Regarding wrong usage of spin_lock_bh

[Mohammed Shafi]

Hi,

probably taking two consecutive spin_lock_bh ?
spin_lock_bh(a)
spin_lock_bh(b)

any thoughts, would be appreciated.

thanks,
shafi


On Thu, Aug 8, 2013 at 1:01 PM, Mohammed Shafi <shafi.kernel at gmail.com>wrote:

> Hi,
>
> I see a warning,
>
> /qsdk/qca/src/linux/kernel/softirq.c:159 local_bh_enable_ip+0x5c/0xe0()
>
> spin_lock_bh. While dev_ioctl is called from user context, not sure
> why we have the warning because of the following reasons in softirq.c :
> 159
>
> 1. in_irqs - interrupt handler context           (So we need to use
> spin_lock_irq_save )
> 2. disabled_irqs - interrupts are disabled    (spin_lock should be good
> enough ).
>
> Can some one give me more thoughts, I can see that its not necessary to
> call spin_lock_bh
> from softirq context, what are the other scenarios where this might be a
> problem or not
> necessary ?  The above warning comes from dev_ioctl  (user context), when
> a new
> network interface is added.
>
> thanks,
> shafi
>
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