From 31a4673c05ea942498a278d9dd519f251b501db1 Mon Sep 17 00:00:00 2001
From: Coleman Kane <ckane@colemankane.org>
Date: Wed, 2 Aug 2023 17:05:46 -0400
Subject: [PATCH] Linux 6.5 compat: register_sysctl_table removed
Additionally, the .child element of ctl_table has been removed in 6.5.
This change adds a new test for the pre-6.5 register_sysctl_table()
function, and uses the old code in that case. If it isn't found, then
the parentage entries in the tables are removed, and the register_sysctl
call is provided the paths of "kernel/spl", "kernel/spl/kmem", and
"kernel/spl/kstat" directly, to populate each subdirectory over three
calls, as is the new API.
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes #15138
---
config/kernel-register_sysctl_table.m4 | 27 ++++++++++++++++++++++++++
config/kernel.m4 | 2 ++
module/os/linux/spl/spl-proc.c | 26 ++++++++++++++++++++++---
3 files changed, 52 insertions(+), 3 deletions(-)
create mode 100644 config/kernel-register_sysctl_table.m4
diff --git a/config/kernel-register_sysctl_table.m4 b/config/kernel-register_sysctl_table.m4
new file mode 100644
index 0000000000..a5e934f56d
--- /dev/null
+++ b/config/kernel-register_sysctl_table.m4
@@ -0,0 +1,27 @@
+dnl #
+dnl # Linux 6.5 removes register_sysctl_table
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SRC_REGISTER_SYSCTL_TABLE], [
+ ZFS_LINUX_TEST_SRC([has_register_sysctl_table], [
+ #include <linux/sysctl.h>
+
+ static struct ctl_table dummy_table[] = {
+ {}
+ };
+
+ ],[
+ struct ctl_table_header *h
+ __attribute((unused)) = register_sysctl_table(dummy_table);
+ ])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_REGISTER_SYSCTL_TABLE], [
+ AC_MSG_CHECKING([whether register_sysctl_table exists])
+ ZFS_LINUX_TEST_RESULT([has_register_sysctl_table], [
+ AC_MSG_RESULT([yes])
+ AC_DEFINE(HAVE_REGISTER_SYSCTL_TABLE, 1,
+ [register_sysctl_table exists])
+ ],[
+ AC_MSG_RESULT([no])
+ ])
+])
diff --git a/config/kernel.m4 b/config/kernel.m4
index 1487fa2e77..28bd361d33 100644
--- a/config/kernel.m4
+++ b/config/kernel.m4
@@ -160,6 +160,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
ZFS_AC_KERNEL_SRC_FILEMAP
ZFS_AC_KERNEL_SRC_WRITEPAGE_T
ZFS_AC_KERNEL_SRC_RECLAIMED
+ ZFS_AC_KERNEL_SRC_REGISTER_SYSCTL_TABLE
case "$host_cpu" in
powerpc*)
ZFS_AC_KERNEL_SRC_CPU_HAS_FEATURE
@@ -299,6 +300,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
ZFS_AC_KERNEL_FILEMAP
ZFS_AC_KERNEL_WRITEPAGE_T
ZFS_AC_KERNEL_RECLAIMED
+ ZFS_AC_KERNEL_REGISTER_SYSCTL_TABLE
case "$host_cpu" in
powerpc*)
ZFS_AC_KERNEL_CPU_HAS_FEATURE
diff --git a/module/os/linux/spl/spl-proc.c b/module/os/linux/spl/spl-proc.c
index 01f5619e18..bcc356ae55 100644
--- a/module/os/linux/spl/spl-proc.c
+++ b/module/os/linux/spl/spl-proc.c
@@ -624,6 +624,7 @@ static struct ctl_table spl_table[] = {
.mode = 0644,
.proc_handler = &proc_dohostid,
},
+#ifdef HAVE_REGISTER_SYSCTL_TABLE
{
.procname = "kmem",
.mode = 0555,
@@ -634,9 +635,11 @@ static struct ctl_table spl_table[] = {
.mode = 0555,
.child = spl_kstat_table,
},
+#endif
{},
};
+#ifdef HAVE_REGISTER_SYSCTL_TABLE
static struct ctl_table spl_dir[] = {
{
.procname = "spl",
@@ -648,21 +651,38 @@ static struct ctl_table spl_dir[] = {
static struct ctl_table spl_root[] = {
{
- .procname = "kernel",
- .mode = 0555,
- .child = spl_dir,
+ .procname = "kernel",
+ .mode = 0555,
+ .child = spl_dir,
},
{}
};
+#endif
int
spl_proc_init(void)
{
int rc = 0;
+#ifdef HAVE_REGISTER_SYSCTL_TABLE
spl_header = register_sysctl_table(spl_root);
if (spl_header == NULL)
return (-EUNATCH);
+#else
+ spl_header = register_sysctl("kernel/spl", spl_table);
+ if (spl_header == NULL)
+ return (-EUNATCH);
+
+ if (register_sysctl("kernel/spl/kmem", spl_kmem_table) == NULL) {
+ rc = -EUNATCH;
+ goto out;
+ }
+
+ if (register_sysctl("kernel/spl/kstat", spl_kstat_table) == NULL) {
+ rc = -EUNATCH;
+ goto out;
+ }
+#endif
proc_spl = proc_mkdir("spl", NULL);
if (proc_spl == NULL) {