Message-ID: <20070715234703.GM22428@Krystal>
Date:	Sun, 15 Jul 2007 19:47:03 -0400
From:	Mathieu Desnoyers <compudj@...stal.dyndns.org>
To:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Cc:	Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH] Linux Kernel Markers - Architecture Independent Code - kerneldoc for implementation

Please drop: it came from the wrong email. I will resend.

* Mathieu Desnoyers (compudj@...stal.dyndns.org) wrote:
> Linux Kernel Markers - Architecture Independent Code - kerneldoc for implementation
> 
> Add kerneldoc to Linux Kernel Markers API.
> It applies after:
> "linux-kernel-markers-architecture-independent-code-remove-ifdef-kernel.patch"
> 
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
> CC: hch@...radead.org
> ---
>  include/linux/marker.h |   37 +++++++++++++---
>  kernel/marker.c        |  113 ++++++++++++++++++++++++++++++++++---------------
>  2 files changed, 112 insertions(+), 38 deletions(-)
> 
> Index: linux-2.6-lttng/include/linux/marker.h
> ===================================================================
> --- linux-2.6-lttng.orig/include/linux/marker.h	2007-07-15 19:19:10.000000000 -0400
> +++ linux-2.6-lttng/include/linux/marker.h	2007-07-15 19:20:47.000000000 -0400
> @@ -18,6 +18,15 @@
>  struct module;
>  struct __mark_marker;
>  
> +/**
> + * marker_probe_func - Type of a marker probe function
> + * @mdata: pointer of type struct __mark_marker
> + * @fmt: format string
> + * @...: variable argument list
> + *
> + * Type of marker probe functions. They receive the mdata and need to parse the
> + * format string to recover the variable argument list.
> + */
>  typedef void marker_probe_func(const struct __mark_marker *mdata,
>  	const char *fmt, ...);
>  
> @@ -86,18 +95,36 @@ extern void module_marker_update(struct 
>  static inline void module_marker_update(struct module *mod) { }
>  #endif /* CONFIG_MARKERS */
>  
> -/* Marker with default behavior */
> +/**
> + * trace_mark - Marker using code patching
> + * @name: marker name, not quoted.
> + * @format: format string
> + * @args...: variable argument list
> + *
> + * Places a marker using optimized code patching technique (immediate_if ())
> + * to be enabled.
> + */
>  #define trace_mark(name, format, args...) \
>  	__trace_mark(0, name, format, ## args)
> -/*
> - * Map to the generic marker. Should be used for markers in __init and __exit
> - * functions and in lockdep code.
> +
> +/**
> + * _trace_mark - Marker using variable read
> + * @name: marker name, not quoted.
> + * @format: format string
> + * @args...: variable argument list
> + *
> + * Places a marker using a standard memory read (_immediate_if ()) to be
> + * enabled. Should be used for markers in __init and __exit functions and in
> + * lockdep code.
>   */
>  #define _trace_mark(name, format, args...) \
>  	__trace_mark(1, name, format, ## args)
>  
>  #define MARK_MAX_FORMAT_LEN	1024
> -/* Pass this as a format string for a marker with no argument */
> +
> +/**
> + * MARK_NOARGS - Format string for a marker with no argument.
> + */
>  #define MARK_NOARGS " "
>  
>  /* To be used for string format validity checking with gcc */
> Index: linux-2.6-lttng/kernel/marker.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/marker.c	2007-07-15 19:20:53.000000000 -0400
> +++ linux-2.6-lttng/kernel/marker.c	2007-07-15 19:26:53.000000000 -0400
> @@ -62,7 +62,12 @@ struct marker_entry {
>  
>  static struct hlist_head marker_table[MARKER_TABLE_SIZE];
>  
> -/*
> +/**
> + * __mark_empty_function - Empty probe callback
> + * @mdata: pointer of type const struct __mark_marker
> + * @fmt: format string
> + * @...: variable argument list
> + *
>   * Empty callback provided as a probe to the markers. By providing this to a
>   * disabled marker, we makes sure the  execution flow is always valid even
>   * though the function pointer change and the marker enabling are two distinct
> @@ -199,7 +204,9 @@ static int _marker_set_format(struct mar
>  	return 0;
>  }
>  
> -/* Sets the probe callback corresponding to one marker. */
> +/*
> + * Sets the probe callback corresponding to one marker.
> + */
>  static int _set_marker(struct marker_entry **entry,
>  			struct __mark_marker *elem)
>  {
> @@ -320,11 +327,13 @@ static inline void __marker_update_probe
>  }
>  
>  #ifdef CONFIG_MODULES
> -/*
> +/**
> + * module_marker_update - Update module's markers
> + * @mod: pointer of type struct module identifying the target module
> + *
>   * Setup the marker according to the data present in the marker hash table
> - * upon module load. If an error occur during the set probe range,
> - * refuse to load the module. Must be called with module_mutex held.
> - * Since the probe_module parameter is NULL, it is safe for refcount to be NULL.
> + * upon module load. Must be called with module_mutex held.  Since the
> + * probe_module parameter is NULL, it is safe for refcount to be NULL.
>   */
>  void module_marker_update(struct module *mod)
>  {
> @@ -334,7 +343,8 @@ void module_marker_update(struct module 
>  }
>  
>  /*
> - * Update the system wide probes, with modules. */
> + * Update the system wide probes, with modules.
> + */
>  static inline void _marker_update_probes(struct module *probe_module)
>  {
>  	mutex_lock(&module_mutex);
> @@ -342,16 +352,24 @@ static inline void _marker_update_probes
>  	mutex_unlock(&module_mutex);
>  }
>  #else
> -/* Update the system wide probes, without modules. */
> +/*
> + * Update the system wide probes, without modules.
> + */
>  static inline void _marker_update_probes(struct module *probe_module)
>  {
>  	__marker_update_probes(probe_module);
>  }
>  #endif
>  
> -/*
> - * Register a probe : set the callback for each marker.
> - * Markers must be disarmed to be registered.
> +/**
> + * marker_probe_register -  Connect a probe to a marker
> + * @name: marker name
> + * @format: format string
> + * @probe: probe handler
> + * @pdata: probe private data
> + *
> + * pdata must be a valid allocated memory address, or NULL.
> + * Returns 0 if ok, error value on error.
>   */
>  int marker_probe_register(const char *name, const char *format,
>  			marker_probe_func *probe, void *pdata)
> @@ -379,10 +397,11 @@ end:
>  }
>  EXPORT_SYMBOL_GPL(marker_probe_register);
>  
> -/*
> - * Unregister a probe : unset the callback for each marker.
> - * returns the pdata if ok.
> - * else, returns a ERR_PTR().
> +/**
> + * marker_probe_unregister -  Disconnect a probe from a marker
> + * @name: marker name
> + *
> + * Returns the pdata given to marker_probe_register, or an ERR_PTR().
>   */
>  void *marker_probe_unregister(const char *name)
>  {
> @@ -408,11 +427,12 @@ end:
>  }
>  EXPORT_SYMBOL_GPL(marker_probe_unregister);
>  
> -/*
> - * Unregister a probe by pdata : unset the callback for each marker.
> - * Markers must be disarmed to be unregistered.
> - * returns the pdata if ok.
> - * else, returns a ERR_PTR().
> +/**
> + * marker_probe_unregister -  Disconnect a probe from a marker
> + * @pdata: probe private data
> + *
> + * Unregister a marker by providing the registered pdata.
> + * Returns the pdata given to marker_probe_register, or an ERR_PTR().
>   */
>  void *marker_probe_unregister_pdata(void *pdata)
>  {
> @@ -450,9 +470,13 @@ end:
>  }
>  EXPORT_SYMBOL_GPL(marker_probe_unregister_pdata);
>  
> -/*
> - * Arm the probe : arm the immediate values.
> - * A probe must have been previously registered.
> +/**
> + * marker_arm - Arm a marker
> + * @name: marker name
> + *
> + * Activate a marker. It keeps a reference count of the number of
> + * arming/disarming done.
> + * Returns 0 if ok, error value on error.
>   */
>  int marker_arm(const char *name)
>  {
> @@ -477,9 +501,13 @@ end:
>  }
>  EXPORT_SYMBOL_GPL(marker_arm);
>  
> -/*
> - * Disarm the probe : disarm the immediate and set the empty callback for each
> - * marker.
> +/**
> + * marker_disarm - Disarm a marker
> + * @name: marker name
> + *
> + * Disarm a marker. It keeps a reference count of the number of arming/disarming
> + * done.
> + * Returns 0 if ok, error value on error.
>   */
>  int marker_disarm(const char *name)
>  {
> @@ -510,6 +538,15 @@ end:
>  }
>  EXPORT_SYMBOL_GPL(marker_disarm);
>  
> +/**
> + * marker_get_pdata - Get a marker's probe private data
> + * @name: marker name
> + *
> + * Returns the pdata pointer, or an ERR_PTR.
> + * The pdata pointer should _only_ be dereferenced if the caller is the owner of
> + * the data, or its content could vanish. This is mostly used to confirm that a
> + * caller is the owner of a registered probe.
> + */
>  void *marker_get_pdata(const char *name)
>  {
>  	struct hlist_head *head;
> @@ -530,7 +567,6 @@ void *marker_get_pdata(const char *name)
>  }
>  EXPORT_SYMBOL_GPL(marker_get_pdata);
>  
> -
>  /*
>   * No markers are added to the core marker section, no lock needed.
>   * Must be called with modules mutex held for modules markers.
> @@ -609,11 +645,12 @@ static inline int marker_get_next_module
>  }
>  #endif
>  
> -/*
> - * Only need to increment the module use count.
> - * We allow modification of markers beneath us, since we only want to output
> - * their information.
> - * Returns NULL when it reaches the last marker.
> +/**
> + * marker_get_next - Get next marker of an iteration
> + * @iter: previous marker
> + *
> + * Get the next marker found in the kernel. It should get its previous marker
> + * from either marker_get_first() or marker_get_next().
>   */
>  struct __mark_marker *marker_get_next(struct __mark_marker *cur)
>  {
> @@ -635,13 +672,23 @@ end:
>  }
>  EXPORT_SYMBOL_GPL(marker_get_next);
>  
> +/**
> + * marker_get_first - Get first marker to start iteration
> + *
> + * Get the first marker found in the kernel. It should have a matching
> + * marker_release.
> + */
>  struct __mark_marker *marker_get_first(void)
>  {
>  	return marker_get_next(NULL);
>  }
>  EXPORT_SYMBOL_GPL(marker_get_first);
>  
> -/*
> +/**
> + * marker_release - Release the marker iterator
> + * @iter: previous marker
> + *
> + * Release the ressources held to insure iterator validity.
>   * FIXME: suboptimal
>   * Gets the markers until the end, so no module refcount is held when the
>   * function ends.
> 
> -- 
> Mathieu Desnoyers
> Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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