summaryrefslogtreecommitdiffstats
path: root/kernel/marker.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/marker.c')
-rw-r--r--kernel/marker.c930
1 files changed, 0 insertions, 930 deletions
diff --git a/kernel/marker.c b/kernel/marker.c
deleted file mode 100644
index ea54f264786..00000000000
--- a/kernel/marker.c
+++ /dev/null
@@ -1,930 +0,0 @@
-/*
- * Copyright (C) 2007 Mathieu Desnoyers
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- */
-#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/types.h>
-#include <linux/jhash.h>
-#include <linux/list.h>
-#include <linux/rcupdate.h>
-#include <linux/marker.h>
-#include <linux/err.h>
-#include <linux/slab.h>
-
-extern struct marker __start___markers[];
-extern struct marker __stop___markers[];
-
-/* Set to 1 to enable marker debug output */
-static const int marker_debug;
-
-/*
- * markers_mutex nests inside module_mutex. Markers mutex protects the builtin
- * and module markers and the hash table.
- */
-static DEFINE_MUTEX(markers_mutex);
-
-/*
- * Marker hash table, containing the active markers.
- * Protected by module_mutex.
- */
-#define MARKER_HASH_BITS 6
-#define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
-static struct hlist_head marker_table[MARKER_TABLE_SIZE];
-
-/*
- * Note about RCU :
- * It is used to make sure every handler has finished using its private data
- * between two consecutive operation (add or remove) on a given marker. It is
- * also used to delay the free of multiple probes array until a quiescent state
- * is reached.
- * marker entries modifications are protected by the markers_mutex.
- */
-struct marker_entry {
- struct hlist_node hlist;
- char *format;
- /* Probe wrapper */
- void (*call)(const struct marker *mdata, void *call_private, ...);
- struct marker_probe_closure single;
- struct marker_probe_closure *multi;
- int refcount; /* Number of times armed. 0 if disarmed. */
- struct rcu_head rcu;
- void *oldptr;
- int rcu_pending;
- unsigned char ptype:1;
- unsigned char format_allocated:1;
- char name[0]; /* Contains name'\0'format'\0' */
-};
-
-/**
- * __mark_empty_function - Empty probe callback
- * @probe_private: probe private data
- * @call_private: call site private data
- * @fmt: format string
- * @...: variable argument list
- *
- * Empty callback provided as a probe to the markers. By providing this to a
- * disabled marker, we make sure the execution flow is always valid even
- * though the function pointer change and the marker enabling are two distinct
- * operations that modifies the execution flow of preemptible code.
- */
-notrace void __mark_empty_function(void *probe_private, void *call_private,
- const char *fmt, va_list *args)
-{
-}
-EXPORT_SYMBOL_GPL(__mark_empty_function);
-
-/*
- * marker_probe_cb Callback that prepares the variable argument list for probes.
- * @mdata: pointer of type struct marker
- * @call_private: caller site private data
- * @...: Variable argument list.
- *
- * Since we do not use "typical" pointer based RCU in the 1 argument case, we
- * need to put a full smp_rmb() in this branch. This is why we do not use
- * rcu_dereference() for the pointer read.
- */
-notrace void marker_probe_cb(const struct marker *mdata,
- void *call_private, ...)
-{
- va_list args;
- char ptype;
-
- /*
- * rcu_read_lock_sched does two things : disabling preemption to make
- * sure the teardown of the callbacks can be done correctly when they
- * are in modules and they insure RCU read coherency.
- */
- rcu_read_lock_sched_notrace();
- ptype = mdata->ptype;
- if (likely(!ptype)) {
- marker_probe_func *func;
- /* Must read the ptype before ptr. They are not data dependant,
- * so we put an explicit smp_rmb() here. */
- smp_rmb();
- func = mdata->single.func;
- /* Must read the ptr before private data. They are not data
- * dependant, so we put an explicit smp_rmb() here. */
- smp_rmb();
- va_start(args, call_private);
- func(mdata->single.probe_private, call_private, mdata->format,
- &args);
- va_end(args);
- } else {
- struct marker_probe_closure *multi;
- int i;
- /*
- * Read mdata->ptype before mdata->multi.
- */
- smp_rmb();
- multi = mdata->multi;
- /*
- * multi points to an array, therefore accessing the array
- * depends on reading multi. However, even in this case,
- * we must insure that the pointer is read _before_ the array
- * data. Same as rcu_dereference, but we need a full smp_rmb()
- * in the fast path, so put the explicit barrier here.
- */
- smp_read_barrier_depends();
- for (i = 0; multi[i].func; i++) {
- va_start(args, call_private);
- multi[i].func(multi[i].probe_private, call_private,
- mdata->format, &args);
- va_end(args);
- }
- }
- rcu_read_unlock_sched_notrace();
-}
-EXPORT_SYMBOL_GPL(marker_probe_cb);
-
-/*
- * marker_probe_cb Callback that does not prepare the variable argument list.
- * @mdata: pointer of type struct marker
- * @call_private: caller site private data
- * @...: Variable argument list.
- *
- * Should be connected to markers "MARK_NOARGS".
- */
-static notrace void marker_probe_cb_noarg(const struct marker *mdata,
- void *call_private, ...)
-{
- va_list args; /* not initialized */
- char ptype;
-
- rcu_read_lock_sched_notrace();
- ptype = mdata->ptype;
- if (likely(!ptype)) {
- marker_probe_func *func;
- /* Must read the ptype before ptr. They are not data dependant,
- * so we put an explicit smp_rmb() here. */
- smp_rmb();
- func = mdata->single.func;
- /* Must read the ptr before private data. They are not data
- * dependant, so we put an explicit smp_rmb() here. */
- smp_rmb();
- func(mdata->single.probe_private, call_private, mdata->format,
- &args);
- } else {
- struct marker_probe_closure *multi;
- int i;
- /*
- * Read mdata->ptype before mdata->multi.
- */
- smp_rmb();
- multi = mdata->multi;
- /*
- * multi points to an array, therefore accessing the array
- * depends on reading multi. However, even in this case,
- * we must insure that the pointer is read _before_ the array
- * data. Same as rcu_dereference, but we need a full smp_rmb()
- * in the fast path, so put the explicit barrier here.
- */
- smp_read_barrier_depends();
- for (i = 0; multi[i].func; i++)
- multi[i].func(multi[i].probe_private, call_private,
- mdata->format, &args);
- }
- rcu_read_unlock_sched_notrace();
-}
-
-static void free_old_closure(struct rcu_head *head)
-{
- struct marker_entry *entry = container_of(head,
- struct marker_entry, rcu);
- kfree(entry->oldptr);
- /* Make sure we free the data before setting the pending flag to 0 */
- smp_wmb();
- entry->rcu_pending = 0;
-}
-
-static void debug_print_probes(struct marker_entry *entry)
-{
- int i;
-
- if (!marker_debug)
- return;
-
- if (!entry->ptype) {
- printk(KERN_DEBUG "Single probe : %p %p\n",
- entry->single.func,
- entry->single.probe_private);
- } else {
- for (i = 0; entry->multi[i].func; i++)
- printk(KERN_DEBUG "Multi probe %d : %p %p\n", i,
- entry->multi[i].func,
- entry->multi[i].probe_private);
- }
-}
-
-static struct marker_probe_closure *
-marker_entry_add_probe(struct marker_entry *entry,
- marker_probe_func *probe, void *probe_private)
-{
- int nr_probes = 0;
- struct marker_probe_closure *old, *new;
-
- WARN_ON(!probe);
-
- debug_print_probes(entry);
- old = entry->multi;
- if (!entry->ptype) {
- if (entry->single.func == probe &&
- entry->single.probe_private == probe_private)
- return ERR_PTR(-EBUSY);
- if (entry->single.func == __mark_empty_function) {
- /* 0 -> 1 probes */
- entry->single.func = probe;
- entry->single.probe_private = probe_private;
- entry->refcount = 1;
- entry->ptype = 0;
- debug_print_probes(entry);
- return NULL;
- } else {
- /* 1 -> 2 probes */
- nr_probes = 1;
- old = NULL;
- }
- } else {
- /* (N -> N+1), (N != 0, 1) probes */
- for (nr_probes = 0; old[nr_probes].func; nr_probes++)
- if (old[nr_probes].func == probe
- && old[nr_probes].probe_private
- == probe_private)
- return ERR_PTR(-EBUSY);
- }
- /* + 2 : one for new probe, one for NULL func */
- new = kzalloc((nr_probes + 2) * sizeof(struct marker_probe_closure),
- GFP_KERNEL);
- if (new == NULL)
- return ERR_PTR(-ENOMEM);
- if (!old)
- new[0] = entry->single;
- else
- memcpy(new, old,
- nr_probes * sizeof(struct marker_probe_closure));
- new[nr_probes].func = probe;
- new[nr_probes].probe_private = probe_private;
- entry->refcount = nr_probes + 1;
- entry->multi = new;
- entry->ptype = 1;
- debug_print_probes(entry);
- return old;
-}
-
-static struct marker_probe_closure *
-marker_entry_remove_probe(struct marker_entry *entry,
- marker_probe_func *probe, void *probe_private)
-{
- int nr_probes = 0, nr_del = 0, i;
- struct marker_probe_closure *old, *new;
-
- old = entry->multi;
-
- debug_print_probes(entry);
- if (!entry->ptype) {
- /* 0 -> N is an error */
- WARN_ON(entry->single.func == __mark_empty_function);
- /* 1 -> 0 probes */
- WARN_ON(probe && entry->single.func != probe);
- WARN_ON(entry->single.probe_private != probe_private);
- entry->single.func = __mark_empty_function;
- entry->refcount = 0;
- entry->ptype = 0;
- debug_print_probes(entry);
- return NULL;
- } else {
- /* (N -> M), (N > 1, M >= 0) probes */
- for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
- if ((!probe || old[nr_probes].func == probe)
- && old[nr_probes].probe_private
- == probe_private)
- nr_del++;
- }
- }
-
- if (nr_probes - nr_del == 0) {
- /* N -> 0, (N > 1) */
- entry->single.func = __mark_empty_function;
- entry->refcount = 0;
- entry->ptype = 0;
- } else if (nr_probes - nr_del == 1) {
- /* N -> 1, (N > 1) */
- for (i = 0; old[i].func; i++)
- if ((probe && old[i].func != probe) ||
- old[i].probe_private != probe_private)
- entry->single = old[i];
- entry->refcount = 1;
- entry->ptype = 0;
- } else {
- int j = 0;
- /* N -> M, (N > 1, M > 1) */
- /* + 1 for NULL */
- new = kzalloc((nr_probes - nr_del + 1)
- * sizeof(struct marker_probe_closure), GFP_KERNEL);
- if (new == NULL)
- return ERR_PTR(-ENOMEM);
- for (i = 0; old[i].func; i++)
- if ((probe && old[i].func != probe) ||
- old[i].probe_private != probe_private)
- new[j++] = old[i];
- entry->refcount = nr_probes - nr_del;
- entry->ptype = 1;
- entry->multi = new;
- }
- debug_print_probes(entry);
- return old;
-}
-
-/*
- * Get marker if the marker is present in the marker hash table.
- * Must be called with markers_mutex held.
- * Returns NULL if not present.
- */
-static struct marker_entry *get_marker(const char *name)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct marker_entry *e;
- u32 hash = jhash(name, strlen(name), 0);
-
- head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
- hlist_for_each_entry(e, node, head, hlist) {
- if (!strcmp(name, e->name))
- return e;
- }
- return NULL;
-}
-
-/*
- * Add the marker to the marker hash table. Must be called with markers_mutex
- * held.
- */
-static struct marker_entry *add_marker(const char *name, const char *format)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct marker_entry *e;
- size_t name_len = strlen(name) + 1;
- size_t format_len = 0;
- u32 hash = jhash(name, name_len-1, 0);
-
- if (format)
- format_len = strlen(format) + 1;
- head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
- hlist_for_each_entry(e, node, head, hlist) {
- if (!strcmp(name, e->name)) {
- printk(KERN_NOTICE
- "Marker %s busy\n", name);
- return ERR_PTR(-EBUSY); /* Already there */
- }
- }
- /*
- * Using kmalloc here to allocate a variable length element. Could
- * cause some memory fragmentation if overused.
- */
- e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
- GFP_KERNEL);
- if (!e)
- return ERR_PTR(-ENOMEM);
- memcpy(&e->name[0], name, name_len);
- if (format) {
- e->format = &e->name[name_len];
- memcpy(e->format, format, format_len);
- if (strcmp(e->format, MARK_NOARGS) == 0)
- e->call = marker_probe_cb_noarg;
- else
- e->call = marker_probe_cb;
- trace_mark(core_marker_format, "name %s format %s",
- e->name, e->format);
- } else {
- e->format = NULL;
- e->call = marker_probe_cb;
- }
- e->single.func = __mark_empty_function;
- e->single.probe_private = NULL;
- e->multi = NULL;
- e->ptype = 0;
- e->format_allocated = 0;
- e->refcount = 0;
- e->rcu_pending = 0;
- hlist_add_head(&e->hlist, head);
- return e;
-}
-
-/*
- * Remove the marker from the marker hash table. Must be called with mutex_lock
- * held.
- */
-static int remove_marker(const char *name)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct marker_entry *e;
- int found = 0;
- size_t len = strlen(name) + 1;
- u32 hash = jhash(name, len-1, 0);
-
- head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
- hlist_for_each_entry(e, node, head, hlist) {
- if (!strcmp(name, e->name)) {
- found = 1;
- break;
- }
- }
- if (!found)
- return -ENOENT;
- if (e->single.func != __mark_empty_function)
- return -EBUSY;
- hlist_del(&e->hlist);
- if (e->format_allocated)
- kfree(e->format);
- /* Make sure the call_rcu has been executed */
- if (e->rcu_pending)
- rcu_barrier_sched();
- kfree(e);
- return 0;
-}
-
-/*
- * Set the mark_entry format to the format found in the element.
- */
-static int marker_set_format(struct marker_entry *entry, const char *format)
-{
- entry->format = kstrdup(format, GFP_KERNEL);
- if (!entry->format)
- return -ENOMEM;
- entry->format_allocated = 1;
-
- trace_mark(core_marker_format, "name %s format %s",
- entry->name, entry->format);
- return 0;
-}
-
-/*
- * Sets the probe callback corresponding to one marker.
- */
-static int set_marker(struct marker_entry *entry, struct marker *elem,
- int active)
-{
- int ret = 0;
- WARN_ON(strcmp(entry->name, elem->name) != 0);
-
- if (entry->format) {
- if (strcmp(entry->format, elem->format) != 0) {
- printk(KERN_NOTICE
- "Format mismatch for probe %s "
- "(%s), marker (%s)\n",
- entry->name,
- entry->format,
- elem->format);
- return -EPERM;
- }
- } else {
- ret = marker_set_format(entry, elem->format);
- if (ret)
- return ret;
- }
-
- /*
- * probe_cb setup (statically known) is done here. It is
- * asynchronous with the rest of execution, therefore we only
- * pass from a "safe" callback (with argument) to an "unsafe"
- * callback (does not set arguments).
- */
- elem->call = entry->call;
- /*
- * Sanity check :
- * We only update the single probe private data when the ptr is
- * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
- */
- WARN_ON(elem->single.func != __mark_empty_function
- && elem->single.probe_private != entry->single.probe_private
- && !elem->ptype);
- elem->single.probe_private = entry->single.probe_private;
- /*
- * Make sure the private data is valid when we update the
- * single probe ptr.
- */
- smp_wmb();
- elem->single.func = entry->single.func;
- /*
- * We also make sure that the new probe callbacks array is consistent
- * before setting a pointer to it.
- */
- rcu_assign_pointer(elem->multi, entry->multi);
- /*
- * Update the function or multi probe array pointer before setting the
- * ptype.
- */
- smp_wmb();
- elem->ptype = entry->ptype;
-
- if (elem->tp_name && (active ^ elem->state)) {
- WARN_ON(!elem->tp_cb);
- /*
- * It is ok to directly call the probe registration because type
- * checking has been done in the __trace_mark_tp() macro.
- */
-
- if (active) {
- /*
- * try_module_get should always succeed because we hold
- * lock_module() to get the tp_cb address.
- */
- ret = try_module_get(__module_text_address(
- (unsigned long)elem->tp_cb));
- BUG_ON(!ret);
- ret = tracepoint_probe_register_noupdate(
- elem->tp_name,
- elem->tp_cb);
- } else {
- ret = tracepoint_probe_unregister_noupdate(
- elem->tp_name,
- elem->tp_cb);
- /*
- * tracepoint_probe_update_all() must be called
- * before the module containing tp_cb is unloaded.
- */
- module_put(__module_text_address(
- (unsigned long)elem->tp_cb));
- }
- }
- elem->state = active;
-
- return ret;
-}
-
-/*
- * Disable a marker and its probe callback.
- * Note: only waiting an RCU period after setting elem->call to the empty
- * function insures that the original callback is not used anymore. This insured
- * by rcu_read_lock_sched around the call site.
- */
-static void disable_marker(struct marker *elem)
-{
- int ret;
-
- /* leave "call" as is. It is known statically. */
- if (elem->tp_name && elem->state) {
- WARN_ON(!elem->tp_cb);
- /*
- * It is ok to directly call the probe registration because type
- * checking has been done in the __trace_mark_tp() macro.
- */
- ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
- elem->tp_cb);
- WARN_ON(ret);
- /*
- * tracepoint_probe_update_all() must be called
- * before the module containing tp_cb is unloaded.
- */
- module_put(__module_text_address((unsigned long)elem->tp_cb));
- }
- elem->state = 0;
- elem->single.func = __mark_empty_function;
- /* Update the function before setting the ptype */
- smp_wmb();
- elem->ptype = 0; /* single probe */
- /*
- * Leave the private data and id there, because removal is racy and
- * should be done only after an RCU period. These are never used until
- * the next initialization anyway.
- */
-}
-
-/**
- * marker_update_probe_range - Update a probe range
- * @begin: beginning of the range
- * @end: end of the range
- *
- * Updates the probe callback corresponding to a range of markers.
- */
-void marker_update_probe_range(struct marker *begin,
- struct marker *end)
-{
- struct marker *iter;
- struct marker_entry *mark_entry;
-
- mutex_lock(&markers_mutex);
- for (iter = begin; iter < end; iter++) {
- mark_entry = get_marker(iter->name);
- if (mark_entry) {
- set_marker(mark_entry, iter, !!mark_entry->refcount);
- /*
- * ignore error, continue
- */
- } else {
- disable_marker(iter);
- }
- }
- mutex_unlock(&markers_mutex);
-}
-
-/*
- * Update probes, removing the faulty probes.
- *
- * Internal callback only changed before the first probe is connected to it.
- * Single probe private data can only be changed on 0 -> 1 and 2 -> 1
- * transitions. All other transitions will leave the old private data valid.
- * This makes the non-atomicity of the callback/private data updates valid.
- *
- * "special case" updates :
- * 0 -> 1 callback
- * 1 -> 0 callback
- * 1 -> 2 callbacks
- * 2 -> 1 callbacks
- * Other updates all behave the same, just like the 2 -> 3 or 3 -> 2 updates.
- * Site effect : marker_set_format may delete the marker entry (creating a
- * replacement).
- */
-static void marker_update_probes(void)
-{
- /* Core kernel markers */
- marker_update_probe_range(__start___markers, __stop___markers);
- /* Markers in modules. */
- module_update_markers();
- tracepoint_probe_update_all();
-}
-
-/**
- * marker_probe_register - Connect a probe to a marker
- * @name: marker name
- * @format: format string
- * @probe: probe handler
- * @probe_private: probe private data
- *
- * private data must be a valid allocated memory address, or NULL.
- * Returns 0 if ok, error value on error.
- * The probe address must at least be aligned on the architecture pointer size.
- */
-int marker_probe_register(const char *name, const char *format,
- marker_probe_func *probe, void *probe_private)
-{
- struct marker_entry *entry;
- int ret = 0;
- struct marker_probe_closure *old;
-
- mutex_lock(&markers_mutex);
- entry = get_marker(name);
- if (!entry) {
- entry = add_marker(name, format);
- if (IS_ERR(entry))
- ret = PTR_ERR(entry);
- } else if (format) {
- if (!entry->format)
- ret = marker_set_format(entry, format);
- else if (strcmp(entry->format, format))
- ret = -EPERM;
- }
- if (ret)
- goto end;
-
- /*
- * If we detect that a call_rcu is pending for this marker,
- * make sure it's executed now.
- */
- if (entry->rcu_pending)
- rcu_barrier_sched();
- old = marker_entry_add_probe(entry, probe, probe_private);
- if (IS_ERR(old)) {
- ret = PTR_ERR(old);
- goto end;
- }
- mutex_unlock(&markers_mutex);
- marker_update_probes();
- mutex_lock(&markers_mutex);
- entry = get_marker(name);
- if (!entry)
- goto end;
- if (entry->rcu_pending)
- rcu_barrier_sched();
- entry->oldptr = old;
- entry->rcu_pending = 1;
- /* write rcu_pending before calling the RCU callback */
- smp_wmb();
- call_rcu_sched(&entry->rcu, free_old_closure);
-end:
- mutex_unlock(&markers_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_register);
-
-/**
- * marker_probe_unregister - Disconnect a probe from a marker
- * @name: marker name
- * @probe: probe function pointer
- * @probe_private: probe private data
- *
- * Returns the private data given to marker_probe_register, or an ERR_PTR().
- * We do not need to call a synchronize_sched to make sure the probes have
- * finished running before doing a module unload, because the module unload
- * itself uses stop_machine(), which insures that every preempt disabled section
- * have finished.
- */
-int marker_probe_unregister(const char *name,
- marker_probe_func *probe, void *probe_private)
-{
- struct marker_entry *entry;
- struct marker_probe_closure *old;
- int ret = -ENOENT;
-
- mutex_lock(&markers_mutex);
- entry = get_marker(name);
- if (!entry)
- goto end;
- if (entry->rcu_pending)
- rcu_barrier_sched();
- old = marker_entry_remove_probe(entry, probe, probe_private);
- mutex_unlock(&markers_mutex);
- marker_update_probes();
- mutex_lock(&markers_mutex);
- entry = get_marker(name);
- if (!entry)
- goto end;
- if (entry->rcu_pending)
- rcu_barrier_sched();
- entry->oldptr = old;
- entry->rcu_pending = 1;
- /* write rcu_pending before calling the RCU callback */
- smp_wmb();
- call_rcu_sched(&entry->rcu, free_old_closure);
- remove_marker(name); /* Ignore busy error message */
- ret = 0;
-end:
- mutex_unlock(&markers_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_unregister);
-
-static struct marker_entry *
-get_marker_from_private_data(marker_probe_func *probe, void *probe_private)
-{
- struct marker_entry *entry;
- unsigned int i;
- struct hlist_head *head;
- struct hlist_node *node;
-
- for (i = 0; i < MARKER_TABLE_SIZE; i++) {
- head = &marker_table[i];
- hlist_for_each_entry(entry, node, head, hlist) {
- if (!entry->ptype) {
- if (entry->single.func == probe
- && entry->single.probe_private
- == probe_private)
- return entry;
- } else {
- struct marker_probe_closure *closure;
- closure = entry->multi;
- for (i = 0; closure[i].func; i++) {
- if (closure[i].func == probe &&
- closure[i].probe_private
- == probe_private)
- return entry;
- }
- }
- }
- }
- return NULL;
-}
-
-/**
- * marker_probe_unregister_private_data - Disconnect a probe from a marker
- * @probe: probe function
- * @probe_private: probe private data
- *
- * Unregister a probe by providing the registered private data.
- * Only removes the first marker found in hash table.
- * Return 0 on success or error value.
- * We do not need to call a synchronize_sched to make sure the probes have
- * finished running before doing a module unload, because the module unload
- * itself uses stop_machine(), which insures that every preempt disabled section
- * have finished.
- */
-int marker_probe_unregister_private_data(marker_probe_func *probe,
- void *probe_private)
-{
- struct marker_entry *entry;
- int ret = 0;
- struct marker_probe_closure *old;
-
- mutex_lock(&markers_mutex);
- entry = get_marker_from_private_data(probe, probe_private);
- if (!entry) {
- ret = -ENOENT;
- goto end;
- }
- if (entry->rcu_pending)
- rcu_barrier_sched();
- old = marker_entry_remove_probe(entry, NULL, probe_private);
- mutex_unlock(&markers_mutex);
- marker_update_probes();
- mutex_lock(&markers_mutex);
- entry = get_marker_from_private_data(probe, probe_private);
- if (!entry)
- goto end;
- if (entry->rcu_pending)
- rcu_barrier_sched();
- entry->oldptr = old;
- entry->rcu_pending = 1;
- /* write rcu_pending before calling the RCU callback */
- smp_wmb();
- call_rcu_sched(&entry->rcu, free_old_closure);
- remove_marker(entry->name); /* Ignore busy error message */
-end:
- mutex_unlock(&markers_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data);
-
-/**
- * marker_get_private_data - Get a marker's probe private data
- * @name: marker name
- * @probe: probe to match
- * @num: get the nth matching probe's private data
- *
- * Returns the nth private data pointer (starting from 0) matching, or an
- * ERR_PTR.
- * Returns the private data pointer, or an ERR_PTR.
- * The private data 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_private_data(const char *name, marker_probe_func *probe,
- int num)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct marker_entry *e;
- size_t name_len = strlen(name) + 1;
- u32 hash = jhash(name, name_len-1, 0);
- int i;
-
- head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
- hlist_for_each_entry(e, node, head, hlist) {
- if (!strcmp(name, e->name)) {
- if (!e->ptype) {
- if (num == 0 && e->single.func == probe)
- return e->single.probe_private;
- } else {
- struct marker_probe_closure *closure;
- int match = 0;
- closure = e->multi;
- for (i = 0; closure[i].func; i++) {
- if (closure[i].func != probe)
- continue;
- if (match++ == num)
- return closure[i].probe_private;
- }
- }
- break;
- }
- }
- return ERR_PTR(-ENOENT);
-}
-EXPORT_SYMBOL_GPL(marker_get_private_data);
-
-#ifdef CONFIG_MODULES
-
-int marker_module_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct module *mod = data;
-
- switch (val) {
- case MODULE_STATE_COMING:
- marker_update_probe_range(mod->markers,
- mod->markers + mod->num_markers);
- break;
- case MODULE_STATE_GOING:
- marker_update_probe_range(mod->markers,
- mod->markers + mod->num_markers);
- break;
- }
- return 0;
-}
-
-struct notifier_block marker_module_nb = {
- .notifier_call = marker_module_notify,
- .priority = 0,
-};
-
-static int init_markers(void)
-{
- return register_module_notifier(&marker_module_nb);
-}
-__initcall(init_markers);
-
-#endif /* CONFIG_MODULES */
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-21 15:42:25 +0000