[PATCH v2 3/5] bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free()

From: Andy Shevchenko
Date: Fri Jun 15 2018 - 09:20:37 EST


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.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
include/linux/bitmap.h | 8 ++++++++
lib/bitmap.c | 19 +++++++++++++++++++
2 files changed, 27 insertions(+)

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
@@ -104,6 +104,14 @@
* contain all bit positions from 0 to 'bits' - 1.
*/

+/*
+ * 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 33e95cd359a2..09acf2fd6a35 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>

@@ -1125,6 +1126,24 @@ 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
--
2.17.1