ftrace: fix trace_output

Impact: fix bug for handling partial line

trace_seq_printf(), seq_print_userip_objs(), ... return
0          -- partial line was written
other(>0)  -- success

duplicate output is also removed in trace_print_raw().

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 33 insertions, 36 deletions

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index df0c25cbed30..4e3ad36b117c 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -440,9 +440,9 @@ trace_fn_raw(struct trace_seq *s, struct trace_entry *entry, int flags)
 
         trace_assign_type(field, entry);
 
-        if (trace_seq_printf(s, "%x %x\n",
-                             field->ip,
-                             field->parent_ip))
+        if (!trace_seq_printf(s, "%x %x\n",
+                              field->ip,
+                              field->parent_ip))
                 return TRACE_TYPE_PARTIAL_LINE;
 
         return 0;
@@ -497,14 +497,14 @@ trace_ctxwake_print(struct trace_seq *s, struct trace_entry *entry, int flags,
         T = task_state_char(field->next_state);
         S = task_state_char(field->prev_state);
         comm = trace_find_cmdline(field->next_pid);
-        if (trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
-                             field->prev_pid,
-                             field->prev_prio,
-                             S, delim,
-                             field->next_cpu,
-                             field->next_pid,
-                             field->next_prio,
-                             T, comm))
+        if (!trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
+                              field->prev_pid,
+                              field->prev_prio,
+                              S, delim,
+                              field->next_cpu,
+                              field->next_pid,
+                              field->next_prio,
+                              T, comm))
                 return TRACE_TYPE_PARTIAL_LINE;
 
         return 0;
@@ -534,14 +534,14 @@ trace_ctxwake_raw(struct trace_seq *s, struct trace_entry *entry, int flags,
         if (!S)
                 task_state_char(field->prev_state);
         T = task_state_char(field->next_state);
-        if (trace_seq_printf(s, "%d %d %c %d %d %d %c\n",
-                             field->prev_pid,
-                             field->prev_prio,
-                             S,
-                             field->next_cpu,
-                             field->next_pid,
-                             field->next_prio,
-                             T))
+        if (!trace_seq_printf(s, "%d %d %c %d %d %d %c\n",
+                              field->prev_pid,
+                              field->prev_prio,
+                              S,
+                              field->next_cpu,
+                              field->next_pid,
+                              field->next_prio,
+                              T))
                 return TRACE_TYPE_PARTIAL_LINE;
 
         return 0;
@@ -639,10 +639,10 @@ trace_special_print(struct trace_seq *s, struct trace_entry *entry, int flags)
 
         trace_assign_type(field, entry);
 
-        if (trace_seq_printf(s, "# %ld %ld %ld\n",
-                             field->arg1,
-                             field->arg2,
-                             field->arg3))
+        if (!trace_seq_printf(s, "# %ld %ld %ld\n",
+                              field->arg1,
+                              field->arg2,
+                              field->arg3))
                 return TRACE_TYPE_PARTIAL_LINE;
 
         return 0;
@@ -697,13 +697,13 @@ trace_stack_print(struct trace_seq *s, struct trace_entry *entry, int flags)
 
         for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
                 if (i) {
-                        if (trace_seq_puts(s, " <= "))
+                        if (!trace_seq_puts(s, " <= "))
                                 goto partial;
 
-                        if (seq_print_ip_sym(s, field->caller[i], flags))
+                        if (!seq_print_ip_sym(s, field->caller[i], flags))
                                 goto partial;
                 }
-                if (trace_seq_puts(s, "\n"))
+                if (!trace_seq_puts(s, "\n"))
                         goto partial;
         }
 
@@ -731,10 +731,10 @@ trace_user_stack_print(struct trace_seq *s, struct trace_entry *entry,
 
         trace_assign_type(field, entry);
 
-        if (seq_print_userip_objs(field, s, flags))
+        if (!seq_print_userip_objs(field, s, flags))
                 goto partial;
 
-        if (trace_seq_putc(s, '\n'))
+        if (!trace_seq_putc(s, '\n'))
                 goto partial;
 
         return 0;
@@ -760,10 +760,10 @@ trace_print_print(struct trace_seq *s, struct trace_entry *entry, int flags)
 
         trace_assign_type(field, entry);
 
-        if (seq_print_ip_sym(s, field->ip, flags))
+        if (!seq_print_ip_sym(s, field->ip, flags))
                 goto partial;
 
-        if (trace_seq_printf(s, ": %s", field->buf))
+        if (!trace_seq_printf(s, ": %s", field->buf))
                 goto partial;
 
         return 0;
@@ -779,10 +779,7 @@ trace_print_raw(struct trace_seq *s, struct trace_entry *entry, int flags)
 
         trace_assign_type(field, entry);
 
-        if (seq_print_ip_sym(s, field->ip, flags))
-                goto partial;
-
-        if (trace_seq_printf(s, "# %lx %s", field->ip, field->buf))
+        if (!trace_seq_printf(s, "# %lx %s", field->ip, field->buf))
                 goto partial;
 
         return 0;
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index ecab4ea4a4fd..b2c14615e0cd 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -45,14 +45,14 @@ trace_nop_print(struct trace_seq *s, struct trace_entry *entry, int flags);
 #define SEQ_PUT_FIELD_RET(s, x)                         \
 do {                                                    \
         if (!trace_seq_putmem(s, &(x), sizeof(x)))      \
-                return 0;                               \
+                return TRACE_TYPE_PARTIAL_LINE;         \
 } while (0)
 
 #define SEQ_PUT_HEX_FIELD_RET(s, x)                     \
 do {                                                    \
         BUILD_BUG_ON(sizeof(x) > MAX_MEMHEX_BYTES);     \
         if (!trace_seq_putmem_hex(s, &(x), sizeof(x)))  \
-                return 0;                               \
+                return TRACE_TYPE_PARTIAL_LINE;         \
 } while (0)
 
 #endif