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/1492065666-3816-1-git-send-email-pagupta@redhat.com
Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ville Syrjl <ville.syrjala@linux.intel.com>
Cc: Miles Chen <miles.chen@mediatek.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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;
 }