2 files changed, 26 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 95de3102bc87..623ef24c2381 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -427,6 +427,16 @@ config DEBUG_VM
 
           If unsure, say N.
 
+config DEBUG_WRITECOUNT
+        bool "Debug filesystem writers count"
+        depends on DEBUG_KERNEL
+        help
+          Enable this to catch wrong use of the writers count in struct
+          vfsmount.  This will increase the size of each file struct by
+          32 bits.
+
+          If unsure, say N.
+
 config DEBUG_LIST
         bool "Debug linked list manipulation"
         depends on DEBUG_KERNEL
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 2c9242e3fed0..a6939e18d7bb 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -316,6 +316,22 @@ int bitmap_scnprintf(char *buf, unsigned int buflen,
 EXPORT_SYMBOL(bitmap_scnprintf);
 
 /**
+ * bitmap_scnprintf_len - return buffer length needed to convert
+ * bitmap to an ASCII hex string.
+ * @len: number of bits to be converted
+ */
+int bitmap_scnprintf_len(unsigned int len)
+{
+        /* we need 9 chars per word for 32 bit words (8 hexdigits + sep/null) */
+        int bitslen = ALIGN(len, CHUNKSZ);
+        int wordlen = CHUNKSZ / 4;
+        int buflen = (bitslen / wordlen) * (wordlen + 1) * sizeof(char);
+
+        return buflen;
+}
+EXPORT_SYMBOL(bitmap_scnprintf_len);
+
+/**
  * __bitmap_parse - convert an ASCII hex string into a bitmap.
  * @buf: pointer to buffer containing string.
  * @buflen: buffer size in bytes.  If string is smaller than this