| Message ID | 20241228184949.31582-7-yury.norov@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Krzysztof Wilczyński |
| Headers | show |
| Series | cpumask: cleanup cpumask_next_wrap() implementation and usage | expand |
On Sat, Dec 28, 2024 at 10:49:38AM -0800, Yury Norov wrote: > cpumask_next_wrap_old() has two additional parameters, comparing to it's > analogue in linux/find.h find_next_bit_wrap(). The reason for that is > historical. s/it's/its/ Personally I think cscope/tags/git grep make "find_next_bit_wrap()" enough even without mentioning "linux/find.h". > + * cpumask_next_and_wrap - get the next cpu in *src1p & *src2p, starting from > + * @n and wrapping around, if needed > + * @n: the cpu prior to the place to search (i.e. return will be > @n) Is the return really > @n if it wraps?
On Sat, Dec 28, 2024 at 10:49:38AM -0800, Yury Norov wrote: Hi Yury, > cpumask_next_wrap_old() has two additional parameters, comparing to it's > analogue in linux/find.h 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 places kernel users opencode missing cpumask_next_and_wrap(). > Add it as well. > > Signed-off-by: Yury Norov <yury.norov@gmail.com> > --- > include/linux/cpumask.h | 37 +++++++++++++++++++++++++++++++++++++ > 1 file changed, 37 insertions(+) > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > index b267a4f6a917..18c9908d50c4 100644 > --- a/include/linux/cpumask.h > +++ b/include/linux/cpumask.h > @@ -284,6 +284,43 @@ 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 and wrapping around, if needed > + * @n: the cpu prior to the place to search (i.e. return will be > @n) > + * @src1p: the first cpumask pointer > + * @src2p: the second cpumask pointer > + * > + * Return: >= nr_cpu_ids if no further cpus set in both. > + */ > +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 and wrapping around, if needed Does it mean the search wraps a cpumask and starts from the beginning if the bit is not found and returns >= nr_cpu_ids if @n crosses itself? > + * @n: the cpu prior to the place to search > + * @src: cpumask pointer > + * > + * Return: >= nr_cpu_ids if no further cpus set in both. It looks like Return is a cpumask_next_and_wrap() comment leftover. > + */ > +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 Thanks!
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index b267a4f6a917..18c9908d50c4 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -284,6 +284,43 @@ 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 and wrapping around, if needed + * @n: the cpu prior to the place to search (i.e. return will be > @n) + * @src1p: the first cpumask pointer + * @src2p: the second cpumask pointer + * + * Return: >= nr_cpu_ids if no further cpus set in both. + */ +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 and wrapping around, if needed + * @n: the cpu prior to the place to search + * @src: cpumask pointer + * + * Return: >= nr_cpu_ids if no further cpus set in both. + */ +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
cpumask_next_wrap_old() has two additional parameters, comparing to it's analogue in linux/find.h 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 places kernel users opencode missing cpumask_next_and_wrap(). Add it as well. Signed-off-by: Yury Norov <yury.norov@gmail.com> --- include/linux/cpumask.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+)