From: Yury Norov <yury.norov@gmail.com>
Date: Tue, 28 Jan 2025 16:46:35 +0000 (-0500)
Subject: cpumask: re-introduce cpumask_next{,_and}_wrap()
X-Git-Tag: v6.15-rc1~222^2~13
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3268cb2e49cc2a2d142f210efdc82602639d2047;p=thirdparty%2Fkernel%2Flinux.git

cpumask: re-introduce cpumask_next{,_and}_wrap()

cpumask_next_wrap_old() has two additional parameters, comparing to its
generic counterpart find_next_bit_wrap(). The reason for that is
historical.

Before 4fe49b3b97c262 ("lib/bitmap: introduce for_each_set_bit_wrap()
macro"), cpumask_next_wrap() was used to implement for_each_cpu_wrap()
iterator. Now that the iterator is an alias to generic
for_each_set_bit_wrap(), the additional parameters aren't used and may
confuse readers.

All existing users call cpumask_next_wrap() in a way that makes it
possible to turn it to straight and simple alias to find_next_bit_wrap().

In a couple of places kernel users opencode missing cpumask_next_and_wrap().
Add it as well.

CC: Alexander Gordeev <agordeev@linux.ibm.com>
CC: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
---

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 7f7f17cfd21d5..87d9784e009d4 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -284,6 +284,44 @@ unsigned int cpumask_next_and(int n, const struct cpumask *src1p,
 		small_cpumask_bits, n + 1);
 }
 
+/**
+ * cpumask_next_and_wrap - get the next cpu in *src1p & *src2p, starting from
+ *			   @n+1. If nothing found, wrap around and start from
+ *			   the beginning
+ * @n: the cpu prior to the place to search (i.e. search starts from @n+1)
+ * @src1p: the first cpumask pointer
+ * @src2p: the second cpumask pointer
+ *
+ * Return: next set bit, wrapped if needed, or >= nr_cpu_ids if @src1p & @src2p is empty.
+ */
+static __always_inline
+unsigned int cpumask_next_and_wrap(int n, const struct cpumask *src1p,
+			      const struct cpumask *src2p)
+{
+	/* -1 is a legal arg here. */
+	if (n != -1)
+		cpumask_check(n);
+	return find_next_and_bit_wrap(cpumask_bits(src1p), cpumask_bits(src2p),
+		small_cpumask_bits, n + 1);
+}
+
+/**
+ * cpumask_next_wrap - get the next cpu in *src, starting from @n+1. If nothing
+ *		       found, wrap around and start from the beginning
+ * @n: the cpu prior to the place to search (i.e. search starts from @n+1)
+ * @src: cpumask pointer
+ *
+ * Return: next set bit, wrapped if needed, or >= nr_cpu_ids if @src is empty.
+ */
+static __always_inline
+unsigned int cpumask_next_wrap(int n, const struct cpumask *src)
+{
+	/* -1 is a legal arg here. */
+	if (n != -1)
+		cpumask_check(n);
+	return find_next_bit_wrap(cpumask_bits(src), small_cpumask_bits, n + 1);
+}
+
 /**
  * for_each_cpu - iterate over every cpu in a mask
  * @cpu: the (optionally unsigned) integer iterator