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[PATCH v2 1/7] cpumask: introduce cpumask_first_and_and()

Dawei Li posted 7 patches 1 year, 10 months ago
[PATCH v2 1/7] cpumask: introduce cpumask_first_and_and()
Posted by Dawei Li 1 year, 10 months ago 
Introduce cpumask_first_and_and() to get intersection between 3 cpumasks,
free of any intermediate cpumask variable. Instead, cpumask_first_and_and()
works in-place with all inputs and produce desired output directly.

Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
---
 include/linux/cpumask.h | 17 +++++++++++++++++
 include/linux/find.h    | 27 +++++++++++++++++++++++++++
 lib/find_bit.c          | 12 ++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 1c29947db848..c46f9e9e1d66 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -187,6 +187,23 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask
 	return find_first_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
 }
 
+/**
+ * cpumask_first_and_and - return the first cpu from *srcp1 & *srcp2 & *srcp3
+ * @srcp1: the first input
+ * @srcp2: the second input
+ * @srcp3: the third input
+ *
+ * Return: >= nr_cpu_ids if no cpus set in all.
+ */
+static inline
+unsigned int cpumask_first_and_and(const struct cpumask *srcp1,
+				   const struct cpumask *srcp2,
+				   const struct cpumask *srcp3)
+{
+	return find_first_and_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2),
+				      cpumask_bits(srcp3), small_cpumask_bits);
+}
+
 /**
  * cpumask_last - get the last CPU in a cpumask
  * @srcp:	- the cpumask pointer
diff --git a/include/linux/find.h b/include/linux/find.h
index c69598e383c1..28ec5a03393a 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -29,6 +29,8 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsign
 					unsigned long n);
 extern unsigned long _find_first_and_bit(const unsigned long *addr1,
 					 const unsigned long *addr2, unsigned long size);
+unsigned long _find_first_and_and_bit(const unsigned long *addr1, const unsigned long *addr2,
+				      const unsigned long *addr3, unsigned long size);
 extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);
 extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);
 
@@ -345,6 +347,31 @@ unsigned long find_first_and_bit(const unsigned long *addr1,
 }
 #endif
 
+/**
+ * find_first_and_and_bit - find the first set bit in 3 memory regions
+ * @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
+ *
+ * Returns the bit number for the first set bit
+ * If no bits are set, returns @size.
+ */
+static inline
+unsigned long find_first_and_and_bit(const unsigned long *addr1,
+				     const unsigned long *addr2,
+				     const unsigned long *addr3,
+				     unsigned long size)
+{
+	if (small_const_nbits(size)) {
+		unsigned long val = *addr1 & *addr2 & *addr3 & GENMASK(size - 1, 0);
+
+		return val ? __ffs(val) : size;
+	}
+
+	return _find_first_and_and_bit(addr1, addr2, addr3, size);
+}
+
 #ifndef find_first_zero_bit
 /**
  * find_first_zero_bit - find the first cleared bit in a memory region
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 32f99e9a670e..dacadd904250 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -116,6 +116,18 @@ unsigned long _find_first_and_bit(const unsigned long *addr1,
 EXPORT_SYMBOL(_find_first_and_bit);
 #endif
 
+/*
+ * Find the first set bit in three memory regions.
+ */
+unsigned long _find_first_and_and_bit(const unsigned long *addr1,
+				      const unsigned long *addr2,
+				      const unsigned long *addr3,
+				      unsigned long size)
+{
+	return FIND_FIRST_BIT(addr1[idx] & addr2[idx] & addr3[idx], /* nop */, size);
+}
+EXPORT_SYMBOL(_find_first_and_and_bit);
+
 #ifndef find_first_zero_bit
 /*
  * Find the first cleared bit in a memory region.
-- 
2.27.0
Re: [PATCH v2 1/7] cpumask: introduce cpumask_first_and_and()
Posted by Yury Norov 1 year, 10 months ago 
On Tue, Apr 16, 2024 at 04:54:48PM +0800, Dawei Li wrote:
> Introduce cpumask_first_and_and() to get intersection between 3 cpumasks,
> free of any intermediate cpumask variable. Instead, cpumask_first_and_and()
> works in-place with all inputs and produce desired output directly.
> 
> Signed-off-by: Dawei Li <dawei.li@shingroup.cn>

Acked-by: Yury Norov <yury.norov@gmail.com>

> ---
>  include/linux/cpumask.h | 17 +++++++++++++++++
>  include/linux/find.h    | 27 +++++++++++++++++++++++++++
>  lib/find_bit.c          | 12 ++++++++++++
>  3 files changed, 56 insertions(+)
> 
> diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> index 1c29947db848..c46f9e9e1d66 100644
> --- a/include/linux/cpumask.h
> +++ b/include/linux/cpumask.h
> @@ -187,6 +187,23 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask
>  	return find_first_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
>  }
>  
> +/**
> + * cpumask_first_and_and - return the first cpu from *srcp1 & *srcp2 & *srcp3
> + * @srcp1: the first input
> + * @srcp2: the second input
> + * @srcp3: the third input
> + *
> + * Return: >= nr_cpu_ids if no cpus set in all.
> + */
> +static inline
> +unsigned int cpumask_first_and_and(const struct cpumask *srcp1,
> +				   const struct cpumask *srcp2,
> +				   const struct cpumask *srcp3)
> +{
> +	return find_first_and_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2),
> +				      cpumask_bits(srcp3), small_cpumask_bits);
> +}
> +
>  /**
>   * cpumask_last - get the last CPU in a cpumask
>   * @srcp:	- the cpumask pointer
> diff --git a/include/linux/find.h b/include/linux/find.h
> index c69598e383c1..28ec5a03393a 100644
> --- a/include/linux/find.h
> +++ b/include/linux/find.h
> @@ -29,6 +29,8 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsign
>  					unsigned long n);
>  extern unsigned long _find_first_and_bit(const unsigned long *addr1,
>  					 const unsigned long *addr2, unsigned long size);
> +unsigned long _find_first_and_and_bit(const unsigned long *addr1, const unsigned long *addr2,
> +				      const unsigned long *addr3, unsigned long size);
>  extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);
>  extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);
>  
> @@ -345,6 +347,31 @@ unsigned long find_first_and_bit(const unsigned long *addr1,
>  }
>  #endif
>  
> +/**
> + * find_first_and_and_bit - find the first set bit in 3 memory regions
> + * @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
> + *
> + * Returns the bit number for the first set bit
> + * If no bits are set, returns @size.
> + */
> +static inline
> +unsigned long find_first_and_and_bit(const unsigned long *addr1,
> +				     const unsigned long *addr2,
> +				     const unsigned long *addr3,
> +				     unsigned long size)
> +{
> +	if (small_const_nbits(size)) {
> +		unsigned long val = *addr1 & *addr2 & *addr3 & GENMASK(size - 1, 0);
> +
> +		return val ? __ffs(val) : size;
> +	}
> +
> +	return _find_first_and_and_bit(addr1, addr2, addr3, size);
> +}
> +
>  #ifndef find_first_zero_bit
>  /**
>   * find_first_zero_bit - find the first cleared bit in a memory region
> diff --git a/lib/find_bit.c b/lib/find_bit.c
> index 32f99e9a670e..dacadd904250 100644
> --- a/lib/find_bit.c
> +++ b/lib/find_bit.c
> @@ -116,6 +116,18 @@ unsigned long _find_first_and_bit(const unsigned long *addr1,
>  EXPORT_SYMBOL(_find_first_and_bit);
>  #endif
>  
> +/*
> + * Find the first set bit in three memory regions.
> + */
> +unsigned long _find_first_and_and_bit(const unsigned long *addr1,
> +				      const unsigned long *addr2,
> +				      const unsigned long *addr3,
> +				      unsigned long size)
> +{
> +	return FIND_FIRST_BIT(addr1[idx] & addr2[idx] & addr3[idx], /* nop */, size);
> +}
> +EXPORT_SYMBOL(_find_first_and_and_bit);
> +
>  #ifndef find_first_zero_bit
>  /*
>   * Find the first cleared bit in a memory region.
> -- 
> 2.27.0
Re: [PATCH v2 1/7] cpumask: introduce cpumask_first_and_and()
Posted by Yury Norov 1 year, 10 months ago 
On Tue, Apr 16, 2024 at 10:45:54AM -0700, Yury Norov wrote:
> On Tue, Apr 16, 2024 at 04:54:48PM +0800, Dawei Li wrote:
> > Introduce cpumask_first_and_and() to get intersection between 3 cpumasks,
> > free of any intermediate cpumask variable. Instead, cpumask_first_and_and()
> > works in-place with all inputs and produce desired output directly.

Still there: s/produce/produces

But whatever. Also, I think this patch would better go with the rest
of the series, right?

> > 
> > Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
> 
> Acked-by: Yury Norov <yury.norov@gmail.com>
> 
> > ---
> >  include/linux/cpumask.h | 17 +++++++++++++++++
> >  include/linux/find.h    | 27 +++++++++++++++++++++++++++
> >  lib/find_bit.c          | 12 ++++++++++++
> >  3 files changed, 56 insertions(+)
> > 
> > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> > index 1c29947db848..c46f9e9e1d66 100644
> > --- a/include/linux/cpumask.h
> > +++ b/include/linux/cpumask.h
> > @@ -187,6 +187,23 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask
> >  	return find_first_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
> >  }
> >  
> > +/**
> > + * cpumask_first_and_and - return the first cpu from *srcp1 & *srcp2 & *srcp3
> > + * @srcp1: the first input
> > + * @srcp2: the second input
> > + * @srcp3: the third input
> > + *
> > + * Return: >= nr_cpu_ids if no cpus set in all.
> > + */
> > +static inline
> > +unsigned int cpumask_first_and_and(const struct cpumask *srcp1,
> > +				   const struct cpumask *srcp2,
> > +				   const struct cpumask *srcp3)
> > +{
> > +	return find_first_and_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2),
> > +				      cpumask_bits(srcp3), small_cpumask_bits);
> > +}
> > +
> >  /**
> >   * cpumask_last - get the last CPU in a cpumask
> >   * @srcp:	- the cpumask pointer
> > diff --git a/include/linux/find.h b/include/linux/find.h
> > index c69598e383c1..28ec5a03393a 100644
> > --- a/include/linux/find.h
> > +++ b/include/linux/find.h
> > @@ -29,6 +29,8 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsign
> >  					unsigned long n);
> >  extern unsigned long _find_first_and_bit(const unsigned long *addr1,
> >  					 const unsigned long *addr2, unsigned long size);
> > +unsigned long _find_first_and_and_bit(const unsigned long *addr1, const unsigned long *addr2,
> > +				      const unsigned long *addr3, unsigned long size);
> >  extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);
> >  extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);
> >  
> > @@ -345,6 +347,31 @@ unsigned long find_first_and_bit(const unsigned long *addr1,
> >  }
> >  #endif
> >  
> > +/**
> > + * find_first_and_and_bit - find the first set bit in 3 memory regions
> > + * @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
> > + *
> > + * Returns the bit number for the first set bit
> > + * If no bits are set, returns @size.
> > + */
> > +static inline
> > +unsigned long find_first_and_and_bit(const unsigned long *addr1,
> > +				     const unsigned long *addr2,
> > +				     const unsigned long *addr3,
> > +				     unsigned long size)
> > +{
> > +	if (small_const_nbits(size)) {
> > +		unsigned long val = *addr1 & *addr2 & *addr3 & GENMASK(size - 1, 0);
> > +
> > +		return val ? __ffs(val) : size;
> > +	}
> > +
> > +	return _find_first_and_and_bit(addr1, addr2, addr3, size);
> > +}
> > +
> >  #ifndef find_first_zero_bit
> >  /**
> >   * find_first_zero_bit - find the first cleared bit in a memory region
> > diff --git a/lib/find_bit.c b/lib/find_bit.c
> > index 32f99e9a670e..dacadd904250 100644
> > --- a/lib/find_bit.c
> > +++ b/lib/find_bit.c
> > @@ -116,6 +116,18 @@ unsigned long _find_first_and_bit(const unsigned long *addr1,
> >  EXPORT_SYMBOL(_find_first_and_bit);
> >  #endif
> >  
> > +/*
> > + * Find the first set bit in three memory regions.
> > + */
> > +unsigned long _find_first_and_and_bit(const unsigned long *addr1,
> > +				      const unsigned long *addr2,
> > +				      const unsigned long *addr3,
> > +				      unsigned long size)
> > +{
> > +	return FIND_FIRST_BIT(addr1[idx] & addr2[idx] & addr3[idx], /* nop */, size);
> > +}
> > +EXPORT_SYMBOL(_find_first_and_and_bit);
> > +
> >  #ifndef find_first_zero_bit
> >  /*
> >   * Find the first cleared bit in a memory region.
> > -- 
> > 2.27.0
Re: [PATCH v2 1/7] cpumask: introduce cpumask_first_and_and()
Posted by Dawei Li 1 year, 10 months ago 
Hi Yury,

Thanks for review.

On Tue, Apr 16, 2024 at 10:49:46AM -0700, Yury Norov wrote:
> On Tue, Apr 16, 2024 at 10:45:54AM -0700, Yury Norov wrote:
> > On Tue, Apr 16, 2024 at 04:54:48PM +0800, Dawei Li wrote:
> > > Introduce cpumask_first_and_and() to get intersection between 3 cpumasks,
> > > free of any intermediate cpumask variable. Instead, cpumask_first_and_and()
> > > works in-place with all inputs and produce desired output directly.
> 
> Still there: s/produce/produces

Oops, sorry for that. If it's needed I will respin v3. 

> 
> But whatever. Also, I think this patch would better go with the rest
> of the series, right?

I suppose so, this series should be applied as a whole.

> 
> > > 
> > > Signed-off-by: Dawei Li <dawei.li@shingroup.cn>

> > 
> > Acked-by: Yury Norov <yury.norov@gmail.com>

Thanks!

    Dawei
> > 
> > > ---
> > >  include/linux/cpumask.h | 17 +++++++++++++++++
> > >  include/linux/find.h    | 27 +++++++++++++++++++++++++++
> > >  lib/find_bit.c          | 12 ++++++++++++
> > >  3 files changed, 56 insertions(+)
> > > 
> > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> > > index 1c29947db848..c46f9e9e1d66 100644
> > > --- a/include/linux/cpumask.h
> > > +++ b/include/linux/cpumask.h
> > > @@ -187,6 +187,23 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask
> > >  	return find_first_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits);
> > >  }
> > >  
> > > +/**
> > > + * cpumask_first_and_and - return the first cpu from *srcp1 & *srcp2 & *srcp3
> > > + * @srcp1: the first input
> > > + * @srcp2: the second input
> > > + * @srcp3: the third input
> > > + *
> > > + * Return: >= nr_cpu_ids if no cpus set in all.
> > > + */
> > > +static inline
> > > +unsigned int cpumask_first_and_and(const struct cpumask *srcp1,
> > > +				   const struct cpumask *srcp2,
> > > +				   const struct cpumask *srcp3)
> > > +{
> > > +	return find_first_and_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2),
> > > +				      cpumask_bits(srcp3), small_cpumask_bits);
> > > +}
> > > +
> > >  /**
> > >   * cpumask_last - get the last CPU in a cpumask
> > >   * @srcp:	- the cpumask pointer
> > > diff --git a/include/linux/find.h b/include/linux/find.h
> > > index c69598e383c1..28ec5a03393a 100644
> > > --- a/include/linux/find.h
> > > +++ b/include/linux/find.h
> > > @@ -29,6 +29,8 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsign
> > >  					unsigned long n);
> > >  extern unsigned long _find_first_and_bit(const unsigned long *addr1,
> > >  					 const unsigned long *addr2, unsigned long size);
> > > +unsigned long _find_first_and_and_bit(const unsigned long *addr1, const unsigned long *addr2,
> > > +				      const unsigned long *addr3, unsigned long size);
> > >  extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);
> > >  extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);
> > >  
> > > @@ -345,6 +347,31 @@ unsigned long find_first_and_bit(const unsigned long *addr1,
> > >  }
> > >  #endif
> > >  
> > > +/**
> > > + * find_first_and_and_bit - find the first set bit in 3 memory regions
> > > + * @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
> > > + *
> > > + * Returns the bit number for the first set bit
> > > + * If no bits are set, returns @size.
> > > + */
> > > +static inline
> > > +unsigned long find_first_and_and_bit(const unsigned long *addr1,
> > > +				     const unsigned long *addr2,
> > > +				     const unsigned long *addr3,
> > > +				     unsigned long size)
> > > +{
> > > +	if (small_const_nbits(size)) {
> > > +		unsigned long val = *addr1 & *addr2 & *addr3 & GENMASK(size - 1, 0);
> > > +
> > > +		return val ? __ffs(val) : size;
> > > +	}
> > > +
> > > +	return _find_first_and_and_bit(addr1, addr2, addr3, size);
> > > +}
> > > +
> > >  #ifndef find_first_zero_bit
> > >  /**
> > >   * find_first_zero_bit - find the first cleared bit in a memory region
> > > diff --git a/lib/find_bit.c b/lib/find_bit.c
> > > index 32f99e9a670e..dacadd904250 100644
> > > --- a/lib/find_bit.c
> > > +++ b/lib/find_bit.c
> > > @@ -116,6 +116,18 @@ unsigned long _find_first_and_bit(const unsigned long *addr1,
> > >  EXPORT_SYMBOL(_find_first_and_bit);
> > >  #endif
> > >  
> > > +/*
> > > + * Find the first set bit in three memory regions.
> > > + */
> > > +unsigned long _find_first_and_and_bit(const unsigned long *addr1,
> > > +				      const unsigned long *addr2,
> > > +				      const unsigned long *addr3,
> > > +				      unsigned long size)
> > > +{
> > > +	return FIND_FIRST_BIT(addr1[idx] & addr2[idx] & addr3[idx], /* nop */, size);
> > > +}
> > > +EXPORT_SYMBOL(_find_first_and_and_bit);
> > > +
> > >  #ifndef find_first_zero_bit
> > >  /*
> > >   * Find the first cleared bit in a memory region.
> > > -- 
> > > 2.27.0
>
[tip: irq/core] cpumask: Introduce cpumask_first_and_and()
Posted by tip-bot2 for Dawei Li 1 year, 9 months ago 
The following commit has been merged into the irq/core branch of tip:

Commit-ID:     cdc66553c4130735f0a2db943a5259e54ff1597a
Gitweb:        https://git.kernel.org/tip/cdc66553c4130735f0a2db943a5259e54ff1597a
Author:        Dawei Li <dawei.li@shingroup.cn>
AuthorDate:    Tue, 16 Apr 2024 16:54:48 +08:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 24 Apr 2024 21:23:49 +02:00

cpumask: Introduce cpumask_first_and_and()

Introduce cpumask_first_and_and() to get intersection between 3 cpumasks,
free of any intermediate cpumask variable. Instead, cpumask_first_and_and()
works in-place with all inputs and produces desired output directly.

Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Yury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/r/20240416085454.3547175-2-dawei.li@shingroup.cn

---
 include/linux/cpumask.h | 17 +++++++++++++++++
 include/linux/find.h    | 27 +++++++++++++++++++++++++++
 lib/find_bit.c          | 12 ++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 1c29947..c46f9e9 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -188,6 +188,23 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask
 }
 
 /**
+ * cpumask_first_and_and - return the first cpu from *srcp1 & *srcp2 & *srcp3
+ * @srcp1: the first input
+ * @srcp2: the second input
+ * @srcp3: the third input
+ *
+ * Return: >= nr_cpu_ids if no cpus set in all.
+ */
+static inline
+unsigned int cpumask_first_and_and(const struct cpumask *srcp1,
+				   const struct cpumask *srcp2,
+				   const struct cpumask *srcp3)
+{
+	return find_first_and_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2),
+				      cpumask_bits(srcp3), small_cpumask_bits);
+}
+
+/**
  * cpumask_last - get the last CPU in a cpumask
  * @srcp:	- the cpumask pointer
  *
diff --git a/include/linux/find.h b/include/linux/find.h
index c69598e..28ec5a0 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -29,6 +29,8 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsign
 					unsigned long n);
 extern unsigned long _find_first_and_bit(const unsigned long *addr1,
 					 const unsigned long *addr2, unsigned long size);
+unsigned long _find_first_and_and_bit(const unsigned long *addr1, const unsigned long *addr2,
+				      const unsigned long *addr3, unsigned long size);
 extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);
 extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);
 
@@ -345,6 +347,31 @@ unsigned long find_first_and_bit(const unsigned long *addr1,
 }
 #endif
 
+/**
+ * find_first_and_and_bit - find the first set bit in 3 memory regions
+ * @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
+ *
+ * Returns the bit number for the first set bit
+ * If no bits are set, returns @size.
+ */
+static inline
+unsigned long find_first_and_and_bit(const unsigned long *addr1,
+				     const unsigned long *addr2,
+				     const unsigned long *addr3,
+				     unsigned long size)
+{
+	if (small_const_nbits(size)) {
+		unsigned long val = *addr1 & *addr2 & *addr3 & GENMASK(size - 1, 0);
+
+		return val ? __ffs(val) : size;
+	}
+
+	return _find_first_and_and_bit(addr1, addr2, addr3, size);
+}
+
 #ifndef find_first_zero_bit
 /**
  * find_first_zero_bit - find the first cleared bit in a memory region
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 32f99e9..dacadd9 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -116,6 +116,18 @@ unsigned long _find_first_and_bit(const unsigned long *addr1,
 EXPORT_SYMBOL(_find_first_and_bit);
 #endif
 
+/*
+ * Find the first set bit in three memory regions.
+ */
+unsigned long _find_first_and_and_bit(const unsigned long *addr1,
+				      const unsigned long *addr2,
+				      const unsigned long *addr3,
+				      unsigned long size)
+{
+	return FIND_FIRST_BIT(addr1[idx] & addr2[idx] & addr3[idx], /* nop */, size);
+}
+EXPORT_SYMBOL(_find_first_and_and_bit);
+
 #ifndef find_first_zero_bit
 /*
  * Find the first cleared bit in a memory region.

Patchew 2.1-devel-b67e4c2

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