dmapool: use sysfs_emit() instead of scnprintf()

Use sysfs_emit instead of scnprintf, snprintf or sprintf.

Link: https://lkml.kernel.org/r/20230126215125.4069751-4-kbusch@meta.com
Fixes: 2d55c16c0c ("dmapool: create/destroy cleanup")
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/dmapool.c

@@ -64,18 +64,11 @@ static DEFINE_MUTEX(pools_reg_lock);
 
 static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	unsigned temp;
+	int size;
-	unsigned size;
-	char *next;
 	struct dma_page *page;
 	struct dma_pool *pool;
 
-	next = buf;
+	size = sysfs_emit(buf, "poolinfo - 0.1\n");
-	size = PAGE_SIZE;
-
-	temp = scnprintf(next, size, "poolinfo - 0.1\n");
-	size -= temp;
-	next += temp;
 
 	mutex_lock(&pools_lock);
 	list_for_each_entry(pool, &dev->dma_pools, pools) {
@@ -90,16 +83,14 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha
 		spin_unlock_irq(&pool->lock);
 
 		/* per-pool info, no real statistics yet */
-		temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n",
+		size += sysfs_emit_at(buf, size, "%-16s %4u %4zu %4zu %2u\n",
-				 pool->name, blocks,
+				      pool->name, blocks,
-				 pages * (pool->allocation / pool->size),
+				      pages * (pool->allocation / pool->size),
-				 pool->size, pages);
+				      pool->size, pages);
-		size -= temp;
-		next += temp;
 	}
 	mutex_unlock(&pools_lock);
 
-	return PAGE_SIZE - size;
+	return size;
 }
 
 static DEVICE_ATTR_RO(pools);