Commit 2248ccd8 authored by Sander Vanheule's avatar Sander Vanheule Committed by Yury Norov
Browse files

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: default avatarYury Norov <yury.norov@gmail.com>
Signed-off-by: default avatarSander Vanheule <sander@svanheule.net>
Signed-off-by: default avatarYury Norov <yury.norov@gmail.com>
parent be599244

include/linux/cpumask.h

+19 −0
Original line number Diff line number Diff line
@@ -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

lib/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -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