* [PATCH] spinlock: rm duplicated preempt en/disable for bottom half
@ 2011-09-27 7:56 Bob Liu
2011-09-27 9:13 ` Peter Zijlstra
0 siblings, 1 reply; 4+ messages in thread
From: Bob Liu @ 2011-09-27 7:56 UTC (permalink / raw)
To: linux-kernel; +Cc: mingo, joe, tglx, peterz, Bob Liu
local_bh_en/disable() has already deal with en/disable preempt, so rm the
dumplicated one from spinlock_api_up/smp.h head file.
Signed-off-by: Bob Liu <lliubbo@gmail.com>
---
include/linux/spinlock_api_smp.h | 4 ----
include/linux/spinlock_api_up.h | 5 ++---
2 files changed, 2 insertions(+), 7 deletions(-)
diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h
index e253ccd..ba8b8f3 100644
--- a/include/linux/spinlock_api_smp.h
+++ b/include/linux/spinlock_api_smp.h
@@ -132,7 +132,6 @@ static inline void __raw_spin_lock_irq(raw_spinlock_t *lock)
static inline void __raw_spin_lock_bh(raw_spinlock_t *lock)
{
local_bh_disable();
- preempt_disable();
spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
}
@@ -174,19 +173,16 @@ static inline void __raw_spin_unlock_bh(raw_spinlock_t *lock)
{
spin_release(&lock->dep_map, 1, _RET_IP_);
do_raw_spin_unlock(lock);
- preempt_enable_no_resched();
local_bh_enable_ip((unsigned long)__builtin_return_address(0));
}
static inline int __raw_spin_trylock_bh(raw_spinlock_t *lock)
{
local_bh_disable();
- preempt_disable();
if (do_raw_spin_trylock(lock)) {
spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
return 1;
}
- preempt_enable_no_resched();
local_bh_enable_ip((unsigned long)__builtin_return_address(0));
return 0;
}
diff --git a/include/linux/spinlock_api_up.h b/include/linux/spinlock_api_up.h
index af1f472..c9e4f1c 100644
--- a/include/linux/spinlock_api_up.h
+++ b/include/linux/spinlock_api_up.h
@@ -28,7 +28,7 @@
do { preempt_disable(); __acquire(lock); (void)(lock); } while (0)
#define __LOCK_BH(lock) \
- do { local_bh_disable(); __LOCK(lock); } while (0)
+ do { local_bh_disable(); __acquire(lock); (void)(lock); } while (0)
#define __LOCK_IRQ(lock) \
do { local_irq_disable(); __LOCK(lock); } while (0)
@@ -40,8 +40,7 @@
do { preempt_enable(); __release(lock); (void)(lock); } while (0)
#define __UNLOCK_BH(lock) \
- do { preempt_enable_no_resched(); local_bh_enable(); \
- __release(lock); (void)(lock); } while (0)
+ do { local_bh_enable(); __release(lock); (void)(lock); } while (0)
#define __UNLOCK_IRQ(lock) \
do { local_irq_enable(); __UNLOCK(lock); } while (0)
--
1.6.3.3
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] spinlock: rm duplicated preempt en/disable for bottom half
2011-09-27 7:56 [PATCH] spinlock: rm duplicated preempt en/disable for bottom half Bob Liu
@ 2011-09-27 9:13 ` Peter Zijlstra
2011-09-27 9:40 ` Bob Liu
0 siblings, 1 reply; 4+ messages in thread
From: Peter Zijlstra @ 2011-09-27 9:13 UTC (permalink / raw)
To: Bob Liu; +Cc: linux-kernel, mingo, joe, tglx
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:
spin_lock_bh(&foo);
/* do crap */
spin_unlock(&foo);
/* do some other crap */
local_bh_enable();
And yes that does happen.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] spinlock: rm duplicated preempt en/disable for bottom half
2011-09-27 9:13 ` Peter Zijlstra
@ 2011-09-27 9:40 ` Bob Liu
2011-09-27 9:57 ` Eric Dumazet
0 siblings, 1 reply; 4+ messages in thread
From: Bob Liu @ 2011-09-27 9:40 UTC (permalink / raw)
To: Peter Zijlstra; +Cc: linux-kernel, mingo, joe, tglx
On Tue, Sep 27, 2011 at 5:13 PM, Peter Zijlstra <peterz@infradead.org> 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.
--
Regards,
--Bob
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] spinlock: rm duplicated preempt en/disable for bottom half
2011-09-27 9:40 ` Bob Liu
@ 2011-09-27 9:57 ` Eric Dumazet
0 siblings, 0 replies; 4+ messages in thread
From: Eric Dumazet @ 2011-09-27 9:57 UTC (permalink / raw)
To: Bob Liu; +Cc: Peter Zijlstra, linux-kernel, mingo, joe, tglx
Le mardi 27 septembre 2011 à 17:40 +0800, Bob Liu a écrit :
> On Tue, Sep 27, 2011 at 5:13 PM, Peter Zijlstra <peterz@infradead.org> 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()
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-09-27 9:57 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2011-09-27 7:56 [PATCH] spinlock: rm duplicated preempt en/disable for bottom half Bob Liu
2011-09-27 9:13 ` Peter Zijlstra
2011-09-27 9:40 ` Bob Liu
2011-09-27 9:57 ` Eric Dumazet
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