tracing/events: Convert format output to seq_file
Two new events were added that broke the current format output. Both from the SCSI system: scsi_dispatch_cmd_done and scsi_dispatch_cmd_timeout The reason is that their print_fmt exceeded a page size. Since the output of the format used simple_read_from_buffer and trace_seq, it was limited to a page size in output. This patch converts the printing of the format of an event into seq_file, which allows greater than a page size to be shown. I diffed all event formats comparing the output with and without this patch. All matched except for the above two, which showed just: FORMAT TOO BIG without this patch, but now properly displays the output with this patch. v2: Remove updating *pos in seq start function. [ Thanks to Li Zefan for pointing that out ] Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Kei Tokunaga <tokunaga.keiich@jp.fujitsu.com> Cc: James Bottomley <James.Bottomley@suse.de> Cc: Tomohiro Kusumi <kusumi.tomohiro@jp.fujitsu.com> Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
Steven Rostedt
parent
465c6cca26
commit
2a37a3df57
1 changed files with 140 additions and 66 deletions
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@ -29,6 +29,8 @@ DEFINE_MUTEX(event_mutex);
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LIST_HEAD(ftrace_events);
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#define COMMON_FIELD_COUNT 5
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struct list_head *
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trace_get_fields(struct ftrace_event_call *event_call)
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{
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@ -544,85 +546,155 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
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return ret;
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}
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static ssize_t
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event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
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loff_t *ppos)
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enum {
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FORMAT_HEADER = 1,
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FORMAT_PRINTFMT = 2,
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};
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static void *f_next(struct seq_file *m, void *v, loff_t *pos)
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{
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struct ftrace_event_call *call = filp->private_data;
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struct ftrace_event_call *call = m->private;
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struct ftrace_event_field *field;
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struct list_head *head;
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struct trace_seq *s;
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int common_field_count = 5;
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char *buf;
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int r = 0;
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loff_t index = *pos;
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if (*ppos)
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return 0;
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s = kmalloc(sizeof(*s), GFP_KERNEL);
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if (!s)
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return -ENOMEM;
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trace_seq_init(s);
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trace_seq_printf(s, "name: %s\n", call->name);
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trace_seq_printf(s, "ID: %d\n", call->event.type);
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trace_seq_printf(s, "format:\n");
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(*pos)++;
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head = trace_get_fields(call);
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list_for_each_entry_reverse(field, head, link) {
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/*
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* Smartly shows the array type(except dynamic array).
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* Normal:
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* field:TYPE VAR
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* If TYPE := TYPE[LEN], it is shown:
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* field:TYPE VAR[LEN]
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*/
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const char *array_descriptor = strchr(field->type, '[');
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if (!strncmp(field->type, "__data_loc", 10))
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array_descriptor = NULL;
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switch ((unsigned long)v) {
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case FORMAT_HEADER:
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if (!array_descriptor) {
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r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
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"\tsize:%u;\tsigned:%d;\n",
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field->type, field->name, field->offset,
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field->size, !!field->is_signed);
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} else {
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r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
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"\tsize:%u;\tsigned:%d;\n",
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(int)(array_descriptor - field->type),
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field->type, field->name,
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array_descriptor, field->offset,
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field->size, !!field->is_signed);
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}
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if (unlikely(list_empty(head)))
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return NULL;
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if (--common_field_count == 0)
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r = trace_seq_printf(s, "\n");
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field = list_entry(head->prev, struct ftrace_event_field, link);
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return field;
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if (!r)
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break;
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case FORMAT_PRINTFMT:
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/* all done */
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return NULL;
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}
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if (r)
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r = trace_seq_printf(s, "\nprint fmt: %s\n",
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call->print_fmt);
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/*
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* To separate common fields from event fields, the
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* LSB is set on the first event field. Clear it in case.
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*/
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v = (void *)((unsigned long)v & ~1L);
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if (!r) {
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/*
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* ug! The format output is bigger than a PAGE!!
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*/
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buf = "FORMAT TOO BIG\n";
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r = simple_read_from_buffer(ubuf, cnt, ppos,
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buf, strlen(buf));
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goto out;
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field = v;
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if (field->link.prev == head)
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return (void *)FORMAT_PRINTFMT;
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field = list_entry(field->link.prev, struct ftrace_event_field, link);
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/* Set the LSB to notify f_show to print an extra newline */
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if (index == COMMON_FIELD_COUNT)
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field = (struct ftrace_event_field *)
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((unsigned long)field | 1);
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return field;
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}
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static void *f_start(struct seq_file *m, loff_t *pos)
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{
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loff_t l = 0;
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void *p;
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/* Start by showing the header */
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if (!*pos)
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return (void *)FORMAT_HEADER;
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p = (void *)FORMAT_HEADER;
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do {
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p = f_next(m, p, &l);
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} while (p && l < *pos);
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return p;
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}
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static int f_show(struct seq_file *m, void *v)
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{
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struct ftrace_event_call *call = m->private;
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struct ftrace_event_field *field;
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const char *array_descriptor;
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switch ((unsigned long)v) {
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case FORMAT_HEADER:
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seq_printf(m, "name: %s\n", call->name);
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seq_printf(m, "ID: %d\n", call->event.type);
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seq_printf(m, "format:\n");
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return 0;
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case FORMAT_PRINTFMT:
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seq_printf(m, "\nprint fmt: %s\n",
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call->print_fmt);
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return 0;
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}
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r = simple_read_from_buffer(ubuf, cnt, ppos,
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s->buffer, s->len);
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out:
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kfree(s);
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return r;
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/*
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* To separate common fields from event fields, the
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* LSB is set on the first event field. Clear it and
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* print a newline if it is set.
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*/
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if ((unsigned long)v & 1) {
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seq_putc(m, '\n');
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v = (void *)((unsigned long)v & ~1L);
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}
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field = v;
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/*
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* Smartly shows the array type(except dynamic array).
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* Normal:
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* field:TYPE VAR
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* If TYPE := TYPE[LEN], it is shown:
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* field:TYPE VAR[LEN]
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*/
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array_descriptor = strchr(field->type, '[');
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if (!strncmp(field->type, "__data_loc", 10))
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array_descriptor = NULL;
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if (!array_descriptor)
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seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
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field->type, field->name, field->offset,
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field->size, !!field->is_signed);
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else
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seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
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(int)(array_descriptor - field->type),
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field->type, field->name,
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array_descriptor, field->offset,
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field->size, !!field->is_signed);
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return 0;
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}
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static void f_stop(struct seq_file *m, void *p)
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{
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}
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static const struct seq_operations trace_format_seq_ops = {
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.start = f_start,
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.next = f_next,
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.stop = f_stop,
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.show = f_show,
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};
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static int trace_format_open(struct inode *inode, struct file *file)
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{
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struct ftrace_event_call *call = inode->i_private;
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struct seq_file *m;
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int ret;
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ret = seq_open(file, &trace_format_seq_ops);
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if (ret < 0)
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return ret;
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m = file->private_data;
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m->private = call;
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return 0;
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}
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static ssize_t
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@ -820,8 +892,10 @@ static const struct file_operations ftrace_enable_fops = {
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};
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static const struct file_operations ftrace_event_format_fops = {
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.open = tracing_open_generic,
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.read = event_format_read,
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.open = trace_format_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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static const struct file_operations ftrace_event_id_fops = {
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