From 2248ccd80124e61c2c84a22b22409bab452e1f0c Mon Sep 17 00:00:00 2001 From: Sander Vanheule Date: Tue, 9 Aug 2022 19:36:34 +0200 Subject: lib/cpumask: add inline cpumask_next_wrap() for UP In the uniprocessor case, cpumask_next_wrap() can be simplified, as the number of valid argument combinations is limited: - 'start' can only be 0 - 'n' can only be -1 or 0 The only valid CPU that can then be returned, if any, will be the first one set in the provided 'mask'. For NR_CPUS == 1, include/linux/cpumask.h now provides an inline definition of cpumask_next_wrap(), which will conflict with the one provided by lib/cpumask.c. Make building of lib/cpumask.o again depend on CONFIG_SMP=y (i.e. NR_CPUS > 1) to avoid the re-definition. Suggested-by: Yury Norov Signed-off-by: Sander Vanheule Signed-off-by: Yury Norov --- include/linux/cpumask.h | 19 +++++++++++++++++++ lib/Makefile | 3 ++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index d8c2a40f8beb..bd047864c7ac 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -262,7 +262,26 @@ unsigned int cpumask_next_and(int n, const struct cpumask *src1p, (cpu) = cpumask_next_zero((cpu), (mask)), \ (cpu) < nr_cpu_ids;) +#if NR_CPUS == 1 +static inline +unsigned int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap) +{ + cpumask_check(start); + if (n != -1) + cpumask_check(n); + + /* + * Return the first available CPU when wrapping, or when starting before cpu0, + * since there is only one valid option. + */ + if (wrap && n >= 0) + return nr_cpumask_bits; + + return cpumask_first(mask); +} +#else unsigned int __pure cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap); +#endif /** * for_each_cpu_wrap - iterate over every cpu in a mask, starting at a specified location diff --git a/lib/Makefile b/lib/Makefile index c95212141928..5927d7fa0806 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -34,9 +34,10 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ nmi_backtrace.o win_minmax.o memcat_p.o \ - buildid.o cpumask.o + buildid.o lib-$(CONFIG_PRINTK) += dump_stack.o +lib-$(CONFIG_SMP) += cpumask.o lib-y += kobject.o klist.o obj-y += lockref.o -- cgit v1.2.3