The <linux/module.h> pretty much brings in the kitchen sink along
with it, so it should be avoided wherever reasonably possible in
terms of being included from other commonly used <linux/something.h>
files, as it results in a measureable increase on compile times.

The worst culprit was probably device.h since it is used everywhere.
This file also had an implicit dependency/usage of mutex.h which was
masked by module.h, and is also fixed here at the same time.

There are over a dozen other headers that simply declare the
struct instead of pulling in the whole file, so follow their lead
and simply make it a few more.

Most of the implicit dependencies on module.h being present by
these headers pulling it in have been now weeded out, so we can
finally make this change with hopefully minimal breakage.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NDavid Sharp <dhsharp@google.com>
LKML-Reference: <1291421609-14665-7-git-send-email-dhsharp@google.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The commit:

 9f987b3141f086de27832514aad9f50a53f754
 tracing: Include module.h in define_trace.h

only solved half the problem. If the trace/events/module.h header is
included at the time of define_trace.h (or in ftrace.h within it),
the module.h TRACE_SYSTEM will override the current TRACE_SYSTEM
macro.

Since define_trace.h is included when CREATE_TRACE_POINTS is set,
and the first thing it does is to #undef CREATE_TRACE_POINTS,
by placing the module.h TRACE_SYSTEM inside a
 #ifdef CREATE_TRACE_POINTS
we can prevent it from overriding the TRACE_SYSTEM that is
being processed, and still process the module.h tracepoints
when the module code defines CREATE_TRACE_POINTS and includes
the trace/events/module.h header.

As with commit 9f987b3141, this is only an issue if module.h
is not included before the trace/events/<event>.h file is
included, which (luckily) has not happened yet.
Reported-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

If modules are configured in the build but unloading of modules is not,
then the refcnt is not defined. Place the get/put module tracepoints
under CONFIG_MODULE_UNLOAD since it references this field in the module
structure.

As a side-effect, this patch also reduces the code when MODULE_UNLOAD
is not set, because these unused tracepoints are not created.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Remove the @refcnt argument, because it has side-effects, and arguments with
side-effects are not skipped by the jump over disabled instrumentation and are
executed even when the tracepoint is disabled.

This was also causing a GPF as found by Randy Dunlap:

Subject: 2.6.33 GP fault only when built with tracing
LKML-Reference: <4BA2B69D.3000309@oracle.com>

Note, the current 2.6.34-rc has a fix for the actual cause of the GPF,
but this fixes one of its triggers.
Tested-by: NRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BA97FA7.6040406@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Use DECLARE_EVENT_CLASS to remove duplicate code:

   text    data     bss     dec     hex filename
  29854    1980     128   31962    7cda kernel/module.o.old
  28750    1980     128   30858    788a kernel/module.o

Two events are converted:

  module_refcnt: module_get, module_put

No change in functionality.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B0E283B.3010508@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add trace points to trace module_load, module_free, module_get,
module_put and module_request, and use trace_event facility to
get the trace output.

Here's the sample output:

     TASK-PID    CPU#    TIMESTAMP  FUNCTION
        | |       |          |         |
    <...>-42    [000]     1.758380: module_request: fb0 wait=1 call_site=fb_open
    ...
    <...>-60    [000]     3.269403: module_load: scsi_wait_scan
    <...>-60    [000]     3.269432: module_put: scsi_wait_scan call_site=sys_init_module refcnt=0
    <...>-61    [001]     3.273168: module_free: scsi_wait_scan
    ...
    <...>-1021  [000]    13.836081: module_load: sunrpc
    <...>-1021  [000]    13.840589: module_put: sunrpc call_site=sys_init_module refcnt=-1
    <...>-1027  [000]    13.848098: module_get: sunrpc call_site=try_module_get refcnt=0
    <...>-1027  [000]    13.848308: module_get: sunrpc call_site=get_filesystem refcnt=1
    <...>-1027  [000]    13.848692: module_put: sunrpc call_site=put_filesystem refcnt=0
    ...
 modprobe-2587  [001]  1088.437213: module_load: trace_events_sample F
 modprobe-2587  [001]  1088.437786: module_put: trace_events_sample call_site=sys_init_module refcnt=0

Note:

- the taints flag can be 'F', 'C' and/or 'P' if mod->taints != 0

- the module refcnt is percpu, so it can be negative in a
  specific cpu
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <4A891B3C.5030608@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>