On Wed, 2020-12-30 at 12:13 +0800, Peng Wang wrote:
> Some max_length wants to hold as large room as possible to
> ensure enough size to tackle with the biggest NR_CPUS. As
> an example below:
>
> kernel/cgroup/cpuset.c:
> static struct cftype legacy_files[] = {
> {
> .name = "cpus",
> .seq_show = cpuset_common_seq_show,
> .write = cpuset_write_resmask,
> .max_write_len = (100U + 6 * NR_CPUS),
> .private = FILE_CPULIST,
> },
> ...
> }
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -7022,12 +7022,15 @@ sub process {
>
>
> # use of NR_CPUS is usually wrong
> # ignore definitions of NR_CPUS and usage to define arrays as likely right
> +# ignore designated initializers using NR_CPUS
> +
> if ($line =~ /\bNR_CPUS\b/ &&
> $line !~ /^.\s*\s*#\s*if\b.*\bNR_CPUS\b/ &&
> $line !~ /^.\s*\s*#\s*define\b.*\bNR_CPUS\b/ &&
> $line !~ /^.\s*$Declare\s.*\[[^\]]*NR_CPUS[^\]]*\]/ &&
> $line !~ /\[[^\]]*\.\.\.[^\]]*NR_CPUS[^\]]*\]/ &&
> - $line !~ /\[[^\]]*NR_CPUS[^\]]*\.\.\.[^\]]*\]/)
> + $line !~ /\[[^\]]*NR_CPUS[^\]]*\.\.\.[^\]]*\]/ &&
> + $line !~ /\s*\..*=.*\bNR_CPUS\b.*,$/)
> {
> WARN("NR_CPUS",
> "usage of NR_CPUS is often wrong - consider using
> cpu_possible(), num_possible_cpus(), for_each_possible_cpu(), etc\n" .
> $herecurr);
I wonder if it's worth it as there just aren't many of these: (6 total)
$ git grep -P '\..*=.*\bNR_CPUS\b.*,\s*$'
drivers/firmware/efi/efi.c: .cpu_bitmap = {
[BITS_TO_LONGS(NR__CPUS)] = 0},
drivers/infiniband/hw/hfi1/sdma.c: .max_size = NR_CPUS,
init/init_task.c: .nr_cpus_allowed= NR_CPUS,
kernel/cgroup/cpuset.c: .max_write_len = (100U + 6 * NR_CPUS),
kernel/cgroup/cpuset.c: .max_write_len = (100U + 6 * NR_CPUS),
kernel/sysctl.c: .maxlen = NR_CPUS,
It also seems it might be more sensible as:
$line !~ /^.\s*\.\w+\s*=\s*.*\bNR_CPUS\b/
Which finds a couple more:
$ git grep -P '^\s*\.\w+\s*=\s*.*\bNR_CPUS\b'
arch/arm64/include/asm/processor.h: .fpsimd_cpu = NR_CPUS,
\
arch/powerpc/kernel/prom_init.c: .max_cpus =
cpu_to_be32(NR_CPUS), /* number of cores supported */
drivers/firmware/efi/efi.c: .cpu_bitmap = {
[BITS_TO_LONGS(NR_CPUS)] = 0},
drivers/infiniband/hw/hfi1/sdma.c: .max_size = NR_CPUS,
init/init_task.c: .nr_cpus_allowed= NR_CPUS,
kernel/cgroup/cpuset.c: .max_write_len = (100U + 6 * NR_CPUS),
kernel/cgroup/cpuset.c: .max_write_len = (100U + 6 * NR_CPUS),
kernel/sysctl.c: .maxlen = NR_CPUS,
