On 16-08-28 08:56 AM, William Tu wrote:
> Hi,
>
> Reading through the patch, I found some minor typos below.
>
> On Sat, Aug 27, 2016 at 12:11 AM, John Fastabend
> <john.fastab...@gmail.com> wrote:
>> From: Alexei Starovoitov <a...@fb.com>
>>
>> This patch adds initial support for XDP on e1000 driver. Note e1000
>> driver does not support page recycling in general which could be
>> added as a further improvement. However for XDP_DROP and XDP_XMIT
>
> I think you mean XDP_PASS instead of XDP_XMIT?
>
I really meant XDP_TX but see Or's note and next revision will have
XDP_DROP only here.
>> the xdp code paths will recycle pages.
>>
>> This patch includes the rcu_read_lock/rcu_read_unlock pair noted by
>> Brenden Blanco in another pending patch.
>>
>> net/mlx4_en: protect ring->xdp_prog with rcu_read_lock
>>
>> CC: William Tu <u9012...@gmail.com>
>> Signed-off-by: Alexei Starovoitov <a...@kernel.org>
>> Signed-off-by: John Fastabend <john.r.fastab...@intel.com>
>> ---
>> drivers/net/ethernet/intel/e1000/e1000.h | 1
>> drivers/net/ethernet/intel/e1000/e1000_main.c | 168
>> ++++++++++++++++++++++++-
>> 2 files changed, 165 insertions(+), 4 deletions(-)
>>
>> +static void e1000_xmit_raw_frame(struct e1000_rx_buffer *rx_buffer_info,
>> + unsigned int len,
>> + struct net_device *netdev,
>> + struct e1000_adapter *adapter)
>> +{
>> + struct netdev_queue *txq = netdev_get_tx_queue(netdev, 0);
>> + struct e1000_hw *hw = &adapter->hw;
>> + struct e1000_tx_ring *tx_ring;
>> +
>> + if (len > E1000_MAX_DATA_PER_TXD)
>> + return;
>> +
>> + /* e1000 only support a single txq at the moment so the queue is
>> being
>> + * shared with stack. To support this requires locking to ensure the
>> + * stack and XPD are not running at the same time. Devices would
>> + * multiple queues should allocate a separate queue space.
>> + */
>
> XPD --> XDP
> Devices would --> with?
Yep typo.
>
>> + HARD_TX_LOCK(netdev, txq, smp_processor_id());
>> +
>> + tx_ring = adapter->tx_ring;
>> +
>> + if (E1000_DESC_UNUSED(tx_ring) < 2)
>> + return;
>> +
>> + e1000_tx_map_rxpage(tx_ring, rx_buffer_info, len);
>> +
>> + e1000_tx_queue(adapter, tx_ring, 0/*tx_flags*/, 1);
>> +
>> + writel(tx_ring->next_to_use, hw->hw_addr + tx_ring->tdt);
>> + mmiowb();
>> +
>> + HARD_TX_UNLOCK(netdev, txq);
>> +}
>> +
>> #define NUM_REGS 38 /* 1 based count */
>> static void e1000_regdump(struct e1000_adapter *adapter)
>> {
>> @@ -4142,6 +4240,22 @@ static struct sk_buff *e1000_alloc_rx_skb(struct
>> e1000_adapter *adapter,
>> return skb;
>> }
>>
>> +static inline int e1000_call_bpf(struct bpf_prog *prog, void *data,
>> + unsigned int length)
>> +{
>> + struct xdp_buff xdp;
>> + int ret;
>> +
>> + xdp.data = data;
>> + xdp.data_end = data + length;
>> +
>> + rcu_read_lock();
>> + ret = BPF_PROG_RUN(prog, (void *)&xdp);
>> + rcu_read_unlock();
>> +
>> + return ret;
>> +}
>> +
>> /**
>> * e1000_clean_jumbo_rx_irq - Send received data up the network stack;
>> legacy
>> * @adapter: board private structure
>> @@ -4160,12 +4274,15 @@ static bool e1000_clean_jumbo_rx_irq(struct
>> e1000_adapter *adapter,
>> struct pci_dev *pdev = adapter->pdev;
>> struct e1000_rx_desc *rx_desc, *next_rxd;
>> struct e1000_rx_buffer *buffer_info, *next_buffer;
>> + struct bpf_prog *prog;
>> u32 length;
>> unsigned int i;
>> int cleaned_count = 0;
>> bool cleaned = false;
>> unsigned int total_rx_bytes = 0, total_rx_packets = 0;
>>
>> + rcu_read_lock(); /* rcu lock needed here to protect xdp programs */
>> + prog = READ_ONCE(adapter->prog);
>
> If having rcu_read_lock() here, do we still need another in e1000_call_bpf()?
nope good catch. Thanks for the review!
