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

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Message-Id: <20180615132017.23889-4-andriy.shevchenko@linux.intel.com>
Date:   Fri, 15 Jun 2018 16:20:15 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>, dm-devel@...hat.com,
        Shaohua Li <shli@...nel.org>, linux-raid@...r.kernel.org,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        linux-input@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Yury Norov <ynorov@...iumnetworks.com>,
        linux-kernel@...r.kernel.org, mika.westerberg@...ux.intel.com
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v2 3/5] 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.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 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