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Date: Sun, 6 Dec 2020 15:46:24 +0900
From: Levi Yun <ppbuk5246@...il.com>
To: akpm@...ux-foundation.org, yury.norov@...il.com,
andriy.shevchenko@...ux.intel.com,
richard.weiyang@...ux.alibaba.com, christian.brauner@...ntu.com,
arnd@...db.de, jpoimboe@...hat.com, changbin.du@...el.com,
rdunlap@...radead.org, masahiroy@...nel.org,
gregkh@...uxfoundation.org, peterz@...radead.org,
peter.enderborg@...y.com, krzk@...nel.org,
brendanhiggins@...gle.com, keescook@...omium.org,
broonie@...nel.org, matti.vaittinen@...rohmeurope.com,
mhiramat@...nel.org, jpa@....mail.kapsi.fi, nivedita@...m.mit.edu,
glider@...gle.com, orson.zhai@...soc.com,
takahiro.akashi@...aro.org, clm@...com, josef@...icpanda.com,
dsterba@...e.com, dushistov@...l.ru
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
linux-btrfs@...r.kernel.org
Subject: [PATCH v2 1/8] lib/find_bit.c: Add find_last_zero_bit
Inspired find_next_*_bit and find_last_bit, add find_last_zero_bit
And add le support about find_last_bit and find_last_zero_bit.
Signed-off-by: Levi Yun <ppbuk5246@...il.com>
---
lib/find_bit.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 62 insertions(+), 2 deletions(-)
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 4a8751010d59..f9dda2bf7fa9 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -90,7 +90,7 @@ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
EXPORT_SYMBOL(find_next_zero_bit);
#endif
-#if !defined(find_next_and_bit)
+#ifndef find_next_and_bit
unsigned long find_next_and_bit(const unsigned long *addr1,
const unsigned long *addr2, unsigned long size,
unsigned long offset)
@@ -141,7 +141,7 @@ unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
{
if (size) {
unsigned long val = BITMAP_LAST_WORD_MASK(size);
- unsigned long idx = (size-1) / BITS_PER_LONG;
+ unsigned long idx = (size - 1) / BITS_PER_LONG;
do {
val &= addr[idx];
@@ -156,6 +156,27 @@ unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
EXPORT_SYMBOL(find_last_bit);
#endif
+#ifndef find_last_zero_bit
+unsigned long find_last_zero_bit(const unsigned long *addr, unsigned long size)
+{
+ if (size) {
+ unsigned long val = BITMAP_LAST_WORD_MASK(size);
+ unsigned long idx = (size - 1) / BITS_PER_LONG;
+
+ do {
+ val &= ~addr[idx];
+ if (val)
+ return idx * BITS_PER_LONG + __fls(val);
+
+ val = ~0ul;
+ } while (idx--);
+ }
+
+ return size;
+}
+EXPORT_SYMBOL(find_last_zero_bit);
+#endif
+
#ifdef __BIG_ENDIAN
#ifndef find_next_zero_bit_le
@@ -176,6 +197,45 @@ unsigned long find_next_bit_le(const void *addr, unsigned
EXPORT_SYMBOL(find_next_bit_le);
#endif
+static unsigned long _find_last_bit_le(const unsigned long *addr,
+ unsigned long size, unsigned long invert)
+{
+ if (size) {
+ unsigned long val = BITMAP_LAST_WORD_MASK(size);
+ unsigned long tmp;
+ unsigned long idx = (size - 1) / BITS_PER_LONG;
+
+ val = swab(val);
+
+ do {
+ tmp = swab(addr[idx]);
+ tmp ^= invert;
+ val &= tmp;
+ if (val)
+ return idx * BITS_PER_LONG + __fls(val);
+
+ val = ~0ul;
+ } while (idx--);
+ }
+ return size;
+}
+
+#ifndef find_last_zero_bit_le
+unsigned long find_last_zero_bit_le(const unsigned void *addr, unsigned long size)
+{
+ return _find_last_bit_le(addr, size, ~0UL);
+}
+EXPORT_SYMBOL(find_last_zero_bit_le);
+#endif
+
+#ifdef find_last_bit_le
+unsigned long find_last_bit_le(const unsigned void *addr, unsigned long size)
+{
+ return _find_last_bit_le(addr, size, 0UL);
+}
+EXPORT_SYMBOL(find_last_bit_le);
+#endif
+
#endif /* __BIG_ENDIAN */
unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,
--
2.27.0
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