lib/dma-debug.c: make locking work for RT

Interrupt enable/disabled with spinlock is not a valid operation for RT
as it can make executing tasks sleep from a non-sleepable context.  So
convert it to spin_lock_irq[save, restore].

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Pankaj Gupta <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Niklas Söderlund <[email protected]>
Cc: Vinod Koul <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Ville Syrjl <[email protected]>
Cc: Miles Chen <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

lib/dma-debug.c

@@ -942,21 +942,17 @@ static int device_dma_allocations(struct device *dev, struct dma_debug_entry **o
 	unsigned long flags;
 	int count = 0, i;
 
-	local_irq_save(flags);
-
 	for (i = 0; i < HASH_SIZE; ++i) {
-		spin_lock(&dma_entry_hash[i].lock);
+		spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 		list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 			if (entry->dev == dev) {
 				count += 1;
 				*out_entry = entry;
 			}
 		}
-		spin_unlock(&dma_entry_hash[i].lock);
+		spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 	}
 
-	local_irq_restore(flags);
-
 	return count;
 }