[PATCH 3/8] sysctl: Remove check for sentinel element in ctl_table arrays

From: Joel Granados via B4 Relay
Date: Tue Jun 04 2024 - 02:32:22 EST


From: Joel Granados <j.granados@xxxxxxxxxxx>

Use ARRAY_SIZE exclusively by removing the check to ->procname in the
stopping criteria of the loops traversing ctl_table arrays. This commit
finalizes the removal of the sentinel elements at the end of ctl_table
arrays which reduces the build time size and run time memory bloat by
~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@xxxxxxxxxxxxxxxxxxxxxx/)

Remove the entry->procname evaluation from the for loop stopping
criteria in sysctl and sysctl_net.

Signed-off-by: Joel Granados <j.granados@xxxxxxxxxxx>
---
fs/proc/proc_sysctl.c | 2 +-
net/sysctl_net.c | 11 ++---------
2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index b1c2c0b82116..d4ba7ad9dbe0 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -21,7 +21,7 @@

#define list_for_each_table_entry(entry, header) \
entry = header->ctl_table; \
- for (size_t i = 0 ; i < header->ctl_table_size && entry->procname; ++i, entry++)
+ for (size_t i = 0 ; i < header->ctl_table_size; ++i, entry++)

static const struct dentry_operations proc_sys_dentry_operations;
static const struct file_operations proc_sys_file_operations;
diff --git a/net/sysctl_net.c b/net/sysctl_net.c
index f5017012a049..19e8048241ba 100644
--- a/net/sysctl_net.c
+++ b/net/sysctl_net.c
@@ -127,7 +127,7 @@ static void ensure_safe_net_sysctl(struct net *net, const char *path,

pr_debug("Registering net sysctl (net %p): %s\n", net, path);
ent = table;
- for (size_t i = 0; i < table_size && ent->procname; ent++, i++) {
+ for (size_t i = 0; i < table_size; ent++, i++) {
unsigned long addr;
const char *where;

@@ -165,17 +165,10 @@ struct ctl_table_header *register_net_sysctl_sz(struct net *net,
struct ctl_table *table,
size_t table_size)
{
- int count;
- struct ctl_table *entry;
-
if (!net_eq(net, &init_net))
ensure_safe_net_sysctl(net, path, table, table_size);

- entry = table;
- for (count = 0 ; count < table_size && entry->procname; entry++, count++)
- ;
-
- return __register_sysctl_table(&net->sysctls, path, table, count);
+ return __register_sysctl_table(&net->sysctls, path, table, table_size);
}
EXPORT_SYMBOL_GPL(register_net_sysctl_sz);


--
2.43.0