[RFC PATCH 30/31] fs/resctrl: Fix excessive padding in schemata output

[Chen Yu]

When a resource has several controls (such as the region-aware MBA
controls), the schemata and size files pad every line with a large
amount of leading whitespace and the control names no longer line up
into a table.

Compute the column width from the longest single control name and format
the full control name within that width so the output is aligned again.

Reported-by: Tony Luck <luck.tony@xxxxxxxxx>
Link: https://lore.kernel.org/all/aiB2oJFPF-sqUVQx@agluck-desk3/
Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
---
 fs/resctrl/ctrlmondata.c | 19 +++++++++++--------
 fs/resctrl/rdtgroup.c    | 11 ++++++-----
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index d65036f7079e..66483c83e99d 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -405,16 +405,16 @@ static struct resctrl_ctrl *resctrl_resource_ctrl_get(struct rdt_resource *r,
 size_t resctrl_resource_ctrl_max_len(struct rdt_resource *r)
 {
 	struct resctrl_ctrl *ctrl;
-	size_t total = 0;
+	size_t max = 0;
 	size_t len;
 
 	for_each_resource_ctrl(ctrl,r) {
 		len = strlen(resctrl_ctrl_name_str(ctrl->name));
 		if (len)
-			total += 1 + len;
+			max = max_t(size_t, max, 1 + len);
 	}
 
-	return total;
+	return max;
 }
 
 static int rdtgroup_parse_ctrl(char *ctrlname, char *tok,
@@ -522,6 +522,7 @@ static void show_doms(struct seq_file *s, struct rdt_resource_final *f,
 		      bool print_ctrl, int closid, struct resctrl_ctrl *ctrl)
 {
 	struct rdt_resource *r = f->res;
+	char ctrl_full_name[20];
 	struct rdt_ctrl_domain *dom;
 	bool sep = false;
 	u32 ctrl_val;
@@ -529,11 +530,13 @@ static void show_doms(struct seq_file *s, struct rdt_resource_final *f,
 	/* Walking r->domains, ensure it can't race with cpuhp */
 	lockdep_assert_cpus_held();
 
-	if (print_ctrl)
-		seq_printf(s, "%*s%s%s:", max_name_width, f->name,
-				resctrl_ctrl_is_default(ctrl) ? "" : "_",
-				resctrl_ctrl_is_default(ctrl) ?
-				 "" : resctrl_ctrl_name_str(ctrl->name));
+	if (print_ctrl) {
+		snprintf(ctrl_full_name, sizeof(ctrl_full_name), "%s%s%s", f->name,
+			 resctrl_ctrl_is_default(ctrl) ? "" : "_",
+			 resctrl_ctrl_is_default(ctrl) ?
+			  "" : resctrl_ctrl_name_str(ctrl->name));
+		seq_printf(s, "%*s:", max_name_width, ctrl_full_name);
+	}
 	list_for_each_entry(dom, &ctrl->domains, hdr.list) {
 		if (sep)
 			seq_puts(s, ";");
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 31bea5a9833b..7d615502a892 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1653,6 +1653,7 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
 	struct resctrl_ctrl *ctrl;
 	struct rdtgroup *rdtgrp;
 	struct rdt_resource *r;
+	char ctrl_full_name[20];
 	unsigned int size;
 	u32 ctrl_val;
 	int ret = 0;
@@ -1693,11 +1694,11 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
 		type = f->conf_type;
 		for_each_resource_ctrl(ctrl, r) {
 			sep = false;
-			seq_printf(s, "%*s", max_name_width, f->name);
-			if (!resctrl_ctrl_is_default(ctrl))
-				seq_printf(s, "_%s:", resctrl_ctrl_name_str(ctrl->name));
-			else
-				seq_putc(s, ':');
+			snprintf(ctrl_full_name, sizeof(ctrl_full_name), "%s%s%s", f->name,
+				 resctrl_ctrl_is_default(ctrl) ? "" : "_",
+				 resctrl_ctrl_is_default(ctrl) ?
+				  "" : resctrl_ctrl_name_str(ctrl->name));
+			seq_printf(s, "%*s:", max_name_width, ctrl_full_name);
 			list_for_each_entry(d, &ctrl->domains, hdr.list) {
 				if (sep)
 					seq_putc(s, ';');
-- 
2.43.0