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Staging: meilhaus: convert nested spin_lock_irqsave to spin_lock

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If spin_lock_irqsave is called twice in a row with the same second
argument, the interrupt state at the point of the second call overwrites
the value saved by the first call.  Indeed, the second call does not need
to save the interrupt state, so it is changed to a simple spin_lock.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression lock1,lock2;
expression flags;
@@

*spin_lock_irqsave(lock1,flags)
... when != flags
*spin_lock_irqsave(lock2,flags)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: David Kiliani <mail@davidkiliani.de>
Cc: Meilhaus Support <support@meilhaus.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Julia Lawall 2009-07-18 17:25:30 +02:00 committed by Greg Kroah-Hartman
parent c60adf37eb
commit 1dd7def0b5
1 changed files with 8 additions and 8 deletions
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16
drivers/staging/meilhaus/me4600_ai.c
View file

@ -760,7 +760,7 @@ static int me4600_ai_io_single_read(me_subdevice_t *subdevice,
// Mark that StreamConfig is removed.
instance->chan_list_len = 0;
spin_lock_irqsave(instance->ctrl_reg_lock, cpu_flags);
spin_lock(instance->ctrl_reg_lock);
/// @note Imprtant: Preserve EXT IRQ settings.
tmp = inl(instance->ctrl_reg);
// Clear FIFOs and dissable interrupts
@ -824,7 +824,7 @@ static int me4600_ai_io_single_read(me_subdevice_t *subdevice,
instance->ctrl_reg - instance->reg_base,
instance->single_config[channel].ctrl | tmp);
spin_unlock_irqrestore(instance->ctrl_reg_lock, cpu_flags);
spin_unlock(instance->ctrl_reg_lock);
if (!(instance->single_config[channel].ctrl & ME4600_AI_CTRL_BIT_EX_TRIG)) { // Software start
inl(instance->start_reg);
@ -877,7 +877,7 @@ static int me4600_ai_io_single_read(me_subdevice_t *subdevice,
}
// Restore settings.
spin_lock_irqsave(instance->ctrl_reg_lock, cpu_flags);
spin_lock(instance->ctrl_reg_lock);
tmp = inl(instance->ctrl_reg);
// Clear FIFOs and dissable interrupts.
tmp &=
@ -889,7 +889,7 @@ static int me4600_ai_io_single_read(me_subdevice_t *subdevice,
outl(tmp, instance->ctrl_reg);
PDEBUG_REG("ctrl_reg outl(0x%lX+0x%lX)=0x%x\n", instance->reg_base,
instance->ctrl_reg - instance->reg_base, tmp);
spin_unlock_irqrestore(instance->ctrl_reg_lock, cpu_flags);
spin_unlock(instance->ctrl_reg_lock);
spin_unlock_irqrestore(&instance->subdevice_lock, cpu_flags);
@ -1268,7 +1268,7 @@ static int me4600_ai_io_stream_config(me_subdevice_t *subdevice,
}
instance->status = ai_status_none;
spin_lock_irqsave(instance->ctrl_reg_lock, cpu_flags);
spin_lock(instance->ctrl_reg_lock);
// Stop all actions. Block all interrupts. Clear (disable) FIFOs.
ctrl =
ME4600_AI_CTRL_BIT_LE_IRQ_RESET | ME4600_AI_CTRL_BIT_HF_IRQ_RESET |
@ -1290,7 +1290,7 @@ static int me4600_ai_io_stream_config(me_subdevice_t *subdevice,
outl(tmp | ctrl, instance->ctrl_reg);
PDEBUG_REG("ctrl_reg outl(0x%lX+0x%lX)=0x%x\n", instance->reg_base,
instance->ctrl_reg - instance->reg_base, tmp | ctrl);
spin_unlock_irqrestore(instance->ctrl_reg_lock, cpu_flags);
spin_unlock(instance->ctrl_reg_lock);
// Write the channel list
for (i = 0; i < count; i++) {
@ -1529,7 +1529,7 @@ static int me4600_ai_io_stream_config(me_subdevice_t *subdevice,
ctrl |= (ME4600_AI_CTRL_BIT_HF_IRQ | ME4600_AI_CTRL_BIT_SC_IRQ | ME4600_AI_CTRL_BIT_LE_IRQ); //The last IRQ source (ME4600_AI_CTRL_BIT_LE_IRQ) is unused!
//Everything is good. Finalize
spin_lock_irqsave(instance->ctrl_reg_lock, cpu_flags);
spin_lock(instance->ctrl_reg_lock);
tmp = inl(instance->ctrl_reg);
//Preserve EXT IRQ and OFFSET settings. Clean other bits.
@ -1541,7 +1541,7 @@ static int me4600_ai_io_stream_config(me_subdevice_t *subdevice,
outl(ctrl | tmp, instance->ctrl_reg);
PDEBUG_REG("ctrl_reg outl(0x%lX+0x%lX)=0x%x\n", instance->reg_base,
instance->ctrl_reg - instance->reg_base, ctrl | tmp);
spin_unlock_irqrestore(instance->ctrl_reg_lock, cpu_flags);
spin_unlock(instance->ctrl_reg_lock);
//Set the global parameters end exit.
instance->chan_list_len = count;