cpumask: Introduce for_each_cpu_andnot()

for_each_cpu_and() is very convenient as it saves having to allocate a
temporary cpumask to store the result of cpumask_and(). The same issue
applies to cpumask_andnot() which doesn't actually need temporary storage
for iteration purposes.

Following what has been done for for_each_cpu_and(), introduce
for_each_cpu_andnot().

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
This commit is contained in:
Valentin Schneider 2022-10-03 16:34:18 +01:00 committed by Yury Norov
parent 90d482908e
commit 5f75ff295c
2 changed files with 23 additions and 0 deletions

View File

@ -306,6 +306,24 @@ unsigned int __pure cpumask_next_wrap(int n, const struct cpumask *mask, int sta
#define for_each_cpu_and(cpu, mask1, mask2) \
for_each_and_bit(cpu, cpumask_bits(mask1), cpumask_bits(mask2), nr_cpumask_bits)
/**
* for_each_cpu_andnot - iterate over every cpu present in one mask, excluding
* those present in another.
* @cpu: the (optionally unsigned) integer iterator
* @mask1: the first cpumask pointer
* @mask2: the second cpumask pointer
*
* This saves a temporary CPU mask in many places. It is equivalent to:
* struct cpumask tmp;
* cpumask_andnot(&tmp, &mask1, &mask2);
* for_each_cpu(cpu, &tmp)
* ...
*
* After the loop, cpu is >= nr_cpu_ids.
*/
#define for_each_cpu_andnot(cpu, mask1, mask2) \
for_each_andnot_bit(cpu, cpumask_bits(mask1), cpumask_bits(mask2), nr_cpumask_bits)
/**
* cpumask_any_but - return a "random" in a cpumask, but not this one.
* @mask: the cpumask to search

View File

@ -498,6 +498,11 @@ unsigned long find_next_bit_le(const void *addr, unsigned
(bit) = find_next_and_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
(bit)++)
#define for_each_andnot_bit(bit, addr1, addr2, size) \
for ((bit) = 0; \
(bit) = find_next_andnot_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
(bit)++)
/* same as for_each_set_bit() but use bit as value to start with */
#define for_each_set_bit_from(bit, addr, size) \
for (; (bit) = find_next_bit((addr), (size), (bit)), (bit) < (size); (bit)++)