tracing: Add trace_array_puts() to write into instance

Add a generic trace_array_puts() that can be used to "trace_puts()" into
an allocated trace_array instance. This is just another variant of
trace_array_printk().

Link: https://lkml.kernel.org/r/20230207173026.584717290@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/include/linux/trace.h b/include/linux/trace.h
index 80ffda8..2a70a44 100644 (file)
--- a/include/linux/trace.h
+++ b/include/linux/trace.h
@@ -33,6 +33,18 @@ struct trace_array;
 int register_ftrace_export(struct trace_export *export);
 int unregister_ftrace_export(struct trace_export *export);
 
+/**
+ * trace_array_puts - write a constant string into the trace buffer.
+ * @tr:    The trace array to write to
+ * @str:   The constant string to write
+ */
+#define trace_array_puts(tr, str)                                      \
+       ({                                                              \
+               str ? __trace_array_puts(tr, _THIS_IP_, str, strlen(str)) : -1; \
+       })
+int __trace_array_puts(struct trace_array *tr, unsigned long ip,
+                      const char *str, int size);
+
 void trace_printk_init_buffers(void);
 __printf(3, 4)
 int trace_array_printk(struct trace_array *tr, unsigned long ip,

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5b16af9..9918bf7 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1023,13 +1023,8 @@ __buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *ev
                ring_buffer_unlock_commit(buffer);
 }
 
-/**
- * __trace_puts - write a constant string into the trace buffer.
- * @ip:           The address of the caller
- * @str:   The constant string to write
- * @size:  The size of the string.
- */
-int __trace_puts(unsigned long ip, const char *str, int size)
+int __trace_array_puts(struct trace_array *tr, unsigned long ip,
+                      const char *str, int size)
 {
        struct ring_buffer_event *event;
        struct trace_buffer *buffer;
@@ -1037,7 +1032,7 @@ int __trace_puts(unsigned long ip, const char *str, int size)
        unsigned int trace_ctx;
        int alloc;
 
-       if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+       if (!(tr->trace_flags & TRACE_ITER_PRINTK))
                return 0;
 
        if (unlikely(tracing_selftest_running || tracing_disabled))
@@ -1046,7 +1041,7 @@ int __trace_puts(unsigned long ip, const char *str, int size)
        alloc = sizeof(*entry) + size + 2; /* possible \n added */
 
        trace_ctx = tracing_gen_ctx();
-       buffer = global_trace.array_buffer.buffer;
+       buffer = tr->array_buffer.buffer;
        ring_buffer_nest_start(buffer);
        event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
                                            trace_ctx);
@@ -1068,11 +1063,23 @@ int __trace_puts(unsigned long ip, const char *str, int size)
                entry->buf[size] = '\0';
 
        __buffer_unlock_commit(buffer, event);
-       ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
+       ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
  out:
        ring_buffer_nest_end(buffer);
        return size;
 }
+EXPORT_SYMBOL_GPL(__trace_array_puts);
+
+/**
+ * __trace_puts - write a constant string into the trace buffer.
+ * @ip:           The address of the caller
+ * @str:   The constant string to write
+ * @size:  The size of the string.
+ */
+int __trace_puts(unsigned long ip, const char *str, int size)
+{
+       return __trace_array_puts(&global_trace, ip, str, size);
+}
 EXPORT_SYMBOL_GPL(__trace_puts);
 
 /**