Re: [PATCHv6 01/11] ARM: OMAP: clockdomain: Fix locking on _clkdm_clk_hwmod_enable / disable

2012-10-16 Thread Paul Walmsley 
On Tue, 25 Sep 2012, Tero Kristo wrote:

 Previously the code only acquired spinlock after increasing / decreasing
 the usecount value, which is wrong. This leaves a small window where
 a task switch may occur between the check of the usecount and the actual
 wakeup / sleep of the domain. Fixed by moving the spinlock locking before
 the usecount access. Left the usecount as atomic_t if someone wants an
 easy access to the parameter through atomic_read.
 
 Signed-off-by: Tero Kristo t-kri...@ti.com

Acked-by: Paul Walmsley p...@pwsan.com

- Paul
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Re: [PATCHv6 01/11] ARM: OMAP: clockdomain: Fix locking on _clkdm_clk_hwmod_enable / disable

2012-10-16 Thread Tony Lindgren 
* Paul Walmsley p...@pwsan.com [121016 19:26]:
 On Tue, 25 Sep 2012, Tero Kristo wrote:
 
  Previously the code only acquired spinlock after increasing / decreasing
  the usecount value, which is wrong. This leaves a small window where
  a task switch may occur between the check of the usecount and the actual
  wakeup / sleep of the domain. Fixed by moving the spinlock locking before
  the usecount access. Left the usecount as atomic_t if someone wants an
  easy access to the parameter through atomic_read.
  
  Signed-off-by: Tero Kristo t-kri...@ti.com
 
 Acked-by: Paul Walmsley p...@pwsan.com

OK I'll apply this into omap-for-v3.7-rc1/fixes-take4.

Regards,

Tony
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Re: [PATCHv6 01/11] ARM: OMAP: clockdomain: Fix locking on _clkdm_clk_hwmod_enable / disable

2012-10-15 Thread Paul Walmsley 
On Tue, 25 Sep 2012, Tero Kristo wrote:

 Previously the code only acquired spinlock after increasing / decreasing
 the usecount value, which is wrong. This leaves a small window where
 a task switch may occur between the check of the usecount and the actual
 wakeup / sleep of the domain. Fixed by moving the spinlock locking before
 the usecount access. Left the usecount as atomic_t if someone wants an
 easy access to the parameter through atomic_read.
 
 Signed-off-by: Tero Kristo t-kri...@ti.com

Thanks, queued for 3.7-rc fixes.


- Paul
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[PATCHv6 01/11] ARM: OMAP: clockdomain: Fix locking on _clkdm_clk_hwmod_enable / disable

2012-09-25 Thread Tero Kristo 
Previously the code only acquired spinlock after increasing / decreasing
the usecount value, which is wrong. This leaves a small window where
a task switch may occur between the check of the usecount and the actual
wakeup / sleep of the domain. Fixed by moving the spinlock locking before
the usecount access. Left the usecount as atomic_t if someone wants an
easy access to the parameter through atomic_read.

Signed-off-by: Tero Kristo t-kri...@ti.com
---
 arch/arm/mach-omap2/clockdomain.c |   15 +++
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-omap2/clockdomain.c 
b/arch/arm/mach-omap2/clockdomain.c
index 8664f5a..173905d 100644
--- a/arch/arm/mach-omap2/clockdomain.c
+++ b/arch/arm/mach-omap2/clockdomain.c
@@ -914,15 +914,18 @@ static int _clkdm_clk_hwmod_enable(struct clockdomain 
*clkdm)
if (!clkdm || !arch_clkdm || !arch_clkdm-clkdm_clk_enable)
return -EINVAL;
 
+   spin_lock_irqsave(clkdm-lock, flags);
+
/*
 * For arch's with no autodeps, clkcm_clk_enable
 * should be called for every clock instance or hwmod that is
 * enabled, so the clkdm can be force woken up.
 */
-   if ((atomic_inc_return(clkdm-usecount)  1)  autodeps)
+   if ((atomic_inc_return(clkdm-usecount)  1)  autodeps) {
+   spin_unlock_irqrestore(clkdm-lock, flags);
return 0;
+   }
 
-   spin_lock_irqsave(clkdm-lock, flags);
arch_clkdm-clkdm_clk_enable(clkdm);
pwrdm_state_switch(clkdm-pwrdm.ptr);
spin_unlock_irqrestore(clkdm-lock, flags);
@@ -939,15 +942,19 @@ static int _clkdm_clk_hwmod_disable(struct clockdomain 
*clkdm)
if (!clkdm || !arch_clkdm || !arch_clkdm-clkdm_clk_disable)
return -EINVAL;
 
+   spin_lock_irqsave(clkdm-lock, flags);
+
if (atomic_read(clkdm-usecount) == 0) {
+   spin_unlock_irqrestore(clkdm-lock, flags);
WARN_ON(1); /* underflow */
return -ERANGE;
}
 
-   if (atomic_dec_return(clkdm-usecount)  0)
+   if (atomic_dec_return(clkdm-usecount)  0) {
+   spin_unlock_irqrestore(clkdm-lock, flags);
return 0;
+   }
 
-   spin_lock_irqsave(clkdm-lock, flags);
arch_clkdm-clkdm_clk_disable(clkdm);
pwrdm_state_switch(clkdm-pwrdm.ptr);
spin_unlock_irqrestore(clkdm-lock, flags);
-- 
1.7.4.1

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