[patch 69/86] lib/bitmap: introduce bitmap_replace() helper

Andrew Morton
2019-12-05T00:53:29Z

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: lib/bitmap: introduce bitmap_replace() helper

In some drivers we want to have a single operation over bitmap which is an
equivalent to:

*dst = (*old & ~(*mask)) | (*new & *mask)

Introduce bitmap_replace() helper for this.

Link: http://lkml.kernel.org/r/20191022172922.61232-8-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/bitmap.h | 16 ++++++++++++++++
lib/bitmap.c | 12 ++++++++++++
lib/test_bitmap.c | 38 ++++++++++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+)

--- a/include/linux/bitmap.h~bitmap-introduce-bitmap_replace-helper
+++ a/include/linux/bitmap.h
@@ -53,6 +53,7 @@
* bitmap_find_next_zero_area_off(buf, len, pos, n, mask) as above
* bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n
* bitmap_shift_left(dst, src, n, nbits) *dst = *src << n
+ * bitmap_replace(dst, old, new, mask, nbits) *dst = (*old & ~(*mask)) | (*new & *mask)
* bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src)
* bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit)
* bitmap_onto(dst, orig, relmap, nbits) *dst = orig relative to relmap
@@ -140,6 +141,9 @@ extern void __bitmap_xor(unsigned long *
const unsigned long *bitmap2, unsigned int nbits);
extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, unsigned int nbits);
+extern void __bitmap_replace(unsigned long *dst,
+ const unsigned long *old, const unsigned long *new,
+ const unsigned long *mask, unsigned int nbits);
extern int __bitmap_intersects(const unsigned long *bitmap1,
const unsigned long *bitmap2, unsigned int nbits);
extern int __bitmap_subset(const unsigned long *bitmap1,
@@ -434,6 +438,18 @@ static inline void bitmap_shift_left(uns
__bitmap_shift_left(dst, src, shift, nbits);
}

+static inline void bitmap_replace(unsigned long *dst,
+ const unsigned long *old,
+ const unsigned long *new,
+ const unsigned long *mask,
+ unsigned int nbits)
+{
+ if (small_const_nbits(nbits))
+ *dst = (*old & ~(*mask)) | (*new & *mask);
+ else
+ __bitmap_replace(dst, old, new, mask, nbits);
+}
+
static inline int bitmap_parse(const char *buf, unsigned int buflen,
unsigned long *maskp, int nmaskbits)
{
--- a/lib/bitmap.c~bitmap-introduce-bitmap_replace-helper
+++ a/lib/bitmap.c
@@ -222,6 +222,18 @@ int __bitmap_andnot(unsigned long *dst,
}
EXPORT_SYMBOL(__bitmap_andnot);

+void __bitmap_replace(unsigned long *dst,
+ const unsigned long *old, const unsigned long *new,
+ const unsigned long *mask, unsigned int nbits)
+{
+ unsigned int k;
+ unsigned int nr = BITS_TO_LONGS(nbits);
+
+ for (k = 0; k < nr; k++)
+ dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]);
+}
+EXPORT_SYMBOL(__bitmap_replace);
+
int __bitmap_intersects(const unsigned long *bitmap1,
const unsigned long *bitmap2, unsigned int bits)
{
--- a/lib/test_bitmap.c~bitmap-introduce-bitmap_replace-helper
+++ a/lib/test_bitmap.c
@@ -42,6 +42,19 @@ static const unsigned long exp2[] __init
BITMAP_FROM_U64(0xffffffff77777777ULL),
};

+/* Fibonacci sequence */
+static const unsigned long exp2_to_exp3_mask[] __initconst = {
+ BITMAP_FROM_U64(0x008000020020212eULL),
+};
+/* exp3_0_1 = (exp2[0] & ~exp2_to_exp3_mask) | (exp2[1] & exp2_to_exp3_mask) */
+static const unsigned long exp3_0_1[] __initconst = {
+ BITMAP_FROM_U64(0x33b3333311313137ULL),
+};
+/* exp3_1_0 = (exp2[1] & ~exp2_to_exp3_mask) | (exp2[0] & exp2_to_exp3_mask) */
+static const unsigned long exp3_1_0[] __initconst = {
+ BITMAP_FROM_U64(0xff7fffff77575751ULL),
+};
+
static bool __init
__check_eq_uint(const char *srcfile, unsigned int line,
const unsigned int exp_uint, unsigned int x)
@@ -257,6 +270,30 @@ static void __init test_copy(void)
expect_eq_pbl("0-108,128-1023", bmap2, 1024);
}

+#define EXP2_IN_BITS (sizeof(exp2) * 8)
+
+static void __init test_replace(void)
+{
+ unsigned int nbits = 64;
+ DECLARE_BITMAP(bmap, 1024);
+
+ bitmap_zero(bmap, 1024);
+ bitmap_replace(bmap, &exp2[0], &exp2[1], exp2_to_exp3_mask, nbits);
+ expect_eq_bitmap(bmap, exp3_0_1, nbits);
+
+ bitmap_zero(bmap, 1024);
+ bitmap_replace(bmap, &exp2[1], &exp2[0], exp2_to_exp3_mask, nbits);
+ expect_eq_bitmap(bmap, exp3_1_0, nbits);
+
+ bitmap_fill(bmap, 1024);
+ bitmap_replace(bmap, &exp2[0], &exp2[1], exp2_to_exp3_mask, nbits);
+ expect_eq_bitmap(bmap, exp3_0_1, nbits);
+
+ bitmap_fill(bmap, 1024);
+ bitmap_replace(bmap, &exp2[1], &exp2[0], exp2_to_exp3_mask, nbits);
+ expect_eq_bitmap(bmap, exp3_1_0, nbits);
+}
+
#define PARSE_TIME 0x1

struct test_bitmap_parselist{
@@ -476,6 +513,7 @@ static void __init selftest(void)
test_zero_clear();
test_fill_set();
test_copy();
+ test_replace();
test_bitmap_arr32();
test_bitmap_parselist();
test_bitmap_parselist_user();
_