Re: [RFC][PATCH 04/12 v3] tracing: Convert seq_buf_path() to be like seq_path()

Steven Rostedt
2014-11-07T18:34:16Z

I made a few touch ups on this patch.

-- Steve

>From 309e8ce4cc1605d3038b16b8e43219a2867f47b1 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 29 Oct 2014 13:48:37 -0400
Subject: [PATCH] tracing: Convert seq_buf_path() to be like seq_path()

Rewrite seq_buf_path() like it is done in seq_path() and allow
it to accept any escape character instead of just "\n".

Making seq_buf_path() like seq_path() will help prevent problems
when converting seq_file to use the seq_buf logic.

Link: http://lkml.kernel.org/r/20141104160222.048795666@goodmis.org

Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/seq_buf.h | 2 +-
kernel/trace/seq_buf.c | 26 +++++++++++++++-----------
kernel/trace/trace_seq.c | 4 ++--
3 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 64bf5a43411e..aec09b126082 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -70,7 +70,7 @@ extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
unsigned int len);
-extern int seq_buf_path(struct seq_buf *s, const struct path *path);
+extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);

extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
int nmaskbits);
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
index 88738b200bf3..ac6eb864c946 100644
--- a/kernel/trace/seq_buf.c
+++ b/kernel/trace/seq_buf.c
@@ -272,28 +272,32 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
* seq_buf_path - copy a path into the sequence buffer
* @s: seq_buf descriptor
* @path: path to write into the sequence buffer.
+ * @esc: set of characters to escape in the output
*
* Write a path name into the sequence buffer.
*
* Returns zero on success, -1 on overflow
*/
-int seq_buf_path(struct seq_buf *s, const struct path *path)
+int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
{
- unsigned int len = seq_buf_buffer_left(s);
- unsigned char *p;
+ char *buf = s->buffer + s->len;
+ size_t size = seq_buf_buffer_left(s);
+ int res = -1;

WARN_ON(s->size == 0);

- p = d_path(path, s->buffer + s->len, len);
- if (!IS_ERR(p)) {
- p = mangle_path(s->buffer + s->len, p, "\n");
- if (p) {
- s->len = p - s->buffer;
- return 0;
+ if (size) {
+ char *p = d_path(path, buf, size);
+ if (!IS_ERR(p)) {
+ char *end = mangle_path(buf, p, esc);
+ if (end)
+ res = end - buf;
}
}
- seq_buf_set_overflow(s);
- return -1;
+ if (res > 0)
+ s->len += res;
+
+ return res;
}

/**
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 3ad8738aea19..64550ed28e76 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -382,7 +382,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
return 0;
}

- ret = seq_buf_path(&s->seq, path);
+ ret = seq_buf_path(&s->seq, path, "\n");

if (unlikely(seq_buf_has_overflowed(&s->seq))) {
s->seq.len = save_len;
@@ -390,7 +390,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path)
return 0;
}

- return ret;
+ return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_path);

--
2.1.1