dmapool: don't memset on free twice

If debug is enabled, dmapool will poison the range, so no need to clear it
to 0 immediately before writing over it.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 2d55c16 ("dmapool: create/destroy cleanup")
Signed-off-by: Keith Busch <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Tony Battersby <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: keithbusch

mm/dmapool.c

@@ -160,6 +160,8 @@ static void pool_check_block(struct dma_pool *pool, void *retval,
 static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
 			  void *vaddr, dma_addr_t dma)
 {
+	if (want_init_on_free())
+		memset(vaddr, 0, pool->size);
 	return false;
 }
 
@@ -441,8 +443,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
 		return;
 	}
 
-	if (want_init_on_free())
-		memset(vaddr, 0, pool->size);
 	if (pool_page_err(pool, page, vaddr, dma)) {
 		spin_unlock_irqrestore(&pool->lock, flags);
 		return;