markers: simplify marker_set_format()
current marker_set_format() is complex this patch simplify it, and decrease the overhead of marker_update_probes(). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -64,6 +64,7 @@ struct marker_entry {
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void *oldptr;
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void *oldptr;
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int rcu_pending;
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int rcu_pending;
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unsigned char ptype:1;
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unsigned char ptype:1;
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unsigned char format_allocated:1;
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char name[0]; /* Contains name'\0'format'\0' */
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char name[0]; /* Contains name'\0'format'\0' */
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};
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};
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@ -416,6 +417,7 @@ static struct marker_entry *add_marker(const char *name, const char *format)
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e->single.probe_private = NULL;
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e->single.probe_private = NULL;
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e->multi = NULL;
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e->multi = NULL;
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e->ptype = 0;
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e->ptype = 0;
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e->format_allocated = 0;
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e->refcount = 0;
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e->refcount = 0;
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e->rcu_pending = 0;
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e->rcu_pending = 0;
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hlist_add_head(&e->hlist, head);
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hlist_add_head(&e->hlist, head);
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@ -447,6 +449,8 @@ static int remove_marker(const char *name)
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if (e->single.func != __mark_empty_function)
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if (e->single.func != __mark_empty_function)
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return -EBUSY;
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return -EBUSY;
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hlist_del(&e->hlist);
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hlist_del(&e->hlist);
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if (e->format_allocated)
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kfree(e->format);
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/* Make sure the call_rcu has been executed */
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/* Make sure the call_rcu has been executed */
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if (e->rcu_pending)
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if (e->rcu_pending)
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rcu_barrier_sched();
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rcu_barrier_sched();
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@ -457,57 +461,34 @@ static int remove_marker(const char *name)
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/*
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/*
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* Set the mark_entry format to the format found in the element.
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* Set the mark_entry format to the format found in the element.
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*/
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*/
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static int marker_set_format(struct marker_entry **entry, const char *format)
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static int marker_set_format(struct marker_entry *entry, const char *format)
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{
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{
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struct marker_entry *e;
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entry->format = kstrdup(format, GFP_KERNEL);
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size_t name_len = strlen((*entry)->name) + 1;
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if (!entry->format)
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size_t format_len = strlen(format) + 1;
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e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
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GFP_KERNEL);
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if (!e)
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return -ENOMEM;
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return -ENOMEM;
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memcpy(&e->name[0], (*entry)->name, name_len);
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entry->format_allocated = 1;
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e->format = &e->name[name_len];
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memcpy(e->format, format, format_len);
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if (strcmp(e->format, MARK_NOARGS) == 0)
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e->call = marker_probe_cb_noarg;
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else
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e->call = marker_probe_cb;
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e->single = (*entry)->single;
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e->multi = (*entry)->multi;
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e->ptype = (*entry)->ptype;
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e->refcount = (*entry)->refcount;
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e->rcu_pending = 0;
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hlist_add_before(&e->hlist, &(*entry)->hlist);
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hlist_del(&(*entry)->hlist);
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/* Make sure the call_rcu has been executed */
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if ((*entry)->rcu_pending)
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rcu_barrier_sched();
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kfree(*entry);
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*entry = e;
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trace_mark(core_marker_format, "name %s format %s",
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trace_mark(core_marker_format, "name %s format %s",
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e->name, e->format);
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entry->name, entry->format);
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return 0;
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return 0;
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}
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}
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/*
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/*
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* Sets the probe callback corresponding to one marker.
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* Sets the probe callback corresponding to one marker.
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*/
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*/
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static int set_marker(struct marker_entry **entry, struct marker *elem,
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static int set_marker(struct marker_entry *entry, struct marker *elem,
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int active)
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int active)
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{
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{
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int ret;
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int ret;
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WARN_ON(strcmp((*entry)->name, elem->name) != 0);
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WARN_ON(strcmp(entry->name, elem->name) != 0);
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if ((*entry)->format) {
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if (entry->format) {
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if (strcmp((*entry)->format, elem->format) != 0) {
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if (strcmp(entry->format, elem->format) != 0) {
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printk(KERN_NOTICE
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printk(KERN_NOTICE
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"Format mismatch for probe %s "
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"Format mismatch for probe %s "
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"(%s), marker (%s)\n",
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"(%s), marker (%s)\n",
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(*entry)->name,
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entry->name,
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(*entry)->format,
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entry->format,
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elem->format);
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elem->format);
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return -EPERM;
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return -EPERM;
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}
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}
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@ -523,34 +504,33 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
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* pass from a "safe" callback (with argument) to an "unsafe"
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* pass from a "safe" callback (with argument) to an "unsafe"
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* callback (does not set arguments).
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* callback (does not set arguments).
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*/
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*/
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elem->call = (*entry)->call;
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elem->call = entry->call;
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/*
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/*
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* Sanity check :
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* Sanity check :
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* We only update the single probe private data when the ptr is
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* We only update the single probe private data when the ptr is
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* set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
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* set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
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*/
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*/
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WARN_ON(elem->single.func != __mark_empty_function
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WARN_ON(elem->single.func != __mark_empty_function
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&& elem->single.probe_private
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&& elem->single.probe_private != entry->single.probe_private
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!= (*entry)->single.probe_private &&
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&& !elem->ptype);
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!elem->ptype);
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elem->single.probe_private = entry->single.probe_private;
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elem->single.probe_private = (*entry)->single.probe_private;
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/*
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/*
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* Make sure the private data is valid when we update the
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* Make sure the private data is valid when we update the
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* single probe ptr.
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* single probe ptr.
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*/
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*/
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smp_wmb();
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smp_wmb();
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elem->single.func = (*entry)->single.func;
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elem->single.func = entry->single.func;
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/*
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/*
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* We also make sure that the new probe callbacks array is consistent
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* We also make sure that the new probe callbacks array is consistent
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* before setting a pointer to it.
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* before setting a pointer to it.
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*/
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*/
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rcu_assign_pointer(elem->multi, (*entry)->multi);
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rcu_assign_pointer(elem->multi, entry->multi);
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/*
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/*
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* Update the function or multi probe array pointer before setting the
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* Update the function or multi probe array pointer before setting the
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* ptype.
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* ptype.
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*/
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*/
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smp_wmb();
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smp_wmb();
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elem->ptype = (*entry)->ptype;
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elem->ptype = entry->ptype;
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elem->state = active;
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elem->state = active;
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return 0;
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return 0;
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@ -594,8 +574,7 @@ void marker_update_probe_range(struct marker *begin,
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for (iter = begin; iter < end; iter++) {
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for (iter = begin; iter < end; iter++) {
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mark_entry = get_marker(iter->name);
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mark_entry = get_marker(iter->name);
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if (mark_entry) {
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if (mark_entry) {
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set_marker(&mark_entry, iter,
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set_marker(mark_entry, iter, !!mark_entry->refcount);
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!!mark_entry->refcount);
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/*
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/*
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* ignore error, continue
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* ignore error, continue
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*/
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*/
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@ -657,7 +636,7 @@ int marker_probe_register(const char *name, const char *format,
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ret = PTR_ERR(entry);
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ret = PTR_ERR(entry);
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} else if (format) {
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} else if (format) {
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if (!entry->format)
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if (!entry->format)
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ret = marker_set_format(&entry, format);
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ret = marker_set_format(entry, format);
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else if (strcmp(entry->format, format))
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else if (strcmp(entry->format, format))
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ret = -EPERM;
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ret = -EPERM;
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}
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}
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