Staging: meilhaus: convert nested spin_lock_irqsave to spin_lock

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>

diff --git a/drivers/staging/meilhaus/me4600_ai.c b/drivers/staging/meilhaus/me4600_ai.c
index e496d0c8d484dcb3d6e3d544de72083d9319f418..fd9daa942fb30ad25da81a7a18ec5889c518dae8 100644 (file)
--- a/drivers/staging/meilhaus/me4600_ai.c
+++ b/drivers/staging/meilhaus/me4600_ai.c
@@ -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;