tracing: probeevent: Cleanup print argument functions

Cleanup the print-argument function to decouple it into
print-name and print-value, so that it can support more
flexible expression, like array type.

Link: http://lkml.kernel.org/r/152465859635.26224.13452846788717102315.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

4 files changed, 29 insertions, 31 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 508396edc56a..6326c71181aa 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1136,8 +1136,6 @@ print_kprobe_event(struct trace_iterator *iter, int flags,
         struct kprobe_trace_entry_head *field;
         struct trace_seq *s = &iter->seq;
         struct trace_probe *tp;
-        u8 *data;
-        int i;
 
         field = (struct kprobe_trace_entry_head *)iter->ent;
         tp = container_of(event, struct trace_probe, call.event);
@@ -1149,11 +1147,9 @@ print_kprobe_event(struct trace_iterator *iter, int flags,
 
         trace_seq_putc(s, ')');
 
-        data = (u8 *)&field[1];
-        for (i = 0; i < tp->nr_args; i++)
-                if (!tp->args[i].type->print(s, tp->args[i].name,
-                                             data + tp->args[i].offset, field))
-                        goto out;
+        if (print_probe_args(s, tp->args, tp->nr_args,
+                             (u8 *)&field[1], field) < 0)
+                goto out;
 
         trace_seq_putc(s, '\n');
  out:
@@ -1167,8 +1163,6 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,
         struct kretprobe_trace_entry_head *field;
         struct trace_seq *s = &iter->seq;
         struct trace_probe *tp;
-        u8 *data;
-        int i;
 
         field = (struct kretprobe_trace_entry_head *)iter->ent;
         tp = container_of(event, struct trace_probe, call.event);
@@ -1185,11 +1179,9 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,
 
         trace_seq_putc(s, ')');
 
-        data = (u8 *)&field[1];
-        for (i = 0; i < tp->nr_args; i++)
-                if (!tp->args[i].type->print(s, tp->args[i].name,
-                                             data + tp->args[i].offset, field))
-                        goto out;
+        if (print_probe_args(s, tp->args, tp->nr_args,
+                             (u8 *)&field[1], field) < 0)
+                goto out;
 
         trace_seq_putc(s, '\n');
 
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index e99c3ce7aa65..e2c184eaa7db 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -26,10 +26,9 @@ const char *reserved_field_names[] = {
 
 /* Printing  in basic type function template */
 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)                  \
-int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, const char *name,  \
-                                void *data, void *ent)                  \
+int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
 {                                                                       \
-        trace_seq_printf(s, " %s=" fmt, name, *(type *)data);           \
+        trace_seq_printf(s, fmt, *(type *)data);                        \
         return !trace_seq_has_overflowed(s);                            \
 }                                                                       \
 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;                          \
@@ -49,15 +48,14 @@ DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
 
 /* Print type function for string type */
-int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
-                                 void *data, void *ent)
+int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
 {
         int len = *(u32 *)data >> 16;
 
         if (!len)
-                trace_seq_printf(s, " %s=(fault)", name);
+                trace_seq_puts(s, "(fault)");
         else
-                trace_seq_printf(s, " %s=\"%s\"", name,
+                trace_seq_printf(s, "\"%s\"",
                                  (const char *)get_loc_data(data, ent));
         return !trace_seq_has_overflowed(s);
 }
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 03b10f3201a5..8254a061ac35 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -82,7 +82,7 @@ static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
 /* Data fetch function type */
 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
 /* Printing function type */
-typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
+typedef int (*print_type_func_t)(struct trace_seq *, void *, void *);
 
 /* Fetch types */
 enum {
@@ -124,8 +124,7 @@ typedef u32 string_size;
 
 /* Printing  in basic type function template */
 #define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
-int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
-                                void *data, void *ent);                 \
+int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, void *data, void *ent);\
 extern const char PRINT_TYPE_FMT_NAME(type)[]
 
 DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
@@ -403,6 +402,20 @@ store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
         }
 }
 
+static inline int
+print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
+                 u8 *data, void *field)
+{
+        int i;
+
+        for (i = 0; i < nr_args; i++) {
+                trace_seq_printf(s, " %s=", args[i].name);
+                if (!args[i].type->print(s, data + args[i].offset, field))
+                        return -ENOMEM;
+        }
+        return 0;
+}
+
 extern int set_print_fmt(struct trace_probe *tp, bool is_return);
 
 #ifdef CONFIG_PERF_EVENTS
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index d09638706fe0..c55753e1079e 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -892,7 +892,6 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
         struct trace_seq *s = &iter->seq;
         struct trace_uprobe *tu;
         u8 *data;
-        int i;
 
         entry = (struct uprobe_trace_entry_head *)iter->ent;
         tu = container_of(event, struct trace_uprobe, tp.call.event);
@@ -909,12 +908,8 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
                 data = DATAOF_TRACE_ENTRY(entry, false);
         }
 
-        for (i = 0; i < tu->tp.nr_args; i++) {
-                struct probe_arg *parg = &tu->tp.args[i];
-
-                if (!parg->type->print(s, parg->name, data + parg->offset, entry))
-                        goto out;
-        }
+        if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0)
+                goto out;
 
         trace_seq_putc(s, '\n');