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From:   Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        "H . Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
        linux-api@vger.kernel.org,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Florian Weimer <fw@deneb.enyo.de>, David.Laight@ACULAB.COM,
        carlos@redhat.com, Peter Oskolkov <posk@posk.io>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: [PATCH v3 08/23] cpumask: implement cpumask_{first,next}_{zero,one}_and_zero
Date:   Fri, 29 Jul 2022 15:02:10 -0400
Message-Id: <20220729190225.12726-9-mathieu.desnoyers@efficios.com>
In-Reply-To: <20220729190225.12726-1-mathieu.desnoyers@efficios.com>
References: <20220729190225.12726-1-mathieu.desnoyers@efficios.com>
Precedence: bulk

Allow finding the first or next bit within two input cpumasks which is
either:

- both zero and zero,
- respectively one and zero.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 include/linux/cpumask.h | 86 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index fe29ac7cc469..0f5c3e47423f 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -134,6 +134,18 @@ static inline unsigned int cpumask_first_and(const struct cpumask *srcp1,
 	return 0;
 }
 
+static inline unsigned int cpumask_first_one_and_zero(const struct cpumask *srcp1,
+					     const struct cpumask *srcp2)
+{
+	return 0;
+}
+
+static inline unsigned int cpumask_first_zero_and_zero(const struct cpumask *srcp1,
+					     const struct cpumask *srcp2)
+{
+	return 0;
+}
+
 static inline unsigned int cpumask_last(const struct cpumask *srcp)
 {
 	return 0;
@@ -157,6 +169,20 @@ static inline unsigned int cpumask_next_and(int n,
 	return n+1;
 }
 
+static inline unsigned int cpumask_next_one_and_zero(int n,
+					     const struct cpumask *srcp1,
+					     const struct cpumask *srcp2)
+{
+	return n+1;
+}
+
+static inline unsigned int cpumask_next_zero_and_zero(int n,
+					     const struct cpumask *srcp1,
+					     const struct cpumask *srcp2)
+{
+	return n+1;
+}
+
 static inline unsigned int cpumask_next_wrap(int n, const struct cpumask *mask,
 					     int start, bool wrap)
 {
@@ -230,6 +256,32 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask
 	return find_first_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits);
 }
 
+/**
+ * cpumask_first_one_and_zero - return the first cpu from *srcp1 & ~*srcp2
+ * @src1p: the first input
+ * @src2p: the second input
+ *
+ * Returns >= nr_cpu_ids if no cpus match in both.
+ */
+static inline
+unsigned int cpumask_first_one_and_zero(const struct cpumask *srcp1, const struct cpumask *srcp2)
+{
+	return find_first_one_and_zero_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits);
+}
+
+/**
+ * cpumask_first_zero_and_zero - return the first cpu from ~*srcp1 & ~*srcp2
+ * @src1p: the first input
+ * @src2p: the second input
+ *
+ * Returns >= nr_cpu_ids if no cpus match in both.
+ */
+static inline
+unsigned int cpumask_first_zero_and_zero(const struct cpumask *srcp1, const struct cpumask *srcp2)
+{
+	return find_first_zero_and_zero_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits);
+}
+
 /**
  * cpumask_last - get the last CPU in a cpumask
  * @srcp:	- the cpumask pointer
@@ -258,6 +310,40 @@ static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
 	return find_next_zero_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
 }
 
+/**
+ * cpumask_next_one_and_zero - return the next cpu from *srcp1 & ~*srcp2
+ * @n: the cpu prior to the place to search (ie. return will be > @n)
+ * @src1p: the first input
+ * @src2p: the second input
+ *
+ * Returns >= nr_cpu_ids if no cpus match in both.
+ */
+static inline
+unsigned int cpumask_next_one_and_zero(int n, const struct cpumask *srcp1, const struct cpumask *srcp2)
+{
+	/* -1 is a legal arg here. */
+	if (n != -1)
+		cpumask_check(n);
+	return find_next_one_and_zero_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits, n+1);
+}
+
+/**
+ * cpumask_next_zero_and_zero - return the next cpu from ~*srcp1 & ~*srcp2
+ * @n: the cpu prior to the place to search (ie. return will be > @n)
+ * @src1p: the first input
+ * @src2p: the second input
+ *
+ * Returns >= nr_cpu_ids if no cpus match in both.
+ */
+static inline
+unsigned int cpumask_next_zero_and_zero(int n, const struct cpumask *srcp1, const struct cpumask *srcp2)
+{
+	/* -1 is a legal arg here. */
+	if (n != -1)
+		cpumask_check(n);
+	return find_next_zero_and_zero_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits, n+1);
+}
+
 int __pure cpumask_next_and(int n, const struct cpumask *, const struct cpumask *);
 int __pure cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
 unsigned int cpumask_local_spread(unsigned int i, int node);
-- 
2.17.1