* [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw spinlock
@ 2012-05-17 10:15 Yong Zhang
2012-05-17 16:30 ` David Daney
0 siblings, 1 reply; 4+ messages in thread
From: Yong Zhang @ 2012-05-17 10:15 UTC (permalink / raw)
To: linux-rt-users, linux-kernel; +Cc: ralf, david.daney, tglx
From: Yong Zhang <yong.zhang@windriver.com>
Because __cpu_disable is called in atomic context and spinlock
is a mutex on -rt.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
---
arch/mips/cavium-octeon/smp.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c
index ef9c34a..473c72b 100644
--- a/arch/mips/cavium-octeon/smp.c
+++ b/arch/mips/cavium-octeon/smp.c
@@ -257,7 +257,7 @@ DEFINE_PER_CPU(int, cpu_state);
extern void fixup_irqs(void);
-static DEFINE_SPINLOCK(smp_reserve_lock);
+static DEFINE_RAW_SPINLOCK(smp_reserve_lock);
static int octeon_cpu_disable(void)
{
@@ -266,7 +266,7 @@ static int octeon_cpu_disable(void)
if (cpu == 0)
return -EBUSY;
- spin_lock(&smp_reserve_lock);
+ raw_spin_lock(&smp_reserve_lock);
set_cpu_online(cpu, false);
cpu_clear(cpu, cpu_callin_map);
@@ -277,7 +277,7 @@ static int octeon_cpu_disable(void)
flush_cache_all();
local_flush_tlb_all();
- spin_unlock(&smp_reserve_lock);
+ raw_spin_unlock(&smp_reserve_lock);
return 0;
}
--
1.7.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw spinlock
2012-05-17 10:15 [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw spinlock Yong Zhang
@ 2012-05-17 16:30 ` David Daney
2012-05-17 20:50 ` Ralf Baechle
0 siblings, 1 reply; 4+ messages in thread
From: David Daney @ 2012-05-17 16:30 UTC (permalink / raw)
To: Yong Zhang, ralf; +Cc: linux-rt-users, linux-kernel, david.daney, tglx
On 05/17/2012 03:15 AM, Yong Zhang wrote:
> From: Yong Zhang<yong.zhang@windriver.com>
>
> Because __cpu_disable is called in atomic context and spinlock
> is a mutex on -rt.
>
> Signed-off-by: Yong Zhang<yong.zhang0@gmail.com>
> ---
> arch/mips/cavium-octeon/smp.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c
> index ef9c34a..473c72b 100644
> --- a/arch/mips/cavium-octeon/smp.c
> +++ b/arch/mips/cavium-octeon/smp.c
> @@ -257,7 +257,7 @@ DEFINE_PER_CPU(int, cpu_state);
>
> extern void fixup_irqs(void);
>
> -static DEFINE_SPINLOCK(smp_reserve_lock);
> +static DEFINE_RAW_SPINLOCK(smp_reserve_lock);
>
Ralf added this in 773cb77d (MIPS: Cavium: Add CPU hotplugging code.)
I'm not even sure what this lock is supposed to be protecting, so I
would like Ralf to take a look.
You can add an Acked-by: from me for either this patch as is, or if Ralf
thinks it is OK, removing the lock entirely.
In any event we can merge this via Ralf's tree.
Thanks,
David Daney
> static int octeon_cpu_disable(void)
> {
> @@ -266,7 +266,7 @@ static int octeon_cpu_disable(void)
> if (cpu == 0)
> return -EBUSY;
>
> - spin_lock(&smp_reserve_lock);
> + raw_spin_lock(&smp_reserve_lock);
>
> set_cpu_online(cpu, false);
> cpu_clear(cpu, cpu_callin_map);
> @@ -277,7 +277,7 @@ static int octeon_cpu_disable(void)
> flush_cache_all();
> local_flush_tlb_all();
>
> - spin_unlock(&smp_reserve_lock);
> + raw_spin_unlock(&smp_reserve_lock);
>
> return 0;
> }
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw spinlock
2012-05-17 16:30 ` David Daney
@ 2012-05-17 20:50 ` Ralf Baechle
2012-05-18 2:29 ` Yong Zhang
0 siblings, 1 reply; 4+ messages in thread
From: Ralf Baechle @ 2012-05-17 20:50 UTC (permalink / raw)
To: David Daney; +Cc: Yong Zhang, linux-rt-users, linux-kernel, david.daney, tglx
On Thu, May 17, 2012 at 09:30:42AM -0700, David Daney wrote:
> Date: Thu, 17 May 2012 09:30:42 -0700
> From: David Daney <ddaney.cavm@gmail.com>
> To: Yong Zhang <yong.zhang0@gmail.com>, ralf@linux-mips.org
> CC: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
> david.daney@cavium.com, tglx@linutronix.de
> Subject: Re: [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw
> spinlock
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 05/17/2012 03:15 AM, Yong Zhang wrote:
> >From: Yong Zhang<yong.zhang@windriver.com>
> >
> >Because __cpu_disable is called in atomic context and spinlock
> >is a mutex on -rt.
> >
> >Signed-off-by: Yong Zhang<yong.zhang0@gmail.com>
> >---
> > arch/mips/cavium-octeon/smp.c | 6 +++---
> > 1 files changed, 3 insertions(+), 3 deletions(-)
> >
> >diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c
> >index ef9c34a..473c72b 100644
> >--- a/arch/mips/cavium-octeon/smp.c
> >+++ b/arch/mips/cavium-octeon/smp.c
> >@@ -257,7 +257,7 @@ DEFINE_PER_CPU(int, cpu_state);
> >
> > extern void fixup_irqs(void);
> >
> >-static DEFINE_SPINLOCK(smp_reserve_lock);
> >+static DEFINE_RAW_SPINLOCK(smp_reserve_lock);
> >
>
> Ralf added this in 773cb77d (MIPS: Cavium: Add CPU hotplugging code.)
>
> I'm not even sure what this lock is supposed to be protecting, so I
> would like Ralf to take a look.
>
> You can add an Acked-by: from me for either this patch as is, or if
> Ralf thinks it is OK, removing the lock entirely.
>
> In any event we can merge this via Ralf's tree.
The 773cb77d patch has a long history but I think I first worked on it for
Wind River Linux 2.0 which was 2.6.21-based, then broke it out and pushed
it upstream. In 2.6.21 it was probably infected by the the smp_reserve_lock
virus in the s390 code for no good reason. So I agree, the lock can
be dropped and I'm queueing a patch to do so for 3.5.
Ralf
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw spinlock
2012-05-17 20:50 ` Ralf Baechle
@ 2012-05-18 2:29 ` Yong Zhang
0 siblings, 0 replies; 4+ messages in thread
From: Yong Zhang @ 2012-05-18 2:29 UTC (permalink / raw)
To: Ralf Baechle; +Cc: David Daney, linux-rt-users, linux-kernel, david.daney, tglx
On Thu, May 17, 2012 at 10:50:03PM +0200, Ralf Baechle wrote:
> On Thu, May 17, 2012 at 09:30:42AM -0700, David Daney wrote:
> > Date: Thu, 17 May 2012 09:30:42 -0700
> > From: David Daney <ddaney.cavm@gmail.com>
> > To: Yong Zhang <yong.zhang0@gmail.com>, ralf@linux-mips.org
> > CC: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
> > david.daney@cavium.com, tglx@linutronix.de
> > Subject: Re: [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw
> > spinlock
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > On 05/17/2012 03:15 AM, Yong Zhang wrote:
> > >From: Yong Zhang<yong.zhang@windriver.com>
> > >
> > >Because __cpu_disable is called in atomic context and spinlock
> > >is a mutex on -rt.
> > >
> > >Signed-off-by: Yong Zhang<yong.zhang0@gmail.com>
> > >---
> > > arch/mips/cavium-octeon/smp.c | 6 +++---
> > > 1 files changed, 3 insertions(+), 3 deletions(-)
> > >
> > >diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c
> > >index ef9c34a..473c72b 100644
> > >--- a/arch/mips/cavium-octeon/smp.c
> > >+++ b/arch/mips/cavium-octeon/smp.c
> > >@@ -257,7 +257,7 @@ DEFINE_PER_CPU(int, cpu_state);
> > >
> > > extern void fixup_irqs(void);
> > >
> > >-static DEFINE_SPINLOCK(smp_reserve_lock);
> > >+static DEFINE_RAW_SPINLOCK(smp_reserve_lock);
> > >
> >
> > Ralf added this in 773cb77d (MIPS: Cavium: Add CPU hotplugging code.)
> >
> > I'm not even sure what this lock is supposed to be protecting, so I
> > would like Ralf to take a look.
> >
> > You can add an Acked-by: from me for either this patch as is, or if
> > Ralf thinks it is OK, removing the lock entirely.
> >
> > In any event we can merge this via Ralf's tree.
>
> The 773cb77d patch has a long history but I think I first worked on it for
> Wind River Linux 2.0 which was 2.6.21-based, then broke it out and pushed
> it upstream. In 2.6.21 it was probably infected by the the smp_reserve_lock
> virus in the s390 code for no good reason. So I agree, the lock can
> be dropped and I'm queueing a patch to do so for 3.5.
I'm OK with dropping it ;-)
Thanks,
Yong
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-05-17 10:15 [PATCH -rt] MIPS: Octeon: convert smp_reserve_lock to raw spinlock Yong Zhang
2012-05-17 16:30 ` David Daney
2012-05-17 20:50 ` Ralf Baechle
2012-05-18 2:29 ` Yong Zhang
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