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authorThomas Gleixner <tglx@linutronix.de>2019-07-22 20:47:24 +0200
committerThomas Gleixner <tglx@linutronix.de>2019-07-25 15:47:37 +0200
commitb9fa6442f7043e2cdd247905d4f3b80f2e9605cb (patch)
tree94f8a7ccb98e93e675a71730da84c8a77cf9389d
parente797bda3fd29137f6c151dfa10ea6a61c17895ce (diff)
cpumask: Implement cpumask_or_equal()
The IPI code of x86 needs to evaluate whether the target cpumask is equal to the cpu_online_mask or equal except for the calling CPU. To replace the current implementation which requires the usage of a temporary cpumask, which might involve allocations, add a new function which compares a cpumask to the result of two other cpumasks which are or'ed together before comparison. This allows to make the required decision in one go and the calling code then can check for the calling CPU being set in the target mask with cpumask_test_cpu(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20190722105220.585449120@linutronix.de
-rw-r--r--include/linux/bitmap.h23
-rw-r--r--include/linux/cpumask.h14
-rw-r--r--lib/bitmap.c20
3 files changed, 57 insertions, 0 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index f58e97446abc..90528f12bdfa 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -120,6 +120,10 @@ extern int __bitmap_empty(const unsigned long *bitmap, unsigned int nbits);
extern int __bitmap_full(const unsigned long *bitmap, unsigned int nbits);
extern int __bitmap_equal(const unsigned long *bitmap1,
const unsigned long *bitmap2, unsigned int nbits);
+extern bool __pure __bitmap_or_equal(const unsigned long *src1,
+ const unsigned long *src2,
+ const unsigned long *src3,
+ unsigned int nbits);
extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
unsigned int nbits);
extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
@@ -321,6 +325,25 @@ static inline int bitmap_equal(const unsigned long *src1,
return __bitmap_equal(src1, src2, nbits);
}
+/**
+ * bitmap_or_equal - Check whether the or of two bitnaps is equal to a third
+ * @src1: Pointer to bitmap 1
+ * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1
+ * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
+ *
+ * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
+ */
+static inline bool bitmap_or_equal(const unsigned long *src1,
+ const unsigned long *src2,
+ const unsigned long *src3,
+ unsigned int nbits)
+{
+ if (!small_const_nbits(nbits))
+ return __bitmap_or_equal(src1, src2, src3, nbits);
+
+ return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
+}
+
static inline int bitmap_intersects(const unsigned long *src1,
const unsigned long *src2, unsigned int nbits)
{
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 693124900f0a..0c7db5efe66c 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -476,6 +476,20 @@ static inline bool cpumask_equal(const struct cpumask *src1p,
}
/**
+ * cpumask_or_equal - *src1p | *src2p == *src3p
+ * @src1p: the first input
+ * @src2p: the second input
+ * @src3p: the third input
+ */
+static inline bool cpumask_or_equal(const struct cpumask *src1p,
+ const struct cpumask *src2p,
+ const struct cpumask *src3p)
+{
+ return bitmap_or_equal(cpumask_bits(src1p), cpumask_bits(src2p),
+ cpumask_bits(src3p), nr_cpumask_bits);
+}
+
+/**
* cpumask_intersects - (*src1p & *src2p) != 0
* @src1p: the first input
* @src2p: the second input
diff --git a/lib/bitmap.c b/lib/bitmap.c
index bbe2589e8497..f9e834841e94 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -59,6 +59,26 @@ int __bitmap_equal(const unsigned long *bitmap1,
}
EXPORT_SYMBOL(__bitmap_equal);
+bool __bitmap_or_equal(const unsigned long *bitmap1,
+ const unsigned long *bitmap2,
+ const unsigned long *bitmap3,
+ unsigned int bits)
+{
+ unsigned int k, lim = bits / BITS_PER_LONG;
+ unsigned long tmp;
+
+ for (k = 0; k < lim; ++k) {
+ if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
+ return false;
+ }
+
+ if (!(bits % BITS_PER_LONG))
+ return true;
+
+ tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
+ return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
+}
+
void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
{
unsigned int k, lim = BITS_TO_LONGS(bits);