Re: [PATCH] Make netif_rx_ni preempt-safe

[Denis Vlasenko <vda@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

> How about this:
> 
> Signed-Off-By: Lee Revell <rlrevell@xxxxxxxxxxx>
> 
> --- include/linux/netdevice.h~        2004-10-19 20:16:48.000000000 -0400
> +++ include/linux/netdevice.h 2004-10-19 20:21:01.000000000 -0400
> @@ -696,9 +696,12 @@
>   */
>  static inline int netif_rx_ni(struct sk_buff *skb)
>  {
> -       int err = netif_rx(skb);
> +       int err;
> +       preempt_disable();
> +       err = netif_rx(skb);
>         if (softirq_pending(smp_processor_id()))
>                 do_softirq();
> +       preempt_enable();
>         return err;
>  }

#include <linux/netdevice.h>

int netif_rx_ni_(struct sk_buff *skb)
{
    int err;
    preempt_disable();
    err = netif_rx(skb);
    if (softirq_pending(smp_processor_id()))
        do_softirq();
    preempt_enable();
    return err;
}

objdump -d:
00000000 <netif_rx_ni_>:
   0:   55                      push   %ebp
   1:   89 e5                   mov    %esp,%ebp
   3:   56                      push   %esi
   4:   53                      push   %ebx
   5:   bb 00 f0 ff ff          mov    $0xfffff000,%ebx
   a:   21 e3                   and    %esp,%ebx
   c:   ff 43 14                incl   0x14(%ebx)
   f:   8b 4d 08                mov    0x8(%ebp),%ecx
  12:   51                      push   %ecx
  13:   e8 fc ff ff ff          call   14 <netif_rx_ni_+0x14>
  18:   89 c6                   mov    %eax,%esi
  1a:   8b 43 10                mov    0x10(%ebx),%eax
  1d:   c1 e0 07                shl    $0x7,%eax
  20:   8b 80 00 00 00 00       mov    0x0(%eax),%eax
  26:   85 c0                   test   %eax,%eax
  28:   5a                      pop    %edx
  29:   75 25                   jne    50 <netif_rx_ni_+0x50>
  2b:   8b 43 08                mov    0x8(%ebx),%eax
  2e:   ff 4b 14                decl   0x14(%ebx)
  31:   a8 08                   test   $0x8,%al
  33:   75 09                   jne    3e <netif_rx_ni_+0x3e>
  35:   8d 65 f8                lea    0xfffffff8(%ebp),%esp
  38:   5b                      pop    %ebx
  39:   89 f0                   mov    %esi,%eax
  3b:   5e                      pop    %esi
  3c:   5d                      pop    %ebp
  3d:   c3                      ret
  3e:   e8 fc ff ff ff          call   3f <netif_rx_ni_+0x3f>
  43:   eb f0                   jmp    35 <netif_rx_ni_+0x35>
  45:   8d 74 26 00             lea    0x0(%esi,1),%esi
  49:   8d bc 27 00 00 00 00    lea    0x0(%edi,1),%edi
  50:   e8 fc ff ff ff          call   51 <netif_rx_ni_+0x51>
  55:   eb d4                   jmp    2b <netif_rx_ni_+0x2b>

0x57 == 87 bytes is too big for inline.
--
vda