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Date: Fri, 14 Aug 2020 23:19:03 -0400
From: "Joel Fernandes (Google)" <joel@...lfernandes.org>
To: linux-kernel@...r.kernel.org
Cc: Vineeth Pillai <viremana@...ux.microsoft.com>,
Joel Fernandes <joel@...lfernandes.org>,
Aaron Lu <aaron.lwe@...il.com>,
Aubrey Li <aubrey.li@...ux.intel.com>,
Julien Desfossez <jdesfossez@...italocean.com>,
Kees Cook <keescook@...omium.org>,
"Paul E. McKenney" <paulmck@...nel.org>,
Paul Turner <pjt@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
Steven Rostedt <rostedt@...dmis.org>,
Thomas Gleixner <tglx@...utronix.de>,
Tim Chen <tim.c.chen@...el.com>,
Tim Chen <tim.c.chen@...ux.intel.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
fweisbec@...il.com, kerrnel@...gle.com,
Phil Auld <pauld@...hat.com>,
Valentin Schneider <valentin.schneider@....com>,
Paolo Bonzini <pbonzini@...hat.com>,
Chen Yu <yu.c.chen@...el.com>,
Christian Brauner <christian.brauner@...ntu.com>
Subject: [PATCH RFC 07/12] bitops: Introduce find_next_or_bit
From: Vineeth Pillai <viremana@...ux.microsoft.com>
Hotplug fixes to core-scheduling require a new bitops API.
Introduce a new API find_next_or_bit() which returns the bit number of
the next set bit in OR-ed bit masks of the given bit masks.
Signed-off-by: Vineeth Pillai <viremana@...ux.microsoft.com>
Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
include/asm-generic/bitops/find.h | 16 +++++++++
lib/find_bit.c | 56 +++++++++++++++++++++++++------
2 files changed, 61 insertions(+), 11 deletions(-)
diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
index 9fdf21302fdf..0b476ca0d665 100644
--- a/include/asm-generic/bitops/find.h
+++ b/include/asm-generic/bitops/find.h
@@ -32,6 +32,22 @@ extern unsigned long find_next_and_bit(const unsigned long *addr1,
unsigned long offset);
#endif
+#ifndef find_next_or_bit
+/**
+ * find_next_or_bit - find the next set bit in any memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+extern unsigned long find_next_or_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long size,
+ unsigned long offset);
+#endif
+
#ifndef find_next_zero_bit
/**
* find_next_zero_bit - find the next cleared bit in a memory region
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 49f875f1baf7..2eca8e2b16b1 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -19,7 +19,14 @@
#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_or_bit)
+
+typedef enum {
+ FNB_AND = 0,
+ FNB_OR = 1,
+ FNB_MAX = 2
+} fnb_bwops_t;
+
/*
* This is a common helper function for find_next_bit, find_next_zero_bit, and
* find_next_and_bit. The differences are:
@@ -29,7 +36,8 @@
*/
static 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 invert,
+ fnb_bwops_t type, unsigned long le)
{
unsigned long tmp, mask;
@@ -37,8 +45,16 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
return nbits;
tmp = addr1[start / BITS_PER_LONG];
- if (addr2)
- tmp &= addr2[start / BITS_PER_LONG];
+ if (addr2) {
+ switch (type) {
+ case FNB_AND:
+ tmp &= addr2[start / BITS_PER_LONG];
+ break;
+ case FNB_OR:
+ tmp |= addr2[start / BITS_PER_LONG];
+ break;
+ }
+ }
tmp ^= invert;
/* Handle 1st word. */
@@ -56,8 +72,16 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
return nbits;
tmp = addr1[start / BITS_PER_LONG];
- if (addr2)
- tmp &= addr2[start / BITS_PER_LONG];
+ if (addr2) {
+ switch (type) {
+ case FNB_AND:
+ tmp &= addr2[start / BITS_PER_LONG];
+ break;
+ case FNB_OR:
+ tmp |= addr2[start / BITS_PER_LONG];
+ break;
+ }
+ }
tmp ^= invert;
}
@@ -75,7 +99,7 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
{
- return _find_next_bit(addr, NULL, size, offset, 0UL, 0);
+ return _find_next_bit(addr, NULL, size, offset, 0UL, FNB_AND, 0);
}
EXPORT_SYMBOL(find_next_bit);
#endif
@@ -84,7 +108,7 @@ EXPORT_SYMBOL(find_next_bit);
unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
{
- return _find_next_bit(addr, NULL, size, offset, ~0UL, 0);
+ return _find_next_bit(addr, NULL, size, offset, ~0UL, FNB_AND, 0);
}
EXPORT_SYMBOL(find_next_zero_bit);
#endif
@@ -94,11 +118,21 @@ unsigned long find_next_and_bit(const unsigned long *addr1,
const unsigned long *addr2, unsigned long size,
unsigned long offset)
{
- return _find_next_bit(addr1, addr2, size, offset, 0UL, 0);
+ return _find_next_bit(addr1, addr2, size, offset, 0UL, FNB_AND, 0);
}
EXPORT_SYMBOL(find_next_and_bit);
#endif
+#if !defined(find_next_or_bit)
+unsigned long find_next_or_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long size,
+ unsigned long offset)
+{
+ return _find_next_bit(addr1, addr2, size, offset, 0UL, FNB_OR, 0);
+}
+EXPORT_SYMBOL(find_next_or_bit);
+#endif
+
#ifndef find_first_bit
/*
* Find the first set bit in a memory region.
@@ -161,7 +195,7 @@ EXPORT_SYMBOL(find_last_bit);
unsigned long find_next_zero_bit_le(const void *addr, unsigned
long size, unsigned long offset)
{
- return _find_next_bit(addr, NULL, size, offset, ~0UL, 1);
+ return _find_next_bit(addr, NULL, size, offset, ~0UL, FNB_AND, 1);
}
EXPORT_SYMBOL(find_next_zero_bit_le);
#endif
@@ -170,7 +204,7 @@ EXPORT_SYMBOL(find_next_zero_bit_le);
unsigned long find_next_bit_le(const void *addr, unsigned
long size, unsigned long offset)
{
- return _find_next_bit(addr, NULL, size, offset, 0UL, 1);
+ return _find_next_bit(addr, NULL, size, offset, 0UL, FNB_AND, 1);
}
EXPORT_SYMBOL(find_next_bit_le);
#endif
--
2.28.0.220.ged08abb693-goog
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