[PATCH v8 02/15] swiotlb: Refactor swiotlb_create_debugfs

[Claire Chang <tientzu@xxxxxxxxxxxx>]

Split the debugfs creation to make the code reusable for supporting
different bounce buffer pools, e.g. restricted DMA pool.

Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
---
 kernel/dma/swiotlb.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index d3232fc19385..b849b01a446f 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -64,6 +64,7 @@
 enum swiotlb_force swiotlb_force;
 
 struct io_tlb_mem *io_tlb_default_mem;
+static struct dentry *debugfs_dir;
 
 /*
  * Max segment that we can provide which (if pages are contingous) will
@@ -662,18 +663,30 @@ EXPORT_SYMBOL_GPL(is_swiotlb_active);
 
 #ifdef CONFIG_DEBUG_FS
 
-static int __init swiotlb_create_debugfs(void)
+static void swiotlb_create_debugfs(struct io_tlb_mem *mem, const char *name)
 {
-	struct io_tlb_mem *mem = io_tlb_default_mem;
-
 	if (!mem)
-		return 0;
-	mem->debugfs = debugfs_create_dir("swiotlb", NULL);
+		return;
+
+	mem->debugfs = debugfs_create_dir(name, debugfs_dir);
 	debugfs_create_ulong("io_tlb_nslabs", 0400, mem->debugfs, &mem->nslabs);
 	debugfs_create_ulong("io_tlb_used", 0400, mem->debugfs, &mem->used);
+}
+
+static int __init swiotlb_create_default_debugfs(void)
+{
+	struct io_tlb_mem *mem = io_tlb_default_mem;
+
+	if (mem) {
+		swiotlb_create_debugfs(mem, "swiotlb");
+		debugfs_dir = mem->debugfs;
+	} else {
+		debugfs_dir = debugfs_create_dir("swiotlb", NULL);
+	}
+
 	return 0;
 }
 
-late_initcall(swiotlb_create_debugfs);
+late_initcall(swiotlb_create_default_debugfs);
 
 #endif
-- 
2.31.1.818.g46aad6cb9e-goog