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-rw-r--r--arch/m68k/atari/stdma.c61
1 files changed, 40 insertions, 21 deletions
diff --git a/arch/m68k/atari/stdma.c b/arch/m68k/atari/stdma.c
index ddbf43ca8858..e5a66596b116 100644
--- a/arch/m68k/atari/stdma.c
+++ b/arch/m68k/atari/stdma.c
@@ -59,6 +59,31 @@ static irqreturn_t stdma_int (int irq, void *dummy);
/************************* End of Prototypes **************************/
+/**
+ * stdma_try_lock - attempt to acquire ST DMA interrupt "lock"
+ * @handler: interrupt handler to use after acquisition
+ *
+ * Returns !0 if lock was acquired; otherwise 0.
+ */
+
+int stdma_try_lock(irq_handler_t handler, void *data)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ if (stdma_locked) {
+ local_irq_restore(flags);
+ return 0;
+ }
+
+ stdma_locked = 1;
+ stdma_isr = handler;
+ stdma_isr_data = data;
+ local_irq_restore(flags);
+ return 1;
+}
+EXPORT_SYMBOL(stdma_try_lock);
+
/*
* Function: void stdma_lock( isrfunc isr, void *data )
@@ -78,19 +103,10 @@ static irqreturn_t stdma_int (int irq, void *dummy);
void stdma_lock(irq_handler_t handler, void *data)
{
- unsigned long flags;
-
- local_irq_save(flags); /* protect lock */
-
/* Since the DMA is used for file system purposes, we
have to sleep uninterruptible (there may be locked
buffers) */
- wait_event(stdma_wait, !stdma_locked);
-
- stdma_locked = 1;
- stdma_isr = handler;
- stdma_isr_data = data;
- local_irq_restore(flags);
+ wait_event(stdma_wait, stdma_try_lock(handler, data));
}
EXPORT_SYMBOL(stdma_lock);
@@ -122,22 +138,25 @@ void stdma_release(void)
EXPORT_SYMBOL(stdma_release);
-/*
- * Function: int stdma_others_waiting( void )
- *
- * Purpose: Check if someone waits for the ST-DMA lock.
- *
- * Inputs: none
- *
- * Returns: 0 if no one is waiting, != 0 otherwise
+/**
+ * stdma_is_locked_by - allow lock holder to check whether it needs to release.
+ * @handler: interrupt handler previously used to acquire lock.
*
+ * Returns !0 if locked for the given handler; 0 otherwise.
*/
-int stdma_others_waiting(void)
+int stdma_is_locked_by(irq_handler_t handler)
{
- return waitqueue_active(&stdma_wait);
+ unsigned long flags;
+ int result;
+
+ local_irq_save(flags);
+ result = stdma_locked && (stdma_isr == handler);
+ local_irq_restore(flags);
+
+ return result;
}
-EXPORT_SYMBOL(stdma_others_waiting);
+EXPORT_SYMBOL(stdma_is_locked_by);
/*