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  1. 21 Oct, 2008 6 commits
    • Rusty Russell's avatar
      core_param() for genuinely core kernel parameters · 67e67cea
      Rusty Russell authored 
      There are a lot of one-liner uses of __setup() in the kernel: they're
cumbersome and not queryable (definitely not settable) via /sys.  Yet
it's ugly to simplify them to module_param(), because by default that
inserts a prefix of the module name (usually filename).

So, introduce a "core_param".  The parameter gets no prefix, but
appears in /sys/module/kernel/parameters/ (if non-zero perms arg).  I
thought about using the name "core", but that's more common than
"kernel".  And if you create a module called "kernel", you will die
a horrible death.
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      67e67cea
    • Rusty Russell's avatar
      param: Fix duplicate module prefixes · 9b473de8
      Rusty Russell authored 
      Instead of insisting each new module_param sysfs entry is unique,
handle the case where it already exists (for builtin modules).

The current code assumes that all identical prefixes are together in
the section: true for normal uses, but not necessarily so if someone
overrides MODULE_PARAM_PREFIX.  More importantly, it's not true with
the new "core_param()" code which uses "kernel" as a prefix.

This simplifies the caller for the builtin case, at a slight loss of
efficiency (we do the lookup every time to see if the directory
exists).
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
      9b473de8
    • Rusty Russell's avatar
      module: check kernel param length at compile time, not runtime · 730b69d2
      Rusty Russell authored 
      The kparam code tries to handle over-length parameter prefixes at
runtime.  Not only would I bet this has never been tested, it's not
clear that truncating names is a good idea either.

So let's check at compile time.  We need to move the #define to
moduleparam.h to do this, though.
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      730b69d2
    • Andi Kleen's avatar
      Remove stop_machine during module load v2 · d72b3751
      Andi Kleen authored 
      Remove stop_machine during module load v2

module loading currently does a stop_machine on each module load to insert
the module into the global module lists.  Especially on larger systems this
can be quite expensive.

It does that to handle concurrent lock lessmodule list readers
like kallsyms.

I don't think stop_machine() is actually needed to insert something
into a list though. There are no concurrent writers because the
module mutex is taken. And the RCU list functions know how to insert
a node into a list with the right memory ordering so that concurrent
readers don't go off into the wood.

So remove the stop_machine for the module list insert and just
do a list_add_rcu() instead.

Module removal will still do a stop_machine of course, it needs
that for other reasons.

v2: Revised readers based on Paul's comments. All readers that only
    rely on disabled preemption need to be changed to list_for_each_rcu().
    Done that. The others are ok because they have the modules mutex.
    Also added a possible missing preempt disable for print_modules().

[cc Paul McKenney for review. It's not RCU, but quite similar.]
Acked-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      d72b3751
    • Rusty Russell's avatar
      module: simplify load_module. · 5e458cc0
      Rusty Russell authored 
      Linus' recent catch of stack overflow in load_module lead me to look
at the code.  A couple of helpers to get a section address and get
objects from a section can help clean things up a little.

(And in case you're wondering, the stack size also dropped from 328 to
284 bytes).
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      5e458cc0
    • Paul Mundt's avatar
      binfmt_elf_fdpic: Update for cputime changes. · 2515ddc6
      Paul Mundt authored 
      Commit f06febc9 ("timers: fix itimer/
many thread hang") introduced a new task_cputime interface and
subsequently only converted binfmt_elf over to it.  This results in the
build for binfmt_elf_fdpic blowing up given that p->signal->{u,s}time
have disappeared from underneath us.

Apply the same trivial fix from binfmt_elf to binfmt_elf_fdpic.
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2515ddc6
  3. 20 Oct, 2008 34 commits