tracing/events: introduce __dynamic_array()
__string() is limited:
- it's a char array, but we may want to define array with other types
- a source string should be available, but we may just know the string size
We introduce __dynamic_array() to break those limitations, and __string()
becomes a wrapper of it. As a side effect, now __get_str() can be used
in TP_fast_assign but not only TP_print.
Take XFS for example, we have the string length in the dirent, but the
string itself is not NULL-terminated, so __dynamic_array() can be used:
TRACE_EVENT(xfs_dir2,
TP_PROTO(struct xfs_da_args *args),
TP_ARGS(args),
TP_STRUCT__entry(
__field(int, namelen)
__dynamic_array(char, name, args->namelen + 1)
...
),
TP_fast_assign(
char *name = __get_str(name);
if (args->namelen)
memcpy(name, args->name, args->namelen);
name[args->namelen] = '\0';
__entry->namelen = args->namelen;
),
TP_printk("name %.*s namelen %d",
__entry->namelen ? __get_str(name) : NULL
__entry->namelen)
);
[ Impact: allow defining dynamic size arrays ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A2384D2.3080403@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Li Zefan
Steven Rostedt
Родитель
a9c1c3abe1
Коммит
7fcb7c472f
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@ -18,14 +18,17 @@
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#include <linux/ftrace_event.h>
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#undef __array
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#define __array(type, item, len) type item[len];
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#undef __field
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#define __field(type, item) type item;
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#undef __array
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#define __array(type, item, len) type item[len];
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#undef __dynamic_array
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#define __dynamic_array(type, item, len) unsigned short __data_loc_##item;
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#undef __string
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#define __string(item, src) unsigned short __str_loc_##item;
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#define __string(item, src) __dynamic_array(char, item, -1)
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#undef TP_STRUCT__entry
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#define TP_STRUCT__entry(args...) args
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@ -35,7 +38,7 @@
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struct ftrace_raw_##name { \
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struct trace_entry ent; \
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tstruct \
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char __str_data[0]; \
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char __data[0]; \
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}; \
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static struct ftrace_event_call event_##name
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@ -47,30 +50,31 @@
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*
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* Include the following:
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*
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* struct ftrace_str_offsets_<call> {
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* int <str1>;
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* int <str2>;
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* struct ftrace_data_offsets_<call> {
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* int <item1>;
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* int <item2>;
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* [...]
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* };
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*
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* The __string() macro will create each int <str>, this is to
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* keep the offset of each string from the beggining of the event
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* once we perform the strlen() of the src strings.
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*
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* The __dynamic_array() macro will create each int <item>, this is
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* to keep the offset of each array from the beginning of the event.
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*/
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#undef __array
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#define __array(type, item, len)
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#undef __field
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#define __field(type, item);
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#undef __array
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#define __array(type, item, len)
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#undef __dynamic_array
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#define __dynamic_array(type, item, len) int item;
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#undef __string
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#define __string(item, src) int item;
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#define __string(item, src) __dynamic_array(char, item, -1)
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
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struct ftrace_str_offsets_##call { \
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struct ftrace_data_offsets_##call { \
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tstruct; \
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};
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@ -119,8 +123,12 @@
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#undef TP_printk
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#define TP_printk(fmt, args...) fmt "\n", args
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#undef __get_dynamic_array
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#define __get_dynamic_array(field) \
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((void *)__entry + __entry->__data_loc_##field)
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#undef __get_str
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#define __get_str(field) ((char *)__entry + __entry->__str_loc_##field)
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#define __get_str(field) (char *)__get_dynamic_array(field)
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#undef __print_flags
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#define __print_flags(flag, delim, flag_array...) \
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@ -207,16 +215,19 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags) \
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if (!ret) \
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return 0;
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#undef __string
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#define __string(item, src) \
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ret = trace_seq_printf(s, "\tfield:__str_loc " #item ";\t" \
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#undef __dynamic_array
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#define __dynamic_array(type, item, len) \
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ret = trace_seq_printf(s, "\tfield:__data_loc " #item ";\t" \
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"offset:%u;\tsize:%u;\n", \
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(unsigned int)offsetof(typeof(field), \
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__str_loc_##item), \
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(unsigned int)sizeof(field.__str_loc_##item)); \
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__data_loc_##item), \
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(unsigned int)sizeof(field.__data_loc_##item)); \
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if (!ret) \
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return 0;
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#undef __string
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#define __string(item, src) __dynamic_array(char, item, -1)
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#undef __entry
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#define __entry REC
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@ -260,11 +271,14 @@ ftrace_format_##call(struct trace_seq *s) \
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if (ret) \
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return ret;
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#undef __dynamic_array
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#define __dynamic_array(type, item, len) \
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ret = trace_define_field(event_call, "__data_loc" "[" #type "]", #item,\
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offsetof(typeof(field), __data_loc_##item), \
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sizeof(field.__data_loc_##item), 0);
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#undef __string
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#define __string(item, src) \
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ret = trace_define_field(event_call, "__str_loc", #item, \
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offsetof(typeof(field), __str_loc_##item), \
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sizeof(field.__str_loc_##item), 0);
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#define __string(item, src) __dynamic_array(char, item, -1)
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, func, print) \
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@ -288,6 +302,43 @@ ftrace_define_fields_##call(void) \
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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/*
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* remember the offset of each array from the beginning of the event.
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*/
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#undef __entry
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#define __entry entry
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#undef __field
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#define __field(type, item)
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#undef __array
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#define __array(type, item, len)
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#undef __dynamic_array
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#define __dynamic_array(type, item, len) \
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__data_offsets->item = __data_size + \
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offsetof(typeof(*entry), __data); \
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__data_size += (len) * sizeof(type);
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#undef __string
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#define __string(item, src) __dynamic_array(char, item, strlen(src) + 1) \
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
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static inline int ftrace_get_offsets_##call( \
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struct ftrace_data_offsets_##call *__data_offsets, proto) \
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{ \
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int __data_size = 0; \
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struct ftrace_raw_##call __maybe_unused *entry; \
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\
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tstruct; \
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\
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return __data_size; \
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}
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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/*
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* Stage 4 of the trace events.
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*
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@ -432,15 +483,15 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
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#undef __array
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#define __array(type, item, len)
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#undef __dynamic_array
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#define __dynamic_array(type, item, len) \
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__entry->__data_loc_##item = __data_offsets.item;
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#undef __string
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#define __string(item, src) \
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__str_offsets.item = __str_size + \
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offsetof(typeof(*entry), __str_data); \
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__str_size += strlen(src) + 1;
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#define __string(item, src) __dynamic_array(char, item, -1) \
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#undef __assign_str
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#define __assign_str(dst, src) \
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__entry->__str_loc_##dst = __str_offsets.dst; \
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strcpy(__get_str(dst), src);
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#undef TRACE_EVENT
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@ -451,26 +502,29 @@ static struct ftrace_event_call event_##call; \
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\
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static void ftrace_raw_event_##call(proto) \
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{ \
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struct ftrace_str_offsets_##call __maybe_unused __str_offsets; \
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struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\
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struct ftrace_event_call *event_call = &event_##call; \
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struct ring_buffer_event *event; \
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struct ftrace_raw_##call *entry; \
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unsigned long irq_flags; \
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int __str_size = 0; \
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int __data_size; \
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int pc; \
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\
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local_save_flags(irq_flags); \
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pc = preempt_count(); \
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\
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tstruct; \
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__data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
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\
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event = trace_current_buffer_lock_reserve(event_##call.id, \
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sizeof(struct ftrace_raw_##call) + __str_size,\
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sizeof(*entry) + __data_size, \
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irq_flags, pc); \
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if (!event) \
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return; \
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entry = ring_buffer_event_data(event); \
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\
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\
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tstruct \
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\
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{ assign; } \
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\
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if (!filter_current_check_discard(event_call, entry, event)) \
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@ -478,12 +478,12 @@ enum {
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static int is_string_field(const char *type)
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{
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if (strstr(type, "__data_loc") && strstr(type, "char"))
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return FILTER_DYN_STRING;
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if (strchr(type, '[') && strstr(type, "char"))
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return FILTER_STATIC_STRING;
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if (!strcmp(type, "__str_loc"))
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return FILTER_DYN_STRING;
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return 0;
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}
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