On Thu, 21 Oct 2010, Andy Cress wrote:
> My kernel configuration had CONFIG_PREEMPT=y, and the ixgbe 3.0.12
> module produced the following error message when it was loaded.
> BUG: using smp_processor_id() in preemptible [00000000] code:
> Below is a patch that works for me to resolve this. Please review it.
>
this patch is not necessary for any production kernel.org kernels. I'm
not sure what kernel you're running, but maybe they have changed
include/linux/smp.h for some reason to change get_cpu.
All get_cpu calls defined include a preempt_disable that I can see.
one other option is that our kcompat code tries to work around kernels
without get_cpu, could that be the issue?
does your kernel not implement the LINUX_VERSION_CODE macro?
our code has this which could trigger an override of get_cpu
#if ( LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) )
#undef get_cpu
#define get_cpu() smp_processor_id()
#undef put_cpu
#define put_cpu() do { } while(0)
but that should only be in effect for kernels < 2.6 (aka 2.4.X kernels)
I suggest putting a #warning in the macro above and see if you hit it.
> Andy
>
> Signed-off-by: cress <[email protected]>
> ---
> drivers/net/ixgbe/ixgbe_main.c | 22 ++++++++++++++++------
> 1 files changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_main.c
> b/drivers/net/ixgbe/ixgbe_main.c
> index 25135fe..e89f5b6 100644
> --- a/drivers/net/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ixgbe/ixgbe_main.c
> @@ -677,10 +677,12 @@ static void ixgbe_update_tx_dca(struct
> ixgbe_adapter *adapter,
> static void ixgbe_update_dca(struct ixgbe_q_vector *q_vector)
> {
> struct ixgbe_adapter *adapter = q_vector->adapter;
> - int cpu = get_cpu();
> + int cpu;
> long r_idx;
> int i;
>
> + preempt_disable();
> + cpu = smp_processor_id(); /*same as get_cpu()*/
> if (q_vector->cpu == cpu)
> goto out_no_update;
>
> @@ -701,6 +703,7 @@ static void ixgbe_update_dca(struct ixgbe_q_vector
> *q_vector)
> q_vector->cpu = cpu;
> out_no_update:
> put_cpu();
> + preempt_enable();
> }
>
> static void ixgbe_setup_dca(struct ixgbe_adapter *adapter)
> @@ -8015,7 +8018,10 @@ static void ixgbe_netpoll(struct net_device
> *netdev)
> static u16 ixgbe_select_queue(struct net_device *dev, struct sk_buff
> *skb)
> {
> struct ixgbe_adapter *adapter = netdev_priv(dev);
> - int txq = smp_processor_id();
> + int txq;
> +
> + preempt_disable();
> + txq = smp_processor_id();
>
> #ifdef IXGBE_FCOE
> if ((skb->protocol == __constant_htons(ETH_P_FCOE)) ||
> @@ -8023,10 +8029,10 @@ static u16 ixgbe_select_queue(struct net_device
> *dev, struct sk_buff *skb)
> if (adapter->flags & IXGBE_FLAG_FCOE_ENABLED) {
> txq &=
> (adapter->ring_feature[RING_F_FCOE].indices - 1);
> txq += adapter->ring_feature[RING_F_FCOE].mask;
> - return txq;
> + goto out_txq;
> } else if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
> txq = adapter->fcoe.up;
> - return txq;
> + goto out_txq;
> }
> }
>
> @@ -8034,7 +8040,7 @@ static u16 ixgbe_select_queue(struct net_device
> *dev, struct sk_buff *skb)
> if (adapter->flags & IXGBE_FLAG_FDIR_HASH_CAPABLE) {
> while (unlikely(txq >= dev->real_num_tx_queues))
> txq -= dev->real_num_tx_queues;
> - return txq;
> + goto out_txq;
> }
>
> if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
> @@ -8043,9 +8049,13 @@ static u16 ixgbe_select_queue(struct net_device
> *dev, struct sk_buff *skb)
> else
> txq = (skb->vlan_tci &
> IXGBE_TX_FLAGS_VLAN_PRIO_MASK)
> >> 13;
> - return txq;
> + goto out_txq;
> }
> + preempt_enable();
> return skb_tx_hash(dev, skb);
> +out_txq:
> + preempt_enable();
> + return txq;
> }
>
> #endif /* HAVE_NETDEV_SELECT_QUEUE */
>
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