linux-kernel - [PATCH 4.4 180/183] bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap

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Date:   Tue, 28 Jan 2020 15:06:39 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>
Subject: [PATCH 4.4 180/183] bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free()

From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

commit c42b65e363ce97a828f81b59033c3558f8fa7f70 upstream.

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@...ux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 include/linux/bitmap.h |    8 ++++++++
 lib/bitmap.c           |   20 ++++++++++++++++++++
 2 files changed, 28 insertions(+)

--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -84,6 +84,14 @@
  */
 
 /*
+ * 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:
  */
 
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -12,6 +12,7 @@
 #include <linux/bitmap.h>
 #include <linux/bitops.h>
 #include <linux/bug.h>
+#include <linux/slab.h>
 
 #include <asm/page.h>
 #include <asm/uaccess.h>
@@ -1081,3 +1082,22 @@ void bitmap_copy_le(unsigned long *dst,
 }
 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);