bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free()

A lot of code become ugly because of open coding allocations for bitmaps.

Introduce three helpers to allow users be more clear of intention
and keep their code neat.

Note, due to multiple circular dependencies we may not provide
the helpers as inliners. For now we keep them exported and, perhaps,
at some point in the future we will sort out header inclusion and
inheritance.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

2 files changed, 28 insertions, 0 deletions

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 1ee46f492267..acf5e8df3504 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -105,6 +105,14 @@
  */
 
 /*
+ * Allocation and deallocation of bitmap.
+ * Provided in lib/bitmap.c to avoid circular dependency.
+ */
+extern unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
+extern unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
+extern void bitmap_free(const unsigned long *bitmap);
+
+/*
  * lib/bitmap.c provides these functions:
  */
 
diff --git a/lib/bitmap.c b/lib/bitmap.c
index a42eff7e8c48..5b476d8414be 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -13,6 +13,7 @@
 #include <linux/bitops.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
+#include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
 
@@ -1128,6 +1129,25 @@ void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int n
 EXPORT_SYMBOL(bitmap_copy_le);
 #endif
 
+unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
+{
+	return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
+			     flags);
+}
+EXPORT_SYMBOL(bitmap_alloc);
+
+unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
+{
+	return bitmap_alloc(nbits, flags | __GFP_ZERO);
+}
+EXPORT_SYMBOL(bitmap_zalloc);
+
+void bitmap_free(const unsigned long *bitmap)
+{
+	kfree(bitmap);
+}
+EXPORT_SYMBOL(bitmap_free);
+
 #if BITS_PER_LONG == 64
 /**
  * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap