[RFC PATCH v1 12/57] cgroup: Remove PAGE_SIZE compile-time constant assumption

Ryan Roberts
2024-10-14T11:40:47Z

To prepare for supporting boot-time page size selection, refactor code
to remove assumptions about PAGE_SIZE being compile-time constant. Code
intended to be equivalent when compile-time page size is active.

Wrap global variables that are initialized with PAGE_SIZE derived values
using DEFINE_GLOBAL_PAGE_SIZE_VAR() so their initialization can be
deferred for boot-time page size builds.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---

***NOTE***
Any confused maintainers may want to read the cover note here for context:
https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/

kernel/cgroup/cgroup.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index c8e4b62b436a4..1e9c96210821d 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4176,16 +4176,16 @@ static int cgroup_seqfile_show(struct seq_file *m, void *arg)
return 0;
}

-static struct kernfs_ops cgroup_kf_single_ops = {
+static DEFINE_GLOBAL_PAGE_SIZE_VAR(struct kernfs_ops, cgroup_kf_single_ops, {
.atomic_write_len = PAGE_SIZE,
.open = cgroup_file_open,
.release = cgroup_file_release,
.write = cgroup_file_write,
.poll = cgroup_file_poll,
.seq_show = cgroup_seqfile_show,
-};
+});

-static struct kernfs_ops cgroup_kf_ops = {
+static DEFINE_GLOBAL_PAGE_SIZE_VAR(struct kernfs_ops, cgroup_kf_ops, {
.atomic_write_len = PAGE_SIZE,
.open = cgroup_file_open,
.release = cgroup_file_release,
@@ -4195,7 +4195,7 @@ static struct kernfs_ops cgroup_kf_ops = {
.seq_next = cgroup_seqfile_next,
.seq_stop = cgroup_seqfile_stop,
.seq_show = cgroup_seqfile_show,
-};
+});

static void cgroup_file_notify_timer(struct timer_list *timer)
{
--
2.43.0