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Message-Id: <20230430171809.124686-3-yury.norov@gmail.com>
Date: Sun, 30 Apr 2023 10:18:03 -0700
From: Yury Norov <yury.norov@...il.com>
To: Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Yury Norov <yury.norov@...il.com>,
Saeed Mahameed <saeedm@...dia.com>,
Pawel Chmielewski <pawel.chmielewski@...el.com>,
Leon Romanovsky <leon@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Valentin Schneider <vschneid@...hat.com>,
Tariq Toukan <tariqt@...dia.com>,
Gal Pressman <gal@...dia.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Heiko Carstens <hca@...ux.ibm.com>,
Barry Song <baohua@...nel.org>
Subject: [PATCH v3 2/8] lib/find: add find_next_and_andnot_bit()
Similarly to find_nth_and_andnot_bit(), find_next_and_andnot_bit() is
a convenient helper that allows traversing bitmaps without storing
intermediate results in a temporary bitmap.
In the following patches the function is used to implement NUMA-aware
CPUs enumeration.
Signed-off-by: Yury Norov <yury.norov@...il.com>
---
include/linux/find.h | 43 +++++++++++++++++++++++++++++++++++++++++++
lib/find_bit.c | 12 ++++++++++++
2 files changed, 55 insertions(+)
diff --git a/include/linux/find.h b/include/linux/find.h
index 5e4f39ef2e72..90b68d76c073 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -16,6 +16,9 @@ unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned l
unsigned long nbits, unsigned long start);
unsigned long _find_next_or_bit(const unsigned long *addr1, const unsigned long *addr2,
unsigned long nbits, unsigned long start);
+unsigned long _find_next_and_andnot_bit(const unsigned long *addr1, const unsigned long *addr2,
+ const unsigned long *addr3, unsigned long nbits,
+ unsigned long start);
unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits,
unsigned long start);
extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size);
@@ -159,6 +162,40 @@ unsigned long find_next_or_bit(const unsigned long *addr1,
}
#endif
+#ifndef find_next_and_andnot_bit
+/**
+ * find_next_and_andnot_bit - find the next bit set in *addr1 and *addr2,
+ * excluding all the bits in *addr3
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @addr3: The third address to base the search on
+ * @size: The bitmap size in bits
+ * @offset: The bitnumber to start searching at
+ *
+ * Return: the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+static __always_inline
+unsigned long find_next_and_andnot_bit(const unsigned long *addr1,
+ const unsigned long *addr2,
+ const unsigned long *addr3,
+ unsigned long size,
+ unsigned long offset)
+{
+ if (small_const_nbits(size)) {
+ unsigned long val;
+
+ if (unlikely(offset >= size))
+ return size;
+
+ val = *addr1 & *addr2 & ~*addr3 & GENMASK(size - 1, offset);
+ return val ? __ffs(val) : size;
+ }
+
+ return _find_next_and_andnot_bit(addr1, addr2, addr3, size, offset);
+}
+#endif
+
#ifndef find_next_zero_bit
/**
* find_next_zero_bit - find the next cleared bit in a memory region
@@ -568,6 +605,12 @@ unsigned long find_next_bit_le(const void *addr, unsigned
(bit) = find_next_andnot_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
(bit)++)
+#define for_each_and_andnot_bit(bit, addr1, addr2, addr3, size) \
+ for ((bit) = 0; \
+ (bit) = find_next_and_andnot_bit((addr1), (addr2), (addr3), (size), (bit)),\
+ (bit) < (size); \
+ (bit)++)
+
#define for_each_or_bit(bit, addr1, addr2, size) \
for ((bit) = 0; \
(bit) = find_next_or_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 32f99e9a670e..4403e00890b1 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -182,6 +182,18 @@ unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned l
EXPORT_SYMBOL(_find_next_andnot_bit);
#endif
+#ifndef find_next_and_andnot_bit
+unsigned long _find_next_and_andnot_bit(const unsigned long *addr1,
+ const unsigned long *addr2,
+ const unsigned long *addr3,
+ unsigned long nbits,
+ unsigned long start)
+{
+ return FIND_NEXT_BIT(addr1[idx] & addr2[idx] & ~addr3[idx], /* nop */, nbits, start);
+}
+EXPORT_SYMBOL(_find_next_and_andnot_bit);
+#endif
+
#ifndef find_next_or_bit
unsigned long _find_next_or_bit(const unsigned long *addr1, const unsigned long *addr2,
unsigned long nbits, unsigned long start)
--
2.37.2
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