Linux 6.11: avoid passing "end" sentinel to register_sysctl()

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/
Closes #16400
This commit is contained in:
Rob Norris
2024-07-31 21:39:31 +10:00
committed by Tony Hutter
parent 8156099cf2
commit 8479a45abe
3 changed files with 66 additions and 3 deletions
+38 -3
View File
@@ -22,6 +22,9 @@
*
* Solaris Porting Layer (SPL) Proc Implementation.
*/
/*
* Copyright (c) 2024, Rob Norris <robn@despairlabs.com>
*/
#include <sys/systeminfo.h>
#include <sys/kstat.h>
@@ -694,6 +697,37 @@ static void spl_proc_cleanup(void)
}
}
#ifndef HAVE_REGISTER_SYSCTL_TABLE
/*
* Traditionally, struct ctl_table arrays have been terminated by an "empty"
* sentinel element (specifically, one with .procname == NULL).
*
* Linux 6.6 began migrating away from this, adding register_sysctl_sz() so
* that callers could provide the size directly, and redefining
* register_sysctl() to just call register_sysctl_sz() with the array size. It
* retained support for the terminating element so that existing callers would
* continue to work.
*
* Linux 6.11 removed support for the terminating element, instead interpreting
* it as a real malformed element, and rejecting it.
*
* In order to continue support older kernels, we retain the terminating
* sentinel element for our sysctl tables, but instead detect availability of
* register_sysctl_sz(). If it exists, we pass it the array size -1, stopping
* the kernel from trying to process the terminator. For pre-6.6 kernels that
* don't have register_sysctl_sz(), we just use register_sysctl(), which can
* handle the terminating element as it always has.
*/
#ifdef HAVE_REGISTER_SYSCTL_SZ
#define spl_proc_register_sysctl(p, t) \
register_sysctl_sz(p, t, ARRAY_SIZE(t)-1)
#else
#define spl_proc_register_sysctl(p, t) \
register_sysctl(p, t)
#endif
#endif
int
spl_proc_init(void)
{
@@ -704,16 +738,17 @@ spl_proc_init(void)
if (spl_header == NULL)
return (-EUNATCH);
#else
spl_header = register_sysctl("kernel/spl", spl_table);
spl_header = spl_proc_register_sysctl("kernel/spl", spl_table);
if (spl_header == NULL)
return (-EUNATCH);
spl_kmem = register_sysctl("kernel/spl/kmem", spl_kmem_table);
spl_kmem = spl_proc_register_sysctl("kernel/spl/kmem", spl_kmem_table);
if (spl_kmem == NULL) {
rc = -EUNATCH;
goto out;
}
spl_kstat = register_sysctl("kernel/spl/kstat", spl_kstat_table);
spl_kstat = spl_proc_register_sysctl("kernel/spl/kstat",
spl_kstat_table);
if (spl_kstat == NULL) {
rc = -EUNATCH;
goto out;