[PATCH] sysctl: implement CTL_UNNUMBERED

This patch takes the CTL_UNNUMBERD concept from NFS and makes it available to
all new sysctl users.

At the same time the sysctl binary interface maintenance documentation is
updated to mention and to describe what is needed to successfully maintain the
sysctl binary interface.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 634139232aafae89c3e14b9ceaf7fa8ee13e5bd2..8ca18085e68d0e796d0089b3b932aabddf835d3f 100644 (file)
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -353,9 +353,6 @@ EXPORT_SYMBOL(lockd_down);
  * Sysctl parameters (same as module parameters, different interface).
  */
 
-/* Something that isn't CTL_ANY, CTL_NONE or a value that may clash. */
-#define CTL_UNNUMBERED         -2
-
 static ctl_table nlm_sysctls[] = {
        {
                .ctl_name       = CTL_UNNUMBERED,

diff --git a/fs/nfs/sysctl.c b/fs/nfs/sysctl.c
index 2fe3403c24094bce4973b0f1b52b2cc26e760f0a..3ea50ac648209dc28ad6ed1aa632f3a9f0df1ff9 100644 (file)
--- a/fs/nfs/sysctl.c
+++ b/fs/nfs/sysctl.c
@@ -18,11 +18,6 @@
 static const int nfs_set_port_min = 0;
 static const int nfs_set_port_max = 65535;
 static struct ctl_table_header *nfs_callback_sysctl_table;
-/*
- * Something that isn't CTL_ANY, CTL_NONE or a value that may clash.
- * Use the same values as fs/lockd/svc.c
- */
-#define CTL_UNNUMBERED -2
 
 static ctl_table nfs_cb_sysctls[] = {
 #ifdef CONFIG_NFS_V4

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index c184732a70fcc97f475be2cfef6bcf61ef35e7c8..d98562f1df76588ad154fc552dc81fba7ef180ad 100644 (file)
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -6,10 +6,17 @@
  ****************************************************************
  ****************************************************************
  **
+ **  WARNING:
  **  The values in this file are exported to user space via 
- **  the sysctl() binary interface.  However this interface
- **  is unstable and deprecated and will be removed in the future. 
- **  For a stable interface use /proc/sys.
+ **  the sysctl() binary interface.  Do *NOT* change the
+ **  numbering of any existing values here, and do not change
+ **  any numbers within any one set of values.  If you have to
+ **  have to redefine an existing interface, use a new number for it.
+ **  The kernel will then return -ENOTDIR to any application using
+ **  the old binary interface.
+ **
+ **  For new interfaces unless you really need a binary number
+ **  please use CTL_UNNUMBERED.
  **
  ****************************************************************
  ****************************************************************
@@ -48,6 +55,7 @@ struct __sysctl_args {
 #ifdef __KERNEL__
 #define CTL_ANY                -1      /* Matches any name */
 #define CTL_NONE       0
+#define CTL_UNNUMBERED CTL_NONE        /* sysctl without a binary number */
 #endif
 
 enum