
>> +    u64 prc64;
>> +    u64 prc127;
>> +    u64 prc255;
>> +    u64 prc511;
>> +    u64 prc1023;
>> +    u64 prc1522;
>> +    u64 gprc;
>> +    u64 bprc;
>> +    u64 mprc;
>> +    u64 gptc;
>> +    u64 gorc;
>> +    u64 gotc;
>> +    u64 rnbc;
>> +    u64 ruc;
>> +    u64 rfc;
>> +    u64 roc;
>> +    u64 rjc;
>> +    u64 mgprc;
>> +    u64 mgpdc;
>> +    u64 mgptc;
>> +    u64 tor;
>> +    u64 tot;
>> +    u64 tpr;
>> +    u64 tpt;
>> +    u64 ptc64;
>> +    u64 ptc127;
>> +    u64 ptc255;
>> +    u64 ptc511;
>> +    u64 ptc1023;
>> +    u64 ptc1522;
>> +    u64 mptc;
>> +    u64 bptc;
>> +    u64 tsctc;
>> +    u64 tsctfc;
>> +    u64 iac;
>> +    u64 icrxptc;
>> +    u64 icrxatc;
>> +    u64 ictxptc;
>> +    u64 ictxatc;
>> +    u64 ictxqec;
>> +    u64 ictxqmtc;
>> +    u64 icrxdmtc;
>> +    u64 icrxoc;
>> +    u64 cbtmpc;
>> +    u64 htdpmc;
>> +    u64 cbrdpc;
>> +    u64 cbrmpc;
>> +    u64 rpthc;
>> +    u64 hgptc;
>> +    u64 htcbdpc;
>> +    u64 hgorc;
>> +    u64 hgotc;
>> +    u64 lenerrs;
>> +    u64 scvpc;
>> +    u64 hrmpc;
>> +    u64 doosync;
>> +    u64 o2bgptc;
>> +    u64 o2bspc;
>> +    u64 b2ospc;
>> +    u64 b2ogprc;
>> +};
>> +
>>   /* These functions must be implemented by drivers */
>>   s32  igc_read_pcie_cap_reg(struct e1000_hw *hw, u32 reg, u16 *value);
>>   s32  igc_write_pcie_cap_reg(struct e1000_hw *hw, u32 reg, u16 *value);
>> diff --git a/drivers/net/ethernet/intel/igc/e1000_regs.h 
>> b/drivers/net/ethernet/intel/igc/e1000_regs.h
>> index 4a1da691f42c..5634a01afff3 100644
>> --- a/drivers/net/ethernet/intel/igc/e1000_regs.h
>> +++ b/drivers/net/ethernet/intel/igc/e1000_regs.h
>> @@ -70,8 +70,8 @@
>>   #define E1000_IAM        0x01510  /* Intr Ack Auto Mask- RW */
>>   /* Intr Throttle - RW */
>>   #define E1000_EITR(_n)        (0x01680 + (0x4 * (_n)))
>> -/* Interrupt Vector Allocation (array) - RW */
>> -#define E1000_IVAR(_n)        (0x01700 + (0x4 * (_n)))
>> +/* Interrupt Vector Allocation - RW */
>> +#define E1000_IVAR0        0x01700
>>   #define E1000_IVAR_MISC        0x01740   /* IVAR for "other" causes 
>> - RW */
>>   #define E1000_GPIE        0x01514  /* General Purpose Intr Enable - 
>> RW */
>> diff --git a/drivers/net/ethernet/intel/igc/igc.h 
>> b/drivers/net/ethernet/intel/igc/igc.h
>> index 29df87285b9b..7cab3e9c8e91 100644
>> --- a/drivers/net/ethernet/intel/igc/igc.h
>> +++ b/drivers/net/ethernet/intel/igc/igc.h
>> @@ -28,6 +28,17 @@
>>   extern char igc_driver_name[];
>>   extern char igc_driver_version[];
>> +/* Interrupt defines */
>> +#define IGC_START_ITR            648 /* ~6000 ints/sec */
>> +#define IGC_FLAG_HAS_MSI        BIT(0)
>> +#define IGC_FLAG_QUEUE_PAIRS        BIT(4)
>> +#define IGC_FLAG_HAS_MSIX        BIT(13)
>> +
>> +#define IGC_START_ITR            648 /* ~6000 ints/sec */
>> +#define IGC_4K_ITR            980
>> +#define IGC_20K_ITR            196
>> +#define IGC_70K_ITR            56
>> +
>>   /* Transmit and receive queues */
>>   #define IGC_MAX_RX_QUEUES                 4
>>   #define IGC_MAX_TX_QUEUES                 4
>> @@ -42,10 +53,100 @@ enum e1000_state_t {
>>        __IGC_PTP_TX_IN_PROGRESS,
>>   };
>> +struct igc_tx_queue_stats {
>> +    u64 packets;
>> +    u64 bytes;
>> +    u64 restart_queue;
>> +};
>> +
>> +struct igc_rx_queue_stats {
>> +    u64 packets;
>> +    u64 bytes;
>> +    u64 drops;
>> +    u64 csum_err;
>> +    u64 alloc_failed;
>> +};
>> +
>> +struct igc_rx_packet_stats {
>> +    u64 ipv4_packets;      /* IPv4 headers processed */
>> +    u64 ipv4e_packets;     /* IPv4E headers with extensions processed */
>> +    u64 ipv6_packets;      /* IPv6 headers processed */
>> +    u64 ipv6e_packets;     /* IPv6E headers with extensions processed */
>> +    u64 tcp_packets;       /* TCP headers processed */
>> +    u64 udp_packets;       /* UDP headers processed */
>> +    u64 sctp_packets;      /* SCTP headers processed */
>> +    u64 nfs_packets;       /* NFS headers processe */
>> +    u64 other_packets;
>> +};
>> +
>> +struct igc_ring_container {
>> +    struct igc_ring *ring;          /* pointer to linked list of 
>> rings */
>> +    unsigned int total_bytes;       /* total bytes processed this int */
>> +    unsigned int total_packets;     /* total packets processed this 
>> int */
>> +    u16 work_limit;                 /* total work allowed per 
>> interrupt */
>> +    u8 count;                       /* total number of rings in 
>> vector */
>> +    u8 itr;                         /* current ITR setting for ring */
>> +};
>> +
>> +struct igc_ring {
>> +    struct igc_q_vector *q_vector;  /* backlink to q_vector */
>> +    struct net_device *netdev;      /* back pointer to net_device */
>> +    struct device *dev;             /* device for dma mapping */
>> +    union {                         /* array of buffer info structs */
>> +        struct igc_tx_buffer *tx_buffer_info;
>> +        struct igc_rx_buffer *rx_buffer_info;
>> +    };
>> +    void *desc;                     /* descriptor ring memory */
>> +    unsigned long flags;            /* ring specific flags */
>> +    void __iomem *tail;             /* pointer to ring tail register */
>> +    dma_addr_t dma;                 /* phys address of the ring */
>> +    unsigned int size;              /* length of desc. ring in bytes */
> 
> I'm amused and curious about your mix of long/int and u8/u16/u32.  I'd 
> prefer to see a little more consistency in a new driver.  Is there a 
> reason for unsigned int here rather than u32?  Or for the long flags 
> rather than u64 flags?
> 
>> +
>> +    u16 count;                      /* number of desc. in the ring */
>> +    u8 queue_index;                 /* logical index of the ring*/
>> +    u8 reg_idx;                     /* physical index of the ring */
>> +
>> +    /* everything past this point are written often */
>> +    u16 next_to_clean;
>> +    u16 next_to_use;
>> +    u16 next_to_alloc;
>> +
>> +    union {
>> +        /* TX */
>> +        struct {
>> +            struct igc_tx_queue_stats tx_stats;
>> +        };
>> +        /* RX */
>> +        struct {
>> +            struct igc_rx_queue_stats rx_stats;
>> +            struct igc_rx_packet_stats pkt_stats;
>> +#ifdef CONFIG_IGC_DISABLE_PACKET_SPLIT
>> +            u16 rx_buffer_len;
>> +#else
>> +            struct sk_buff *skb;
>> +#endif
>> +        };
>> +    };
>> +} ____cacheline_internodealigned_in_smp;
>> +
>>   struct igc_q_vector {
>>       struct igc_adapter *adapter;    /* backlink */
>> +    void __iomem *itr_register;
>> +    u32 eims_value;                 /* EIMS mask value */
>> +
>> +    u16 itr_val;
>> +    u8 set_itr;
>> +
>> +    struct igc_ring_container rx, tx;
>>       struct napi_struct napi;
>> +
>> +    struct rcu_head rcu;    /* to avoid race with update stats on 
>> free */
>> +    char name[IFNAMSIZ + 9];
>> +    struct net_device poll_dev;
>> +
>> +    /* for dynamic allocation of rings associated with this q_vector */
>> +    struct igc_ring ring[0] ____cacheline_internodealigned_in_smp;
>>   };
>>   struct igc_mac_addr {
>> @@ -65,13 +166,35 @@ struct igc_adapter {
>>       unsigned long state;
>>       unsigned int flags;
>>       unsigned int num_q_vectors;
>> +
>> +    struct msix_entry *msix_entries;
>> +
>> +    /* TX */
>> +    u16 tx_work_limit;
>> +    int num_tx_queues;
>> +    struct igc_ring *tx_ring[IGC_MAX_TX_QUEUES];
>> +
>> +    /* RX */
>> +    int num_rx_queues;
>> +    struct igc_ring *rx_ring[IGC_MAX_RX_QUEUES];
>> +
>> +    struct timer_list watchdog_timer;
>> +    struct timer_list dma_err_timer;
>> +    struct timer_list phy_info_timer;
>> +
>>       u16 link_speed;
>>       u16 link_duplex;
>>       u8 port_num;
>>       u8 __iomem *io_addr;
>> +    /* Interrupt Throttle Rate */
>> +    u32 rx_itr_setting;
>> +    u32 tx_itr_setting;
>> +
>> +    struct work_struct reset_task;
>>       struct work_struct watchdog_task;
>> +    struct work_struct dma_err_task;
>>       int msg_enable;
>>       u32 max_frame_size;
>> @@ -81,8 +204,16 @@ struct igc_adapter {
>>       /* structs defined in e1000_hw.h */
>>       struct e1000_hw hw;
>> +    struct e1000_hw_stats stats;
>>       struct igc_q_vector *q_vector[MAX_Q_VECTORS];
>> +    u32 eims_enable_mask;
>> +    u32 eims_other;
>> +
>> +    u16 tx_ring_count;
>> +    u16 rx_ring_count;
>> +
>> +    u32 rss_queues;
>>       struct igc_mac_addr *mac_table;
>>   };
>> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c 
>> b/drivers/net/ethernet/intel/igc/igc_main.c
>> index 520f49be8e19..30b778c9b94b 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_main.c
>> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
>> @@ -33,6 +33,36 @@ static int igc_sw_init(struct igc_adapter *);
>>   static void igc_configure(struct igc_adapter *adapter);
>>   static void igc_power_down_link(struct igc_adapter *adapter);
>>   static void igc_set_default_mac_filter(struct igc_adapter *adapter);
>> +static irqreturn_t igc_msix_ring(int irq, void *data);
>> +static void igc_write_itr(struct igc_q_vector *q_vector);
>> +static int igc_request_msix(struct igc_adapter *adapter);
>> +static void igc_assign_vector(struct igc_q_vector *q_vector, int 
>> msix_vector);
>> +static void igc_free_q_vector(struct igc_adapter *adapter, int v_idx);
>> +static int igc_init_interrupt_scheme(struct igc_adapter *adapter, 
>> bool msix);
>> +static int igc_alloc_q_vectors(struct igc_adapter *adapter);
>> +static int igc_poll(struct napi_struct *napi, int budget);
>> +static void igc_set_interrupt_capability(struct igc_adapter *adapter,
>> +                     bool msix);
>> +static void igc_reset_interrupt_capability(struct igc_adapter *adapter);
>> +static void igc_reset_q_vector(struct igc_adapter *adapter, int v_idx);
>> +static void igc_clear_interrupt_scheme(struct igc_adapter *adapter);
>> +static void igc_free_q_vectors(struct igc_adapter *adapter);
>> +static void igc_irq_disable(struct igc_adapter *adapter);
>> +static void igc_irq_enable(struct igc_adapter *adapter);
>> +static void igc_configure_msix(struct igc_adapter *adapter);
>> +static void igc_free_irq(struct igc_adapter *adapter);
>> +static void igc_ring_irq_enable(struct igc_q_vector *q_vector);
>> +static void igc_set_itr(struct igc_q_vector *q_vector);
>> +static void igc_update_ring_itr(struct igc_q_vector *q_vector);
>> +static void igc_update_itr(struct igc_q_vector *q_vector,
>> +               struct igc_ring_container *ring_container);
>> +
>> +enum latency_range {
>> +    lowest_latency = 0,
>> +    low_latency = 1,
>> +    bulk_latency = 2,
>> +    latency_invalid = 255
>> +};
>>   void igc_reset(struct igc_adapter *adapter)
>>   {
>> @@ -146,6 +176,7 @@ static int igc_ioctl(struct net_device *netdev, 
>> struct ifreq *ifr, int cmd)
>>    **/
>>   int igc_up(struct igc_adapter *adapter)
>>   {
>> +    struct e1000_hw *hw = &adapter->hw;
>>       int i = 0;
>>       /* hardware has been reset, we need to reload some things */
>> @@ -156,6 +187,15 @@ int igc_up(struct igc_adapter *adapter)
>>       for (i = 0; i < adapter->num_q_vectors; i++)
>>           napi_enable(&adapter->q_vector[i]->napi);
>> +    if (adapter->msix_entries)
>> +        igc_configure_msix(adapter);
>> +    else
>> +        igc_assign_vector(adapter->q_vector[0], 0);
>> +
>> +    /* Clear any pending interrupts. */
>> +    rd32(E1000_ICR);
>> +    igc_irq_enable(adapter);
>> +
>>       return 0;
>>   }
>> @@ -303,23 +343,985 @@ static void igc_set_default_mac_filter(struct 
>> igc_adapter *adapter)
>>       igc_rar_set_index(adapter, 0);
>>   }
>> +static irqreturn_t igc_msix_other(int irq, void *data)
> 
> Are you going to put header comments on these functions later, or leave 
> it with some lacking headers?
> 
good. Add header. fix will be applied in v4.
>> +{
>> +    struct igc_adapter *adapter = data;
>> +    struct e1000_hw *hw = &adapter->hw;
>> +    u32 icr = rd32(E1000_ICR);
>> +    /* reading ICR causes bit 31 of EICR to be cleared */
>> +
>> +    if (icr & E1000_ICR_DRSTA)
>> +        schedule_work(&adapter->reset_task);
>> +
>> +    if (icr & E1000_ICR_DOUTSYNC) {
>> +        /* HW is reporting DMA is out of sync */
>> +        adapter->stats.doosync++;
>> +    }
>> +
>> +    if (icr & E1000_ICR_LSC) {
>> +        hw->mac.get_link_status = 1;
>> +        /* guard against interrupt when we're going down */
>> +        if (!test_bit(__IGC_DOWN, &adapter->state))
>> +            mod_timer(&adapter->watchdog_timer, jiffies + 1);
>> +    }
>> +
>> +    wr32(E1000_EIMS, adapter->eims_other);
>> +
>> +    return IRQ_HANDLED;
>> +}
>> +
>> +/**
>> + *  igc_write_ivar - configure ivar for given MSI-X vector
>> + *  @hw: pointer to the HW structure
>> + *  @msix_vector: vector number we are allocating to a given ring
>> + *  @index: row index of IVAR register to write within IVAR table
>> + *  @offset: column offset of in IVAR, should be multiple of 8
>> + *
>> + *  This function is intended to handle the writing of the IVAR register
>> + *  for adapters 82576 and newer.  The IVAR table consists of 2 columns,
> 
> I suspect this driver won't be handling 82576.
> 
right. fix will be applied in v4.
>> + *  each containing an cause allocation for an Rx and Tx ring, and a
>> + *  variable number of rows depending on the number of queues supported.
>> + **/
>> +static void igc_write_ivar(struct e1000_hw *hw, int msix_vector,
>> +               int index, int offset)
>> +{
>> +    u32 ivar = array_rd32(E1000_IVAR0, index);
>> +
>> +    /* clear any bits that are currently set */
>> +    ivar &= ~((u32)0xFF << offset);
>> +
>> +    /* write vector and valid bit */
>> +    ivar |= (msix_vector | E1000_IVAR_VALID) << offset;
>> +
>> +    array_wr32(E1000_IVAR0, index, ivar);
>> +}
>> +
>> +#define IGC_N0_QUEUE -1
> 
> Put this in a .h file
> 
Good point. Move to .h fix will be applied in v4.
>> +static void igc_assign_vector(struct igc_q_vector *q_vector, int 
>> msix_vector)
>> +{
>> +    struct igc_adapter *adapter = q_vector->adapter;
>> +    struct e1000_hw *hw = &adapter->hw;
>> +    int rx_queue = IGC_N0_QUEUE;
>> +    int tx_queue = IGC_N0_QUEUE;
>> +
>> +    if (q_vector->rx.ring)
>> +        rx_queue = q_vector->rx.ring->reg_idx;
>> +    if (q_vector->tx.ring)
>> +        tx_queue = q_vector->tx.ring->reg_idx;
>> +
>> +    switch (hw->mac.type) {
>> +    case e1000_i225:
>> +        if (rx_queue > IGC_N0_QUEUE)
>> +            igc_write_ivar(hw, msix_vector,
>> +                       rx_queue >> 1,
>> +                       (rx_queue & 0x1) << 4);
>> +        if (tx_queue > IGC_N0_QUEUE)
>> +            igc_write_ivar(hw, msix_vector,
>> +                       tx_queue >> 1,
>> +                       ((tx_queue & 0x1) << 4) + 8);
>> +        q_vector->eims_value = BIT(msix_vector);
>> +        break;
>> +    default:
>> +        WARN_ON(hw->mac.type != e1000_i225);
> 
> You might want to make this a WARN_ONCE
> 
>> +        break;
>> +    }
>> +
>> +    /* add q_vector eims value to global eims_enable_mask */
>> +    adapter->eims_enable_mask |= q_vector->eims_value;
>> +
>> +    /* configure q_vector to set itr on first interrupt */
>> +    q_vector->set_itr = 1;
>> +}
>> +
>> +/**
>> + *  igc_configure_msix - Configure MSI-X hardware
>> + *  @adapter: Pointer to adapter structure
>> + *
>> + *  igc_configure_msix sets up the hardware to properly
>> + *  generate MSI-X interrupts.
>> + **/
>> +static void igc_configure_msix(struct igc_adapter *adapter)
>> +{
>> +    u32 tmp;
>> +    int i, vector = 0;
>> +    struct e1000_hw *hw = &adapter->hw;
> 
> reverse xmas tree layout
> 
good. fix will be apples in v4.
>> +
>> +    adapter->eims_enable_mask = 0;
>> +
>> +    /* set vector for other causes, i.e. link changes */
>> +    switch (hw->mac.type) {
>> +    case e1000_i225:
>> +        /* Turn on MSI-X capability first, or our settings
>> +         * won't stick.  And it will take days to debug.
>> +         */
>> +        wr32(E1000_GPIE, E1000_GPIE_MSIX_MODE |
>> +             E1000_GPIE_PBA | E1000_GPIE_EIAME |
>> +             E1000_GPIE_NSICR);
>> +
>> +        /* enable msix_other interrupt */
>> +        adapter->eims_other = BIT(vector);
>> +        tmp = (vector++ | E1000_IVAR_VALID) << 8;
>> +
>> +        wr32(E1000_IVAR_MISC, tmp);
>> +        break;
>> +    default:
>> +        /* do nothing, since nothing else supports MSI-X */
> 
> Will there be hardware used by this driver that *doesn't* support MSIx? 
> If not then this is a misleading comment.  This case is more likely a 
> good place for an error message for unexpected HW.
> 
>> +        break;
>> +    } /* switch (hw->mac.type) */
>> +
>> +    adapter->eims_enable_mask |= adapter->eims_other;
>> +
>> +    for (i = 0; i < adapter->num_q_vectors; i++)
>> +        igc_assign_vector(adapter->q_vector[i], vector++);
>> +
>> +    wrfl();
>> +}
>> +
>> +/**
>> + *  igc_request_msix - Initialize MSI-X interrupts
>> + *  @adapter: Pointer to adapter structure
>> + *
>> + *  igc_request_msix allocates MSI-X vectors and requests interrupts 
>> from the
>> + *  kernel.
>> + **/
>> +static int igc_request_msix(struct igc_adapter *adapter)
>> +{
>> +    struct net_device *netdev = adapter->netdev;
>> +    int i = 0, err = 0, vector = 0, free_vector = 0;
> 
> reverse xmas tree
> 
good. fix will be applied in v4.
>> +
>> +    err = request_irq(adapter->msix_entries[vector].vector,
>> +              &igc_msix_other, 0, netdev->name, adapter);
>> +    if (err)
>> +        goto err_out;
>> +
>> +    for (i = 0; i < adapter->num_q_vectors; i++) {
>> +        struct igc_q_vector *q_vector = adapter->q_vector[i];
>> +
>> +        vector++;
>> +
>> +        q_vector->itr_register = adapter->io_addr + E1000_EITR(vector);
>> +
>> +        if (q_vector->rx.ring && q_vector->tx.ring)
>> +            sprintf(q_vector->name, "%s-TxRx-%u", netdev->name,
>> +                q_vector->rx.ring->queue_index);
>> +        else if (q_vector->tx.ring)
>> +            sprintf(q_vector->name, "%s-tx-%u", netdev->name,
>> +                q_vector->tx.ring->queue_index);
>> +        else if (q_vector->rx.ring)
>> +            sprintf(q_vector->name, "%s-rx-%u", netdev->name,
>> +                q_vector->rx.ring->queue_index);
> 
> Is there any reason to support the tx and rx queues split on different 
> interrupts?
> 
>> +        else
>> +            sprintf(q_vector->name, "%s-unused", netdev->name);
>> +
>> +        err = request_irq(adapter->msix_entries[vector].vector,
>> +                  igc_msix_ring, 0, q_vector->name,
>> +                  q_vector);
>> +        if (err)
>> +            goto err_free;
>> +    }
>> +
>> +    igc_configure_msix(adapter);
>> +    return 0;
>> +
>> +err_free:
>> +    /* free already assigned IRQs */
>> +    free_irq(adapter->msix_entries[free_vector++].vector, adapter);
>> +
>> +    vector--;
>> +    for (i = 0; i < vector; i++) {
>> +        free_irq(adapter->msix_entries[free_vector++].vector,
>> +             adapter->q_vector[i]);
>> +    }
>> +err_out:
>> +    return err;
>> +}
>> +
>> +/**
>> + *  igc_reset_q_vector - Reset config for interrupt vector
>> + *  @adapter: board private structure to initialize
>> + *  @v_idx: Index of vector to be reset
>> + *
>> + *  If NAPI is enabled it will delete any references to the
>> + *  NAPI struct. This is preparation for igc_free_q_vector.
>> + **/
>> +static void igc_reset_q_vector(struct igc_adapter *adapter, int v_idx)
>> +{
>> +    struct igc_q_vector *q_vector = adapter->q_vector[v_idx];
>> +
>> +    /* if we're coming from igc_set_interrupt_capability, the vectors 
>> are
>> +     * not yet allocated
>> +     */
>> +    if (!q_vector)
>> +        return;
>> +
>> +    if (q_vector->tx.ring)
>> +        adapter->tx_ring[q_vector->tx.ring->queue_index] = NULL;
>> +
>> +    if (q_vector->rx.ring)
>> +        adapter->rx_ring[q_vector->rx.ring->queue_index] = NULL;
>> +
>> +    netif_napi_del(&q_vector->napi);
>> +}
>> +
>> +static void igc_reset_interrupt_capability(struct igc_adapter *adapter)
>> +{
>> +    int v_idx = adapter->num_q_vectors;
>> +
>> +    if (adapter->msix_entries) {
>> +        pci_disable_msix(adapter->pdev);
>> +        kfree(adapter->msix_entries);
>> +        adapter->msix_entries = NULL;
>> +    } else if (adapter->flags & IGC_FLAG_HAS_MSI) {
>> +        pci_disable_msi(adapter->pdev);
>> +    }
>> +
>> +    while (v_idx--)
>> +        igc_reset_q_vector(adapter, v_idx);
>> +}
>> +
>>   /**
>> - * igc_open - Called when a network interface is made active
>> - * @netdev: network interface device structure
>> + *  igc_clear_interrupt_scheme - reset the device to a state of no 
>> interrupts
>> + *  @adapter: Pointer to adapter structure
>> + *
>> + *  This function resets the device so that it has 0 rx queues, tx 
>> queues, and
>> + *  MSI-X interrupts allocated.
>> + */
>> +static void igc_clear_interrupt_scheme(struct igc_adapter *adapter)
>> +{
>> +    igc_free_q_vectors(adapter);
>> +    igc_reset_interrupt_capability(adapter);
>> +}
>> +
>> +/**
>> + *  igc_free_q_vectors - Free memory allocated for interrupt vectors
>> + *  @adapter: board private structure to initialize
>> + *
>> + *  This function frees the memory allocated to the q_vectors.  In 
>> addition if
>> + *  NAPI is enabled it will delete any references to the NAPI struct 
>> prior
>> + *  to freeing the q_vector.
>> + **/
>> +static void igc_free_q_vectors(struct igc_adapter *adapter)
>> +{
>> +    int v_idx = adapter->num_q_vectors;
>> +
>> +    adapter->num_tx_queues = 0;
>> +    adapter->num_rx_queues = 0;
>> +    adapter->num_q_vectors = 0;
>> +
>> +    while (v_idx--) {
>> +        igc_reset_q_vector(adapter, v_idx);
>> +        igc_free_q_vector(adapter, v_idx);
>> +    }
>> +}
>> +
>> +/**
>> + *  igc_free_q_vector - Free memory allocated for specific interrupt 
>> vector
>> + *  @adapter: board private structure to initialize
>> + *  @v_idx: Index of vector to be freed
>>    *
>> - * Returns 0 on success, negative value on failure
>> + *  This function frees the memory allocated to the q_vector.
>> + **/
>> +static void igc_free_q_vector(struct igc_adapter *adapter, int v_idx)
>> +{
>> +    struct igc_q_vector *q_vector = adapter->q_vector[v_idx];
>> +
>> +    adapter->q_vector[v_idx] = NULL;
>> +
>> +    /* igc_get_stats64() might access the rings on this vector,
>> +     * we must wait a grace period before freeing it.
>> +     */
>> +    if (q_vector)
>> +        kfree_rcu(q_vector, rcu);
>> +}
>> +
>> +/**
>> + *  igc_update_ring_itr - update the dynamic ITR value based on 
>> packet size
>> + *  @q_vector: pointer to q_vector
>> + *
>> + *  Stores a new ITR value based on strictly on packet size.  This
>> + *  algorithm is less sophisticated than that used in igc_update_itr,
>> + *  due to the difficulty of synchronizing statistics across multiple
>> + *  receive rings.  The divisors and thresholds used by this function
>> + *  were determined based on theoretical maximum wire speed and testing
>> + *  data, in order to minimize response time while increasing bulk
>> + *  throughput.
> 
> Was this actually tested with the new HW?  This looks like more simple 
> cut-n-paste from igb.  I would assume that the new HW has slightly 
> different characteristics.
> 
>> + *  This functionality is controlled by the InterruptThrottleRate module
>> + *  parameter (see igc_param.c)
> 
> Since this is the in-kernel driver, I suspect there won't be an 
> InterruptThrottleRate module parameter or a igc_param.c file.
> 
>> + *  NOTE: This function is called only when operating in a multiqueue
>> + *  receive environment.
>> + **/
>> +static void igc_update_ring_itr(struct igc_q_vector *q_vector)
>> +{
>> +    int new_val = q_vector->itr_val;
>> +    int avg_wire_size = 0;
>> +    struct igc_adapter *adapter = q_vector->adapter;
>> +    unsigned int packets;
>> +
>> +    /* For non-gigabit speeds, just fix the interrupt rate at 4000
>> +     * ints/sec - ITR timer value of 120 ticks.
>> +     */
>> +    switch (adapter->link_speed) {
>> +    case SPEED_10:
>> +    case SPEED_100:
>> +        new_val = IGC_4K_ITR;
>> +        goto set_itr_val;
>> +    default:
>> +        break;
>> +    }
>> +
>> +    packets = q_vector->rx.total_packets;
>> +    if (packets)
>> +        avg_wire_size = q_vector->rx.total_bytes / packets;
>> +
>> +    packets = q_vector->tx.total_packets;
>> +    if (packets)
>> +        avg_wire_size = max_t(u32, avg_wire_size,
>> +                      q_vector->tx.total_bytes / packets);
>> +
>> +    /* if avg_wire_size isn't set no work was done */
>> +    if (!avg_wire_size)
>> +        goto clear_counts;
>> +
>> +    /* Add 24 bytes to size to account for CRC, preamble, and gap */
>> +    avg_wire_size += 24;
>> +
>> +    /* Don't starve jumbo frames */
>> +    avg_wire_size = min(avg_wire_size, 3000);
>> +
>> +    /* Give a little boost to mid-size frames */
>> +    if (avg_wire_size > 300 && avg_wire_size < 1200)
>> +        new_val = avg_wire_size / 3;
>> +    else
>> +        new_val = avg_wire_size / 2;
>> +
>> +    /* conservative mode (itr 3) eliminates the lowest_latency 
>> setting */
>> +    if (new_val < IGC_20K_ITR &&
>> +        ((q_vector->rx.ring && adapter->rx_itr_setting == 3) ||
>> +        (!q_vector->rx.ring && adapter->tx_itr_setting == 3)))
>> +        new_val = IGC_20K_ITR;
>> +
>> +set_itr_val:
>> +    if (new_val != q_vector->itr_val) {
>> +        q_vector->itr_val = new_val;
>> +        q_vector->set_itr = 1;
>> +    }
>> +clear_counts:
>> +    q_vector->rx.total_bytes = 0;
>> +    q_vector->rx.total_packets = 0;
>> +    q_vector->tx.total_bytes = 0;
>> +    q_vector->tx.total_packets = 0;
>> +}
>> +
>> +/**
>> + *  igc_update_itr - update the dynamic ITR value based on statistics
>> + *  @q_vector: pointer to q_vector
>> + *  @ring_container: ring info to update the itr for
>>    *
>> - * The open entry point is called when a network interface is made
>> - * active by the system (IFF_UP).  At this point all resources needed
>> - * for transmit and receive operations are allocated, the interrupt
>> - * handler is registered with the OS, the watchdog timer is started,
>> - * and the stack is notified that the interface is ready.
>> + *  Stores a new ITR value based on packets and byte
>> + *  counts during the last interrupt.  The advantage of per interrupt
>> + *  computation is faster updates and more accurate ITR for the current
>> + *  traffic pattern.  Constants in this function were computed
>> + *  based on theoretical maximum wire speed and thresholds were set 
>> based
>> + *  on testing data as well as attempting to minimize response time
> 
> Again - actual testing data on the new hardware?
> 
>> + *  while increasing bulk throughput.
>> + *  this functionality is controlled by the InterruptThrottleRate module
>> + *  parameter (see igc_param.c)
> 
> No module parameter or file in this driver?
> 
>> + *  NOTE: These calculations are only valid when operating in a single-
>> + *  queue environment.
>> + **/
>> +static void igc_update_itr(struct igc_q_vector *q_vector,
>> +               struct igc_ring_container *ring_container)
>> +{
>> +    unsigned int packets = ring_container->total_packets;
>> +    unsigned int bytes = ring_container->total_bytes;
>> +    u8 itrval = ring_container->itr;
>> +
>> +    /* no packets, exit with status unchanged */
>> +    if (packets == 0)
>> +        return;
>> +
>> +    switch (itrval) {
>> +    case lowest_latency:
>> +        /* handle TSO and jumbo frames */
>> +        if (bytes / packets > 8000)
>> +            itrval = bulk_latency;
>> +        else if ((packets < 5) && (bytes > 512))
>> +            itrval = low_latency;
>> +        break;
>> +    case low_latency:  /* 50 usec aka 20000 ints/s */
>> +        if (bytes > 10000) {
>> +            /* this if handles the TSO accounting */
>> +            if (bytes / packets > 8000)
>> +                itrval = bulk_latency;
>> +            else if ((packets < 10) || ((bytes / packets) > 1200))
>> +                itrval = bulk_latency;
>> +            else if ((packets > 35))
>> +                itrval = lowest_latency;
>> +        } else if (bytes / packets > 2000) {
>> +            itrval = bulk_latency;
>> +        } else if (packets <= 2 && bytes < 512) {
>> +            itrval = lowest_latency;
>> +        }
>> +        break;
>> +    case bulk_latency: /* 250 usec aka 4000 ints/s */
>> +        if (bytes > 25000) {
>> +            if (packets > 35)
>> +                itrval = low_latency;
>> +        } else if (bytes < 1500) {
>> +            itrval = low_latency;
>> +        }
>> +        break;
>> +    }
>> +
>> +    /* clear work counters since we have the values we need */
>> +    ring_container->total_bytes = 0;
>> +    ring_container->total_packets = 0;
>> +
>> +    /* write updated itr to ring container */
>> +    ring_container->itr = itrval;
>> +}
>> +
>> +static void igc_ring_irq_enable(struct igc_q_vector *q_vector)
>> +{
>> +    struct igc_adapter *adapter = q_vector->adapter;
>> +    struct e1000_hw *hw = &adapter->hw;
>> +
>> +    if ((q_vector->rx.ring && (adapter->rx_itr_setting & 3)) ||
>> +        (!q_vector->rx.ring && (adapter->tx_itr_setting & 3))) {
>> +        if (adapter->num_q_vectors == 1)
>> +            igc_set_itr(q_vector);
>> +        else
>> +            igc_update_ring_itr(q_vector);
>> +    }
>> +
>> +    if (!test_bit(__IGC_DOWN, &adapter->state)) {
>> +        if (adapter->msix_entries)
>> +            wr32(E1000_EIMS, q_vector->eims_value);
>> +        else
>> +            igc_irq_enable(adapter);
>> +    }
>> +}
>> +
>> +static void igc_set_itr(struct igc_q_vector *q_vector)
>> +{
>> +    struct igc_adapter *adapter = q_vector->adapter;
>> +    u32 new_itr = q_vector->itr_val;
>> +    u8 current_itr = 0;
>> +
>> +    /* for non-gigabit speeds, just fix the interrupt rate at 4000 */
>> +    switch (adapter->link_speed) {
>> +    case SPEED_10:
>> +    case SPEED_100:
>> +        current_itr = 0;
>> +        new_itr = IGC_4K_ITR;
>> +        goto set_itr_now;
>> +    default:
>> +        break;
>> +    }
>> +
>> +    igc_update_itr(q_vector, &q_vector->tx);
>> +    igc_update_itr(q_vector, &q_vector->rx);
>> +
>> +    current_itr = max(q_vector->rx.itr, q_vector->tx.itr);
>> +
>> +    /* conservative mode (itr 3) eliminates the lowest_latency 
>> setting */
>> +    if (current_itr == lowest_latency &&
>> +        ((q_vector->rx.ring && adapter->rx_itr_setting == 3) ||
>> +        (!q_vector->rx.ring && adapter->tx_itr_setting == 3)))
>> +        current_itr = low_latency;
>> +
>> +    switch (current_itr) {
>> +    /* counts and packets in update_itr are dependent on these 
>> numbers */
>> +    case lowest_latency:
>> +        new_itr = IGC_70K_ITR; /* 70,000 ints/sec */
>> +        break;
>> +    case low_latency:
>> +        new_itr = IGC_20K_ITR; /* 20,000 ints/sec */
>> +        break;
>> +    case bulk_latency:
>> +        new_itr = IGC_4K_ITR;  /* 4,000 ints/sec */
>> +        break;
>> +    default:
>> +        break;
>> +    }
>> +
>> +set_itr_now:
>> +    if (new_itr != q_vector->itr_val) {
>> +        /* this attempts to bias the interrupt rate towards Bulk
>> +         * by adding intermediate steps when interrupt rate is
>> +         * increasing
>> +         */
>> +        new_itr = new_itr > q_vector->itr_val ?
>> +              max((new_itr * q_vector->itr_val) /
>> +              (new_itr + (q_vector->itr_val >> 2)),
>> +              new_itr) : new_itr;
>> +        /* Don't write the value here; it resets the adapter's
>> +         * internal timer, and causes us to delay far longer than
>> +         * we should between interrupts.  Instead, we write the ITR
>> +         * value at the beginning of the next interrupt so the timing
>> +         * ends up being correct.
>> +         */
>> +        q_vector->itr_val = new_itr;
>> +        q_vector->set_itr = 1;
>> +    }
>> +}
>> +
>> +/**
>> + *  igc_poll - NAPI Rx polling callback
>> + *  @napi: napi polling structure
>> + *  @budget: count of how many packets we should handle
>> + **/
>> +static int igc_poll(struct napi_struct *napi, int budget)
>> +{
>> +    struct igc_q_vector *q_vector = container_of(napi,
>> +                             struct igc_q_vector,
>> +                             napi);
>> +    bool clean_complete = true;
>> +    int work_done = 0;
>> +    int cleaned = 0;
>> +
>> +    /* TODO q->vector->tx_ring: igc_clean_tx_irq */
>> +
>> +    if (q_vector->rx.ring) {
>> +        /* TODO igc_clean_rx_irq */
>> +
>> +        work_done += cleaned;
>> +        if (cleaned >= budget)
>> +            clean_complete = false;
>> +    }
>> +
>> +    /* If all work not completed, return budget and keep polling */
>> +    if (!clean_complete)
>> +        return budget;
>> +
>> +    /* If not enough Rx work done, exit the polling mode */
>> +    napi_complete_done(napi, work_done);
>> +    igc_ring_irq_enable(q_vector);
>> +
>> +    return 0;
>> +}
>> +
>> +/**
>> + *  igc_set_interrupt_capability - set MSI or MSI-X if supported
>> + *  @adapter: Pointer to adapter structure
>> + *
>> + *  Attempt to configure interrupts using the best available
>> + *  capabilities of the hardware and kernel.
>> + **/
>> +static void igc_set_interrupt_capability(struct igc_adapter *adapter,
>> +                     bool msix)
>> +{
>> +    int err;
>> +    int numvecs, i;
>> +
>> +    if (!msix)
>> +        goto msi_only;
>> +    adapter->flags |= IGC_FLAG_HAS_MSIX;
>> +
>> +    /* Number of supported queues. */
>> +    adapter->num_rx_queues = adapter->rss_queues;
>> +
>> +    adapter->num_tx_queues = adapter->rss_queues;
>> +
>> +    /* start with one vector for every Rx queue */
>> +    numvecs = adapter->num_rx_queues;
>> +
>> +    /* if Tx handler is separate add 1 for every Tx queue */
>> +    if (!(adapter->flags & IGC_FLAG_QUEUE_PAIRS))
>> +        numvecs += adapter->num_tx_queues;
>> +
>> +    /* store the number of vectors reserved for queues */
>> +    adapter->num_q_vectors = numvecs;
>> +
>> +    /* add 1 vector for link status interrupts */
>> +    numvecs++;
>> +
>> +    adapter->msix_entries = kcalloc(numvecs, sizeof(struct msix_entry),
>> +                    GFP_KERNEL);
>> +
>> +    if (!adapter->msix_entries)
>> +        return;
>> +
>> +    /*populate entry values*/
>> +    for (i = 0; i < numvecs; i++)
>> +        adapter->msix_entries[i].entry = i;
>> +
>> +    err = pci_enable_msix_range(adapter->pdev,
>> +                    adapter->msix_entries,
>> +                    numvecs,
>> +                    numvecs);
> 
> Since you have no flexibility here, use pci_enable_msix_exact() instead.
> 
>> +    if (err > 0)
>> +        return;
>> +
>> +    kfree(adapter->msix_entries);
>> +    adapter->msix_entries = NULL;
>> +
>> +    igc_reset_interrupt_capability(adapter);
>> +
>> +msi_only:
>> +    adapter->flags &= ~IGC_FLAG_HAS_MSIX;
>> +
>> +    adapter->rss_queues = 1;
>> +    adapter->flags |= IGC_FLAG_QUEUE_PAIRS;
>> +    adapter->num_rx_queues = 1;
>> +    adapter->num_tx_queues = 1;
>> +    adapter->num_q_vectors = 1;
>> +    if (!pci_enable_msi(adapter->pdev))
>> +        adapter->flags |= IGC_FLAG_HAS_MSI;
>> +}
>> +
>> +static void igc_add_ring(struct igc_ring *ring,
>> +             struct igc_ring_container *head)
>> +{
>> +    head->ring = ring;
>> +    head->count++;
>> +}
>> +
>> +/**
>> + *  igc_alloc_q_vector - Allocate memory for a single interrupt vector
>> + *  @adapter: board private structure to initialize
>> + *  @v_count: q_vectors allocated on adapter, used for ring interleaving
>> + *  @v_idx: index of vector in adapter struct
>> + *  @txr_count: total number of Tx rings to allocate
>> + *  @txr_idx: index of first Tx ring to allocate
>> + *  @rxr_count: total number of Rx rings to allocate
>> + *  @rxr_idx: index of first Rx ring to allocate
>> + *
>> + *  We allocate one q_vector.  If allocation fails we return -ENOMEM.
>> + **/
>> +static int igc_alloc_q_vector(struct igc_adapter *adapter,
>> +                  unsigned int v_count, unsigned int v_idx,
>> +                  unsigned int txr_count, unsigned int txr_idx,
>> +                  unsigned int rxr_count, unsigned int rxr_idx)
>> +{
>> +    struct igc_q_vector *q_vector;
>> +    struct igc_ring *ring;
>> +    int ring_count, size;
>> +
>> +    /* igc only supports 1 Tx and/or 1 Rx queue per vector */
>> +    if (txr_count > 1 || rxr_count > 1)
>> +        return -ENOMEM;
>> +
>> +    ring_count = txr_count + rxr_count;
>> +    size = sizeof(struct igc_q_vector) +
>> +        (sizeof(struct igc_ring) * ring_count);
>> +
>> +    /* allocate q_vector and rings */
>> +    q_vector = adapter->q_vector[v_idx];
>> +    if (!q_vector)
>> +        q_vector = kzalloc(size, GFP_KERNEL);
>> +    else
>> +        memset(q_vector, 0, size);
>> +    if (!q_vector)
>> +        return -ENOMEM;
>> +
>> +    /* initialize NAPI */
>> +    netif_napi_add(adapter->netdev, &q_vector->napi,
>> +               igc_poll, 64);
>> +
>> +    /* tie q_vector and adapter together */
>> +    adapter->q_vector[v_idx] = q_vector;
>> +    q_vector->adapter = adapter;
>> +
>> +    /* initialize work limits */
>> +    q_vector->tx.work_limit = adapter->tx_work_limit;
>> +
>> +    /* initialize ITR configuration */
>> +    q_vector->itr_register = adapter->io_addr + E1000_EITR(0);
>> +    q_vector->itr_val = IGC_START_ITR;
>> +
>> +    /* initialize pointer to rings */
>> +    ring = q_vector->ring;
>> +
>> +    /* initialize ITR */
>> +    if (rxr_count) {
>> +        /* rx or rx/tx vector */
>> +        if (!adapter->rx_itr_setting || adapter->rx_itr_setting > 3)
>> +            q_vector->itr_val = adapter->rx_itr_setting;
>> +    } else {
>> +        /* tx only vector */
>> +        if (!adapter->tx_itr_setting || adapter->tx_itr_setting > 3)
>> +            q_vector->itr_val = adapter->tx_itr_setting;
>> +    }
>> +
>> +    if (txr_count) {
>> +        /* assign generic ring traits */
>> +        ring->dev = &adapter->pdev->dev;
>> +        ring->netdev = adapter->netdev;
>> +
>> +        /* configure backlink on ring */
>> +        ring->q_vector = q_vector;
>> +
>> +        /* update q_vector Tx values */
>> +        igc_add_ring(ring, &q_vector->tx);
>> +
>> +        /* apply Tx specific ring traits */
>> +        ring->count = adapter->tx_ring_count;
>> +        ring->queue_index = txr_idx;
>> +
>> +        /* assign ring to adapter */
>> +        adapter->tx_ring[txr_idx] = ring;
>> +
>> +        /* push pointer to next ring */
>> +        ring++;
>> +    }
>> +
>> +    if (rxr_count) {
>> +        /* assign generic ring traits */
>> +        ring->dev = &adapter->pdev->dev;
>> +        ring->netdev = adapter->netdev;
>> +
>> +        /* configure backlink on ring */
>> +        ring->q_vector = q_vector;
>> +
>> +        /* update q_vector Rx values */
>> +        igc_add_ring(ring, &q_vector->rx);
>> +
>> +        /* apply Rx specific ring traits */
>> +        ring->count = adapter->rx_ring_count;
>> +        ring->queue_index = rxr_idx;
>> +
>> +        /* assign ring to adapter */
>> +        adapter->rx_ring[rxr_idx] = ring;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +/**
>> + *  igc_alloc_q_vectors - Allocate memory for interrupt vectors
>> + *  @adapter: board private structure to initialize
>> + *
>> + *  We allocate one q_vector per queue interrupt.  If allocation 
>> fails we
>> + *  return -ENOMEM.
>> + **/
>> +static int igc_alloc_q_vectors(struct igc_adapter *adapter)
>> +{
>> +    int q_vectors = adapter->num_q_vectors;
>> +    int rxr_remaining = adapter->num_rx_queues;
>> +    int txr_remaining = adapter->num_tx_queues;
>> +    int rxr_idx = 0, txr_idx = 0, v_idx = 0;
>> +    int err;
> 
> reverse xmas tree
> 
good. fix will be applied in v4.
>> +
>> +    if (q_vectors >= (rxr_remaining + txr_remaining)) {
>> +        for (; rxr_remaining; v_idx++) {
>> +            err = igc_alloc_q_vector(adapter, q_vectors, v_idx,
>> +                         0, 0, 1, rxr_idx);
>> +
>> +        if (err)
>> +            goto err_out;
>> +
>> +        /* update counts and index */
>> +        rxr_remaining--;
>> +        rxr_idx++;
>> +        }
> 
> There's something funky in your indent here.
> 
Good catch,thanks. fix will be applied in v4.
>> +    }
>> +
>> +    for (; v_idx < q_vectors; v_idx++) {
>> +        int rqpv = DIV_ROUND_UP(rxr_remaining, q_vectors - v_idx);
>> +        int tqpv = DIV_ROUND_UP(txr_remaining, q_vectors - v_idx);
>> +
>> +        err = igc_alloc_q_vector(adapter, q_vectors, v_idx,
>> +                     tqpv, txr_idx, rqpv, rxr_idx);
>> +
>> +        if (err)
>> +            goto err_out;
>> +
>> +        /* update counts and index */
>> +        rxr_remaining -= rqpv;
>> +        txr_remaining -= tqpv;
>> +        rxr_idx++;
>> +        txr_idx++;
>> +    }
>> +
>> +    return 0;
>> +
>> +err_out:
>> +    adapter->num_tx_queues = 0;
>> +    adapter->num_rx_queues = 0;
>> +    adapter->num_q_vectors = 0;
>> +
>> +    while (v_idx--)
>> +        igc_free_q_vector(adapter, v_idx);
>> +
>> +    return -ENOMEM;
>> +}
>> +
>> +/**
>> + *  igc_init_interrupt_scheme - initialize interrupts, allocate 
>> queues/vectors
>> + *  @adapter: Pointer to adapter structure
>> + *
>> + *  This function initializes the interrupts and allocates all of the 
>> queues.
>> + **/
>> +static int igc_init_interrupt_scheme(struct igc_adapter *adapter, 
>> bool msix)
>> +{
>> +    struct pci_dev *pdev = adapter->pdev;
>> +    int err = 0;
>> +
>> +    igc_set_interrupt_capability(adapter, msix);
>> +
>> +    err = igc_alloc_q_vectors(adapter);
>> +    if (err) {
>> +        dev_err(&pdev->dev, "Unable to allocate memory for vectors\n");
>> +        goto err_alloc_q_vectors;
>> +    }
>> +
>> +    /* TODO complete igc_cache_ring_register */
>> +
>> +    return 0;
>> +
>> +err_alloc_q_vectors:
>> +    igc_reset_interrupt_capability(adapter);
>> +    return err;
>> +}
>> +
>> +static void igc_free_irq(struct igc_adapter *adapter)
>> +{
>> +    if (adapter->msix_entries) {
>> +        int vector = 0, i;
>> +
>> +    free_irq(adapter->msix_entries[vector++].vector, adapter);
>> +
>> +    for (i = 0; i < adapter->num_q_vectors; i++)
>> +        free_irq(adapter->msix_entries[vector++].vector,
>> +             adapter->q_vector[i]);
> 
> Check your indent and {}'s
> 
Good catch, thanks. fix will be applied to v4.
>> +    } else {
>> +        free_irq(adapter->pdev->irq, adapter);
>> +    }
>> +}
>> +
>> +/**
>> + *  igc_irq_disable - Mask off interrupt generation on the NIC
>> + *  @adapter: board private structure
>> + **/
>> +static void igc_irq_disable(struct igc_adapter *adapter)
>> +{
>> +    struct e1000_hw *hw = &adapter->hw;
>> +
>> +    if (adapter->msix_entries) {
>> +        u32 regval = rd32(E1000_EIAM);
>> +
>> +        wr32(E1000_EIAM, regval & ~adapter->eims_enable_mask);
>> +        wr32(E1000_EIMC, adapter->eims_enable_mask);
>> +        regval = rd32(E1000_EIAC);
>> +        wr32(E1000_EIAC, regval & ~adapter->eims_enable_mask);
>> +    }
>> +
>> +    wr32(E1000_IAM, 0);
>> +    wr32(E1000_IMC, ~0);
>> +    wrfl();
>> +
>> +    if (adapter->msix_entries) {
>> +        int vector = 0, i;
>> +
>> +        synchronize_irq(adapter->msix_entries[vector++].vector);
>> +
>> +        for (i = 0; i < adapter->num_q_vectors; i++)
>> +            synchronize_irq(adapter->msix_entries[vector++].vector);
>> +    } else {
>> +        synchronize_irq(adapter->pdev->irq);
>> +    }
>> +}
>> +
>> +/**
>> + *  igc_irq_enable - Enable default interrupt generation settings
>> + *  @adapter: board private structure
>> + **/
>> +static void igc_irq_enable(struct igc_adapter *adapter)
>> +{
>> +    struct e1000_hw *hw = &adapter->hw;
>> +
>> +    if (adapter->msix_entries) {
>> +        u32 ims = E1000_IMS_LSC | E1000_IMS_DOUTSYNC | E1000_IMS_DRSTA;
>> +        u32 regval = rd32(E1000_EIAC);
>> +
>> +        wr32(E1000_EIAC, regval | adapter->eims_enable_mask);
>> +        regval = rd32(E1000_EIAM);
>> +        wr32(E1000_EIAM, regval | adapter->eims_enable_mask);
>> +        wr32(E1000_EIMS, adapter->eims_enable_mask);
>> +        wr32(E1000_IMS, ims);
>> +    } else {
>> +        wr32(E1000_IMS, IMS_ENABLE_MASK | E1000_IMS_DRSTA);
>> +        wr32(E1000_IAM, IMS_ENABLE_MASK | E1000_IMS_DRSTA);
>> +    }
>> +}
>> +
>> +/**
>> + *  igc_request_irq - initialize interrupts
>> + *  @adapter: Pointer to adapter structure
>> + *
>> + *  Attempts to configure interrupts using the best available
>> + *  capabilities of the hardware and kernel.
>> + **/
>> +static int igc_request_irq(struct igc_adapter *adapter)
>> +{
>> +    int err = 0;
>> +
>> +    if (adapter->flags & IGC_FLAG_HAS_MSIX) {
>> +        err = igc_request_msix(adapter);
>> +        if (!err)
>> +            goto request_done;
>> +        /* fall back to MSI */
>> +        /* TODO complete free tx/rx resources */
>> +
>> +        igc_clear_interrupt_scheme(adapter);
>> +        err = igc_init_interrupt_scheme(adapter, false);
>> +        if (err)
>> +            goto request_done;
>> +        /* TODO complete setup tx/rx resources */
>> +        igc_configure(adapter);
>> +    }
>> +
>> +request_done:
>> +    return err;
>> +}
>> +
>> +static irqreturn_t igc_msix_ring(int irq, void *data)
>> +{
>> +    struct igc_q_vector *q_vector = data;
>> +
>> +    /* Write the ITR value calculated from the previous interrupt. */
>> +    igc_write_itr(q_vector);
>> +
>> +    napi_schedule(&q_vector->napi);
>> +
>> +    return IRQ_HANDLED;
>> +}
>> +
>> +static void igc_write_itr(struct igc_q_vector *q_vector)
>> +{
>> +    u32 itr_val = q_vector->itr_val & 0x7FFC;
> 
> Can we use a #define for this mask value?
> 
>> +
>> +    if (!q_vector->set_itr)
>> +        return;
>> +
>> +    if (!itr_val)
>> +        itr_val = 0x4;
> 
> It would be nice to have these values as named #defines as well, or 
> enums... whatever.
> 
>> +
>> +    itr_val |= E1000_EITR_CNT_IGNR;
>> +
>> +    writel(itr_val, q_vector->itr_register);
>> +    q_vector->set_itr = 0;
>> +}
>> +
>> +/**
>> + *  igc_open - Called when a network interface is made active
>> + *  @netdev: network interface device structure
>> + *
>> + *  Returns 0 on success, negative value on failure
>> + *
>> + *  The open entry point is called when a network interface is made
>> + *  active by the system (IFF_UP).  At this point all resources needed
>> + *  for transmit and receive operations are allocated, the interrupt
>> + *  handler is registered with the OS, the watchdog timer is started,
>> + *  and the stack is notified that the interface is ready.
>>    **/
>>   static int __igc_open(struct net_device *netdev, bool resuming)
>>   {
>>       struct igc_adapter *adapter = netdev_priv(netdev);
>>       struct e1000_hw *hw = &adapter->hw;
>>       int i = 0;
>> +    int err = 0;
> 
> reverse xmas tree
> 
good. fix will be applied in v4.
>>       /* disallow open during test */
>> @@ -334,17 +1336,41 @@ static int __igc_open(struct net_device 
>> *netdev, bool resuming)
>>       igc_configure(adapter);
>> +    err = igc_request_irq(adapter);
>> +    if (err)
>> +        goto err_req_irq;
>> +
>> +    /* Notify the stack of the actual queue counts. */
>> +    netif_set_real_num_tx_queues(netdev, adapter->num_tx_queues);
> 
> Perhaps you can check for a possible error return here as you do for the 
> next line?
> 
>> +
>> +    err = netif_set_real_num_rx_queues(netdev, adapter->num_rx_queues);
>> +    if (err)
>> +        goto err_set_queues;
>> +
>>       /* From here on the code is the same as igc_up() */
>>       clear_bit(__IGC_DOWN, &adapter->state);
>>       for (i = 0; i < adapter->num_q_vectors; i++)
>>           napi_enable(&adapter->q_vector[i]->napi);
>> +    /* Clear any pending interrupts. */
>> +    rd32(E1000_ICR);
>> +    igc_irq_enable(adapter);
>> +
>>       /* start the watchdog. */
>>       hw->mac.get_link_status = 1;
>>       schedule_work(&adapter->watchdog_task);
>>       return E1000_SUCCESS;
>> +
>> +err_set_queues:
>> +    igc_free_irq(adapter);
>> +err_req_irq:
>> +    igc_release_hw_control(adapter);
>> +    igc_power_down_link(adapter);
>> +    /* TODO complete free_all_rx_resources */
>> +
>> +    return err;
>>   }
>>   int igc_open(struct net_device *netdev)
>> @@ -353,15 +1379,15 @@ int igc_open(struct net_device *netdev)
>>   }
>>   /**
>> - * igc_close - Disables a network interface
>> - * @netdev: network interface device structure
>> + *  igc_close - Disables a network interface
>> + *  @netdev: network interface device structure
>>    *
>> - * Returns 0, this is not allowed to fail
>> + *  Returns 0, this is not allowed to fail
>>    *
>> - * The close entry point is called when an interface is de-activated
>> - * by the OS.  The hardware is still under the driver's control, but
>> - * needs to be disabled.  A global MAC reset is issued to stop the
>> - * hardware, and all transmit and receive resources are freed.
>> + *  The close entry point is called when an interface is de-activated
>> + *  by the OS.  The hardware is still under the driver's control, but
>> + *  needs to be disabled.  A global MAC reset is issued to stop the
>> + *  hardware, and all transmit and receive resources are freed.
>>    **/
>>   static int __igc_close(struct net_device *netdev, bool suspending)
>>   {
>> @@ -373,6 +1399,8 @@ static int __igc_close(struct net_device *netdev, 
>> bool suspending)
>>       igc_release_hw_control(adapter);
>> +    igc_free_irq(adapter);
>> +
>>       return 0;
>>   }
>> @@ -605,6 +1633,8 @@ static int igc_probe(struct pci_dev *pdev,
>>   err_register:
>>       igc_release_hw_control(adapter);
>>   err_sw_init:
>> +    igc_clear_interrupt_scheme(adapter);
>> +    iounmap(adapter->io_addr);
>>   err_ioremap:
>>       free_netdev(netdev);
>>   err_alloc_etherdev:
>> @@ -682,6 +1712,14 @@ static int igc_sw_init(struct igc_adapter *adapter)
>>       adapter->max_frame_size = netdev->mtu + ETH_HLEN + ETH_FCS_LEN +
>>                       VLAN_HLEN;
>> +    if (igc_init_interrupt_scheme(adapter, true)) {
>> +        dev_err(&pdev->dev, "Unable to allocate memory for queues\n");
>> +        return -ENOMEM;
>> +    }
>> +
>> +    /* Explicitly disable IRQ since the NIC can be in any state. */
>> +    igc_irq_disable(adapter);
>> +
>>       set_bit(__IGC_DOWN, &adapter->state);
>>       return 0;
>>
address part (nine,9) of comments.


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