1 files changed, 66 insertions, 14 deletions

diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 6b1c562ffdaf..32684ef4fb9d 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -13,12 +13,9 @@
  * trace_seq_init() more than once to reset the trace_seq to start
  * from scratch.
  * 
- * The buffer size is currently PAGE_SIZE, although it may become dynamic
- * in the future.
- *
- * A write to the buffer will either succed or fail. That is, unlike
+ * A write to the buffer will either succeed or fail. That is, unlike
  * sprintf() there will not be a partial write (well it may write into
- * the buffer but it wont update the pointers). This allows users to
+ * the buffer but it won't update the pointers). This allows users to
  * try to write something into the trace_seq buffer and if it fails
  * they can flush it and try again.
  *
@@ -30,9 +27,6 @@
 /* How much buffer is left on the trace_seq? */
 #define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)
 
-/* How much buffer is written? */
-#define TRACE_SEQ_BUF_USED(s) seq_buf_used(&(s)->seq)
-
 /*
  * trace_seq should work with being initialized with 0s.
  */
@@ -76,7 +70,7 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
  * @fmt: printf format string
  *
  * The tracer may use either sequence operations or its own
- * copy to user routines. To simplify formating of a trace
+ * copy to user routines. To simplify formatting of a trace
  * trace_seq_printf() is used to store strings into a special
  * buffer (@s). Then the output may be either used by
  * the sequencer or pulled into another buffer.
@@ -134,9 +128,10 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
  * trace_seq_vprintf - sequence printing of trace information
  * @s: trace sequence descriptor
  * @fmt: printf format string
+ * @args: Arguments for the format string
  *
  * The tracer may use either sequence operations or its own
- * copy to user routines. To simplify formating of a trace
+ * copy to user routines. To simplify formatting of a trace
  * trace_seq_printf is used to store strings into a special
  * buffer (@s). Then the output may be either used by
  * the sequencer or pulled into another buffer.
@@ -229,7 +224,7 @@ EXPORT_SYMBOL_GPL(trace_seq_puts);
  * @c: simple character to record
  *
  * The tracer may use either the sequence operations or its own
- * copy to user routines. This function records a simple charater
+ * copy to user routines. This function records a simple character
  * into a special buffer (@s) for later retrieval by a sequencer
  * or other mechanism.
  */
@@ -351,7 +346,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
 EXPORT_SYMBOL_GPL(trace_seq_path);
 
 /**
- * trace_seq_to_user - copy the squence buffer to user space
+ * trace_seq_to_user - copy the sequence buffer to user space
  * @s: trace sequence descriptor
  * @ubuf: The userspace memory location to copy to
  * @cnt: The amount to copy
@@ -366,13 +361,70 @@ EXPORT_SYMBOL_GPL(trace_seq_path);
  *
  * On failure it returns -EBUSY if all of the content in the
  * sequence has been already read, which includes nothing in the
- * sequenc (@s->len == @s->readpos).
+ * sequence (@s->len == @s->readpos).
  *
  * Returns -EFAULT if the copy to userspace fails.
  */
 int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
 {
+	int ret;
 	__trace_seq_init(s);
-	return seq_buf_to_user(&s->seq, ubuf, cnt);
+	ret = seq_buf_to_user(&s->seq, ubuf, s->readpos, cnt);
+	if (ret > 0)
+		s->readpos += ret;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(trace_seq_to_user);
+
+int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
+		       int prefix_type, int rowsize, int groupsize,
+		       const void *buf, size_t len, bool ascii)
+{
+	unsigned int save_len = s->seq.len;
+
+	if (s->full)
+		return 0;
+
+	__trace_seq_init(s);
+
+	if (TRACE_SEQ_BUF_LEFT(s) < 1) {
+		s->full = 1;
+		return 0;
+	}
+
+	seq_buf_hex_dump(&(s->seq), prefix_str,
+		   prefix_type, rowsize, groupsize,
+		   buf, len, ascii);
+
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+		return 0;
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL(trace_seq_hex_dump);
+
+/*
+ * trace_seq_acquire - acquire seq buffer with size len
+ * @s: trace sequence descriptor
+ * @len: size of buffer to be acquired
+ *
+ * acquire buffer with size of @len from trace_seq for output usage,
+ * user can fill string into that buffer.
+ *
+ * Returns start address of acquired buffer.
+ *
+ * it allow multiple usage in one trace output function call.
+ */
+char *trace_seq_acquire(struct trace_seq *s, unsigned int len)
+{
+	char *ret = trace_seq_buffer_ptr(s);
+
+	if (!WARN_ON_ONCE(seq_buf_buffer_left(&s->seq) < len))
+		seq_buf_commit(&s->seq, len);
+
+	return ret;
+}
+EXPORT_SYMBOL(trace_seq_acquire);