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Date: Wed, 17 Aug 2022 18:58:08 +0100
From: Valentin Schneider <vschneid@...hat.com>
To: netdev@...r.kernel.org, linux-rdma@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Saeed Mahameed <saeedm@...dia.com>,
Leon Romanovsky <leon@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Yury Norov <yury.norov@...il.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Mel Gorman <mgorman@...e.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Barry Song <song.bao.hua@...ilicon.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Tony Luck <tony.luck@...el.com>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
Gal Pressman <gal@...dia.com>, Tariq Toukan <tariqt@...dia.com>
Subject: [PATCH v2 1/5] bitops: Introduce find_next_andnot_bit()
In preparation of introducing for_each_cpu_andnot(), add a variant of
find_next_bit() that negate the bits in @addr2 when ANDing them with the
bits in @addr1.
Note that the _find_next_bit() @invert argument now gets split into two:
@invert1 for words in @addr1, @invert2 for words in @addr2. The only
current users of _find_next_bit() with @invert set are:
o find_next_zero_bit()
o find_next_zero_bit_le()
and neither of these pass an @addr2, so the conversion is straightforward.
Signed-off-by: Valentin Schneider <vschneid@...hat.com>
---
include/linux/find.h | 44 ++++++++++++++++++++++++++++++++++++++------
lib/find_bit.c | 23 ++++++++++++-----------
2 files changed, 50 insertions(+), 17 deletions(-)
diff --git a/include/linux/find.h b/include/linux/find.h
index 424ef67d4a42..920597de4e62 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -10,7 +10,8 @@
extern unsigned long _find_next_bit(const unsigned long *addr1,
const unsigned long *addr2, unsigned long nbits,
- unsigned long start, unsigned long invert, unsigned long le);
+ unsigned long start, unsigned long invert1, unsigned long invert2,
+ unsigned long le);
extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size);
extern unsigned long _find_first_and_bit(const unsigned long *addr1,
const unsigned long *addr2, unsigned long size);
@@ -41,7 +42,7 @@ unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
return val ? __ffs(val) : size;
}
- return _find_next_bit(addr, NULL, size, offset, 0UL, 0);
+ return _find_next_bit(addr, NULL, size, offset, 0UL, 0UL, 0);
}
#endif
@@ -71,7 +72,38 @@ unsigned long find_next_and_bit(const unsigned long *addr1,
return val ? __ffs(val) : size;
}
- return _find_next_bit(addr1, addr2, size, offset, 0UL, 0);
+ return _find_next_bit(addr1, addr2, size, offset, 0UL, 0UL, 0);
+}
+#endif
+
+#ifndef find_next_andnot_bit
+/**
+ * find_next_andnot_bit - find the next set bit in one memory region
+ * but not in the other
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @size: The bitmap size in bits
+ * @offset: The bitnumber to start searching at
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+static inline
+unsigned long find_next_andnot_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long size,
+ unsigned long offset)
+{
+ if (small_const_nbits(size)) {
+ unsigned long val;
+
+ if (unlikely(offset >= size))
+ return size;
+
+ val = *addr1 & ~*addr2 & GENMASK(size - 1, offset);
+ return val ? __ffs(val) : size;
+ }
+
+ return _find_next_bit(addr1, addr2, size, offset, 0UL, ~0UL, 0);
}
#endif
@@ -99,7 +131,7 @@ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
return val == ~0UL ? size : ffz(val);
}
- return _find_next_bit(addr, NULL, size, offset, ~0UL, 0);
+ return _find_next_bit(addr, NULL, size, offset, ~0UL, 0UL, 0);
}
#endif
@@ -247,7 +279,7 @@ unsigned long find_next_zero_bit_le(const void *addr, unsigned
return val == ~0UL ? size : ffz(val);
}
- return _find_next_bit(addr, NULL, size, offset, ~0UL, 1);
+ return _find_next_bit(addr, NULL, size, offset, ~0UL, 0UL, 1);
}
#endif
@@ -266,7 +298,7 @@ unsigned long find_next_bit_le(const void *addr, unsigned
return val ? __ffs(val) : size;
}
- return _find_next_bit(addr, NULL, size, offset, 0UL, 1);
+ return _find_next_bit(addr, NULL, size, offset, 0UL, 0UL, 1);
}
#endif
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 1b8e4b2a9cba..c46b66d7d2b4 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -21,27 +21,29 @@
#if !defined(find_next_bit) || !defined(find_next_zero_bit) || \
!defined(find_next_bit_le) || !defined(find_next_zero_bit_le) || \
- !defined(find_next_and_bit)
+ !defined(find_next_and_bit) || !defined(find_next_andnot_bit)
/*
* This is a common helper function for find_next_bit, find_next_zero_bit, and
* find_next_and_bit. The differences are:
- * - The "invert" argument, which is XORed with each fetched word before
- * searching it for one bits.
* - The optional "addr2", which is anded with "addr1" if present.
+ * - The "invert" arguments, which are XORed with each fetched word (invert1
+ * for words in addr1, invert2 for those in addr2) before searching it for
+ * one bits.
*/
unsigned long _find_next_bit(const unsigned long *addr1,
- const unsigned long *addr2, unsigned long nbits,
- unsigned long start, unsigned long invert, unsigned long le)
+ const unsigned long *addr2,
+ unsigned long nbits, unsigned long start,
+ unsigned long invert1, unsigned long invert2,
+ unsigned long le)
{
unsigned long tmp, mask;
if (unlikely(start >= nbits))
return nbits;
- tmp = addr1[start / BITS_PER_LONG];
+ tmp = addr1[start / BITS_PER_LONG] ^ invert1;
if (addr2)
- tmp &= addr2[start / BITS_PER_LONG];
- tmp ^= invert;
+ tmp &= addr2[start / BITS_PER_LONG] ^ invert2;
/* Handle 1st word. */
mask = BITMAP_FIRST_WORD_MASK(start);
@@ -57,10 +59,9 @@ unsigned long _find_next_bit(const unsigned long *addr1,
if (start >= nbits)
return nbits;
- tmp = addr1[start / BITS_PER_LONG];
+ tmp = addr1[start / BITS_PER_LONG] ^ invert1;
if (addr2)
- tmp &= addr2[start / BITS_PER_LONG];
- tmp ^= invert;
+ tmp &= addr2[start / BITS_PER_LONG] ^ invert2;
}
if (le)
--
2.31.1
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