From: Eric W. Biederman Date: Thu, 9 Nov 2006 01:44:51 +0000 (-0800) Subject: [PATCH] sysctl: Undeprecate sys_sysctl X-Git-Tag: v2.6.19-rc6~51 X-Git-Url: http://git.samba.org/samba.git/?p=sfrench%2Fcifs-2.6.git;a=commitdiff_plain;h=13bb7e37e5081d03643e2bd64f3f5d21f32e7221 [PATCH] sysctl: Undeprecate sys_sysctl The basic issue is that despite have been deprecated and warned about as a very bad thing in the man pages since its inception there are a few real users of sys_sysctl. It was my assumption that because sysctl had been deprecated for all of 2.6 there would be no user space users by this point, so I initially gave sys_sysctl a very short deprecation period. Now that I know there are a few real users the only sane way to proceed with deprecation is to push the time limit out to a year or two work and work with distributions that have big testing pools like fedora core to find these last remaining users. Which means that the sys_sysctl interface needs to be maintained in the meantime. Since I have provided a technical measure that allows us to add new sysctl entries without reserving more binary numbers I believe that is enough to fix the sys_sysctl binary interface maintenance problems, because there is no longer a need to change the binary interface at all. Since the sys_sysctl implementation needs to stay around for a while and the worst of the maintenance issues that caused us to occasionally break the ABI have been addressed I don't see any advantage in continuing with the removal of sys_sysctl. So instead of merely increasing the deprecation period this patch removes the deprecation of sys_sysctl and modifies the kernel to compile the code in by default. With committing to maintain sys_sysctl we get all of the advantages of a fast interface for anything that needs it. Currently sys_sysctl is about 5x faster than /proc/sys, for the same string data. Signed-off-by: Eric W. Biederman Acked-by: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 1ac3c74646e3..d52c4aaaf17f 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -53,18 +53,6 @@ Who: Mauro Carvalho Chehab --------------------------- -What: sys_sysctl -When: January 2007 -Why: The same information is available through /proc/sys and that is the - interface user space prefers to use. And there do not appear to be - any existing user in user space of sys_sysctl. The additional - maintenance overhead of keeping a set of binary names gets - in the way of doing a good job of maintaining this interface. - -Who: Eric Biederman - ---------------------------- - What: PCMCIA control ioctl (needed for pcmcia-cs [cardmgr, cardctl]) When: November 2005 Files: drivers/pcmcia/: pcmcia_ioctl.c diff --git a/init/Kconfig b/init/Kconfig index c8b2624af176..176f7e5136c7 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -304,20 +304,19 @@ config UID16 config SYSCTL_SYSCALL bool "Sysctl syscall support" if EMBEDDED - default n + default y select SYSCTL ---help--- - Enable the deprecated sysctl system call. sys_sysctl uses - binary paths that have been found to be a major pain to maintain - and use. The interface in /proc/sys is now the primary and what - everyone uses. + sys_sysctl uses binary paths that have been found challenging + to properly maintain and use. The interface in /proc/sys + using paths with ascii names is now the primary path to this + information. - Nothing has been using the binary sysctl interface for some - time now so nothing should break if you disable sysctl syscall - support, and your kernel will get marginally smaller. + Almost nothing using the binary sysctl interface so if you are + trying to save some space it is probably safe to disable this, + making your kernel marginally smaller. - Unless you have an application that uses the sys_sysctl interface - you should probably say N here. + If unsure say Y here. config KALLSYMS bool "Load all symbols for debugging/kksymoops" if EMBEDDED