Re: [PATCH] spinlock: rm duplicated preempt en/disable for bottomhalf

[Eric Dumazet]

Le mardi 27 septembre 2011 Ã 17:40 +0800, Bob Liu a Ãcrit :
> On Tue, Sep 27, 2011 at 5:13 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > On Tue, 2011-09-27 at 15:56 +0800, Bob Liu wrote:
> >> local_bh_en/disable() has already deal with en/disable preempt, so rm the
> >> dumplicated one from spinlock_api_up/smp.h head file.
> >
> > I bet you haven't tried booting this..  you just broke stuff like:
> >
> 
> I only tried it on blackfin arch and can boot successfully
> although it's a simple single-cpu ystem.
> 
> >  spin_lock_bh(&foo);
> >  /* do crap */
> >  spin_unlock(&foo);
> >  /* do some other crap */
> >  local_bh_enable();
> >
> >
> > And yes that does happen.
> 
> Could you please give an example?  I did a simple search but no result.
> I thought the user should use spin_lock_bh()/spin_unlock_bh() in pairs.
> 

You probably can find such use in network stack.

net/ipv4/inet_hashtables.c  function  __inet_hash_connect()



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