Re: [RFC][PATCH 03/12 v3] tracing: Create seq_buf layer in trace_seq

Steven Rostedt
2014-11-07T18:30:22Z

I'm not going to waist bandwidth reposting the entire series. Here's a
new version of this patch. I'm getting ready to pull it into my next
queue.

-- Steve

>From 11674c8df0580a03a2517e3a8e4705c47c663564 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 25 Jun 2014 15:54:42 -0400
Subject: [PATCH] tracing: Create seq_buf layer in trace_seq

Create a seq_buf layer that trace_seq sits on. The seq_buf will not
be limited to page size. This will allow other usages of seq_buf
instead of a hard set PAGE_SIZE one that trace_seq has.

Link: http://lkml.kernel.org/r/20141104160221.864997179@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 | 78 ++++++++
include/linux/trace_seq.h | 10 +-
kernel/trace/Makefile | 1 +
kernel/trace/seq_buf.c | 341 +++++++++++++++++++++++++++++++++++
kernel/trace/trace.c | 39 ++--
kernel/trace/trace_events.c | 6 +-
kernel/trace/trace_functions_graph.c | 6 +-
kernel/trace/trace_seq.c | 184 +++++++++----------
8 files changed, 540 insertions(+), 125 deletions(-)
create mode 100644 include/linux/seq_buf.h
create mode 100644 kernel/trace/seq_buf.c

diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
new file mode 100644
index 000000000000..64bf5a43411e
--- /dev/null
+++ b/include/linux/seq_buf.h
@@ -0,0 +1,78 @@
+#ifndef _LINUX_SEQ_BUF_H
+#define _LINUX_SEQ_BUF_H
+
+#include <linux/fs.h>
+
+/*
+ * Trace sequences are used to allow a function to call several other functions
+ * to create a string of data to use.
+ */
+
+/**
+ * seq_buf - seq buffer structure
+ * @buffer: pointer to the buffer
+ * @size: size of the buffer
+ * @len: the amount of data inside the buffer
+ * @readpos: The next position to read in the buffer.
+ */
+struct seq_buf {
+ unsigned char *buffer;
+ unsigned int size;
+ unsigned int len;
+ unsigned int readpos;
+};
+
+static inline void
+seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
+{
+ s->buffer = buf;
+ s->size = size;
+ s->len = 0;
+ s->readpos = 0;
+}
+
+/*
+ * seq_buf have a buffer that might overflow. When this happens
+ * the len and size are set to be equal.
+ */
+static inline bool
+seq_buf_has_overflowed(struct seq_buf *s)
+{
+ return s->len == s->size;
+}
+
+static inline void
+seq_buf_set_overflow(struct seq_buf *s)
+{
+ s->len = s->size;
+}
+
+/*
+ * How much buffer is left on the seq_buf?
+ */
+static inline unsigned int
+seq_buf_buffer_left(struct seq_buf *s)
+{
+ return (s->size - 1) - s->len;
+}
+
+extern __printf(2, 3)
+int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
+extern __printf(2, 0)
+int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
+extern int
+seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
+extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
+extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
+ int cnt);
+extern int seq_buf_puts(struct seq_buf *s, const char *str);
+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_bitmask(struct seq_buf *s, const unsigned long *maskp,
+ int nmaskbits);
+
+#endif /* _LINUX_SEQ_BUF_H */
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index ea6c9dea79e3..27c98fd76503 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -1,7 +1,7 @@
#ifndef _LINUX_TRACE_SEQ_H
#define _LINUX_TRACE_SEQ_H

-#include <linux/fs.h>
+#include <linux/seq_buf.h>

#include <asm/page.h>

@@ -12,16 +12,14 @@

struct trace_seq {
unsigned char buffer[PAGE_SIZE];
- unsigned int len;
- unsigned int readpos;
+ struct seq_buf seq;
int full;
};

static inline void
trace_seq_init(struct trace_seq *s)
{
- s->len = 0;
- s->readpos = 0;
+ seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);
s->full = 0;
}

@@ -37,7 +35,7 @@ trace_seq_init(struct trace_seq *s)
static inline unsigned char *
trace_seq_buffer_ptr(struct trace_seq *s)
{
- return s->buffer + s->len;
+ return s->buffer + s->seq.len;
}

/*
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 67d6369ddf83..edc98c72a634 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
obj-$(CONFIG_TRACING) += trace.o
obj-$(CONFIG_TRACING) += trace_output.o
obj-$(CONFIG_TRACING) += trace_seq.o
+obj-$(CONFIG_TRACING) += seq_buf.o
obj-$(CONFIG_TRACING) += trace_stat.o
obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c
new file mode 100644
index 000000000000..88738b200bf3
--- /dev/null
+++ b/kernel/trace/seq_buf.c
@@ -0,0 +1,341 @@
+/*
+ * seq_buf.c
+ *
+ * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * The seq_buf is a handy tool that allows you to pass a descriptor around
+ * to a buffer that other functions can write to. It is similar to the
+ * seq_file functionality but has some differences.
+ *
+ * To use it, the seq_buf must be initialized with seq_buf_init().
+ * This will set up the counters within the descriptor. You can call
+ * seq_buf_init() more than once to reset the seq_buf to start
+ * from scratch.
+ */
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+#include <linux/seq_buf.h>
+
+/* How much buffer is written? */
+#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1)
+
+/**
+ * seq_buf_print_seq - move the contents of seq_buf into a seq_file
+ * @m: the seq_file descriptor that is the destination
+ * @s: the seq_buf descriptor that is the source.
+ *
+ * Returns zero on success, non zero otherwise
+ */
+int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
+{
+ unsigned int len = SEQ_BUF_USED(s);
+
+ return seq_write(m, s->buffer, len);
+}
+
+/**
+ * seq_buf_vprintf - sequence printing of information.
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ * @args: va_list of arguments from a printf() type function
+ *
+ * Writes a vnprintf() format into the sequencce buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
+{
+ int len;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
+ if (s->len + len < s->size) {
+ s->len += len;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_printf - sequence printing of information
+ * @s: seq_buf descriptor
+ * @fmt: printf format string
+ *
+ * Writes a printf() format into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ va_start(ap, fmt);
+ ret = seq_buf_vprintf(s, fmt, ap);
+ va_end(ap);
+
+ return ret;
+}
+
+/**
+ * seq_buf_bitmask - write a bitmask array in its ASCII representation
+ * @s: seq_buf descriptor
+ * @maskp: points to an array of unsigned longs that represent a bitmask
+ * @nmaskbits: The number of bits that are valid in @maskp
+ *
+ * Writes a ASCII representation of a bitmask string into @s.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
+ int nmaskbits)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ /*
+ * The last byte of the buffer is used to determine if we
+ * overflowed or not.
+ */
+ if (len > 1) {
+ ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
+ if (ret < len) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_bprintf - Write the printf string from binary arguments
+ * @s: seq_buf descriptor
+ * @fmt: The format string for the @binary arguments
+ * @binary: The binary arguments for @fmt.
+ *
+ * When recording in a fast path, a printf may be recorded with just
+ * saving the format and the arguments as they were passed to the
+ * function, instead of wasting cycles converting the arguments into
+ * ASCII characters. Instead, the arguments are saved in a 32 bit
+ * word array that is defined by the format string constraints.
+ *
+ * This function will take the format and the binary array and finish
+ * the conversion into the ASCII string within the buffer.
+ *
+ * Returns zero on success, -1 on overflow.
+ */
+int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ int ret;
+
+ WARN_ON(s->size == 0);
+
+ if (s->len < s->size) {
+ ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ if (s->len + ret < s->size) {
+ s->len += ret;
+ return 0;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_puts - sequence printing of simple string
+ * @s: seq_buf descriptor
+ * @str: simple string to record
+ *
+ * Copy a simple string into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_puts(struct seq_buf *s, const char *str)
+{
+ unsigned int len = strlen(str);
+
+ WARN_ON(s->size == 0);
+
+ if (s->len + len < s->size) {
+ memcpy(s->buffer + s->len, str, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putc - sequence printing of simple character
+ * @s: seq_buf descriptor
+ * @c: simple character to record
+ *
+ * Copy a single character into the sequence buffer.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putc(struct seq_buf *s, unsigned char c)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + 1 < s->size) {
+ s->buffer[s->len++] = c;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_putmem - write raw data into the sequenc buffer
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to copy into the buffer
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * There may be cases where raw memory needs to be written into the
+ * buffer and a strcpy() would not work. Using this function allows
+ * for such cases.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
+{
+ WARN_ON(s->size == 0);
+
+ if (s->len + len < s->size) {
+ memcpy(s->buffer + s->len, mem, len);
+ s->len += len;
+ return 0;
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+#define MAX_MEMHEX_BYTES 8U
+#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
+
+/**
+ * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
+ * @s: seq_buf descriptor
+ * @mem: The raw memory to write its hex ASCII representation of
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * This is similar to seq_buf_putmem() except instead of just copying the
+ * raw memory into the buffer it writes its ASCII representation of it
+ * in hex characters.
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
+ unsigned int len)
+{
+ unsigned char hex[HEX_CHARS];
+ const unsigned char *data = mem;
+ unsigned int start_len;
+ int i, j;
+
+ WARN_ON(s->size == 0);
+
+ while (len) {
+ start_len = min(len, HEX_CHARS - 1);
+#ifdef __BIG_ENDIAN
+ for (i = 0, j = 0; i < start_len; i++) {
+#else
+ for (i = start_len-1, j = 0; i >= 0; i--) {
+#endif
+ hex[j++] = hex_asc_hi(data[i]);
+ hex[j++] = hex_asc_lo(data[i]);
+ }
+ if (WARN_ON_ONCE(j == 0 || j/2 > len))
+ break;
+
+ /* j increments twice per loop */
+ len -= j / 2;
+ hex[j++] = ' ';
+
+ seq_buf_putmem(s, hex, j);
+ if (seq_buf_has_overflowed(s))
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * seq_buf_path - copy a path into the sequence buffer
+ * @s: seq_buf descriptor
+ * @path: path to write into the sequence buffer.
+ *
+ * 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)
+{
+ unsigned int len = seq_buf_buffer_left(s);
+ unsigned char *p;
+
+ 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;
+ }
+ }
+ seq_buf_set_overflow(s);
+ return -1;
+}
+
+/**
+ * seq_buf_to_user - copy the squence buffer to user space
+ * @s: seq_buf descriptor
+ * @ubuf: The userspace memory location to copy to
+ * @cnt: The amount to copy
+ *
+ * Copies the sequence buffer into the userspace memory pointed to
+ * by @ubuf. It starts from the last read position (@s->readpos)
+ * and writes up to @cnt characters or till it reaches the end of
+ * the content in the buffer (@s->len), which ever comes first.
+ *
+ * On success, it returns a positive number of the number of bytes
+ * it copied.
+ *
+ * On failure it returns -EBUSY if all of the content in the
+ * sequence has been already read, which includes nothing in the
+ * sequence (@s->len == @s->readpos).
+ *
+ * Returns -EFAULT if the copy to userspace fails.
+ */
+int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
+{
+ int len;
+ int ret;
+
+ if (!cnt)
+ return 0;
+
+ if (s->len <= s->readpos)
+ return -EBUSY;
+
+ len = s->len - s->readpos;
+ if (cnt > len)
+ cnt = len;
+ ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
+ if (ret == cnt)
+ return -EFAULT;
+
+ cnt -= ret;
+
+ s->readpos += cnt;
+ return cnt;
+}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8a528392b1f4..0c46168e938e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -938,19 +938,20 @@ out:
return ret;
}

+/* TODO add a seq_buf_to_buffer() */
static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;

- if (s->len <= s->readpos)
+ if (s->seq.len <= s->seq.readpos)
return -EBUSY;

- len = s->len - s->readpos;
+ len = s->seq.len - s->seq.readpos;
if (cnt > len)
cnt = len;
- memcpy(buf, s->buffer + s->readpos, cnt);
+ memcpy(buf, s->buffer + s->seq.readpos, cnt);

- s->readpos += cnt;
+ s->seq.readpos += cnt;
return cnt;
}

@@ -4313,6 +4314,8 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
goto out;
}

+ trace_seq_init(&iter->seq);
+
/*
* We make a copy of the current tracer to avoid concurrent
* changes on it while we are reading.
@@ -4509,18 +4512,18 @@ waitagain:
trace_access_lock(iter->cpu_file);
while (trace_find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
- int len = iter->seq.len;
+ int len = iter->seq.seq.len;

ret = print_trace_line(iter);
if (ret == TRACE_TYPE_PARTIAL_LINE) {
/* don't print partial lines */
- iter->seq.len = len;
+ iter->seq.seq.len = len;
break;
}
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(iter);

- if (iter->seq.len >= cnt)
+ if (iter->seq.seq.len >= cnt)
break;

/*
@@ -4536,7 +4539,7 @@ waitagain:

/* Now copy what we have to the user */
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
- if (iter->seq.readpos >= iter->seq.len)
+ if (iter->seq.seq.readpos >= iter->seq.seq.len)
trace_seq_init(&iter->seq);

/*
@@ -4574,16 +4577,16 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)

/* Seq buffer is page-sized, exactly what we need. */
for (;;) {
- count = iter->seq.len;
+ count = iter->seq.seq.len;
ret = print_trace_line(iter);
- count = iter->seq.len - count;
+ count = iter->seq.seq.len - count;
if (rem < count) {
rem = 0;
- iter->seq.len -= count;
+ iter->seq.seq.len -= count;
break;
}
if (ret == TRACE_TYPE_PARTIAL_LINE) {
- iter->seq.len -= count;
+ iter->seq.seq.len -= count;
break;
}

@@ -4664,13 +4667,13 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
/* Copy the data into the page, so we can start over. */
ret = trace_seq_to_buffer(&iter->seq,
page_address(spd.pages[i]),
- iter->seq.len);
+ iter->seq.seq.len);
if (ret < 0) {
__free_page(spd.pages[i]);
break;
}
spd.partial[i].offset = 0;
- spd.partial[i].len = iter->seq.len;
+ spd.partial[i].len = iter->seq.seq.len;

trace_seq_init(&iter->seq);
}
@@ -5671,7 +5674,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
trace_seq_printf(s, "read events: %ld\n", cnt);

- count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
+ count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->seq.len);

kfree(s);

@@ -6634,11 +6637,11 @@ void
trace_printk_seq(struct trace_seq *s)
{
/* Probably should print a warning here. */
- if (s->len >= TRACE_MAX_PRINT)
- s->len = TRACE_MAX_PRINT;
+ if (s->seq.len >= TRACE_MAX_PRINT)
+ s->seq.len = TRACE_MAX_PRINT;

/* should be zero ended, but we are paranoid. */
- s->buffer[s->len] = 0;
+ s->buffer[s->seq.len] = 0;

printk(KERN_TRACE "%s", s->buffer);

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 0cc51edde3a8..33525bf6cbf5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1044,7 +1044,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
mutex_unlock(&event_mutex);

if (file)
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);

kfree(s);

@@ -1210,7 +1210,7 @@ subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
trace_seq_init(s);

print_subsystem_event_filter(system, s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);

kfree(s);

@@ -1265,7 +1265,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
trace_seq_init(s);

func(s);
- r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+ r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->seq.len);

kfree(s);

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index f0a0c982cde3..488273458bfd 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1291,9 +1291,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
}

/* Strip ending newline */
- if (s->buffer[s->len - 1] == '\n') {
- s->buffer[s->len - 1] = '\0';
- s->len--;
+ if (s->buffer[s->seq.len - 1] == '\n') {
+ s->buffer[s->seq.len - 1] = '\0';
+ s->seq.len--;
}

ret = trace_seq_puts(s, " */\n");
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 1f24ed99dca2..3ad8738aea19 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -27,10 +27,19 @@
#include <linux/trace_seq.h>

/* How much buffer is left on the trace_seq? */
-#define TRACE_SEQ_BUF_LEFT(s) ((PAGE_SIZE - 1) - (s)->len)
+#define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)

/* How much buffer is written? */
-#define TRACE_SEQ_BUF_USED(s) min((s)->len, (unsigned int)(PAGE_SIZE - 1))
+#define TRACE_SEQ_BUF_USED(s) min((s)->seq.len, (unsigned int)(PAGE_SIZE - 1))
+
+/*
+ * trace_seq should work with being initialized with 0s.
+ */
+static inline void __trace_seq_init(struct trace_seq *s)
+{
+ if (unlikely(!s->seq.size))
+ trace_seq_init(s);
+}

/**
* trace_print_seq - move the contents of trace_seq into a seq_file
@@ -43,10 +52,11 @@
*/
int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
- unsigned int len = TRACE_SEQ_BUF_USED(s);
int ret;

- ret = seq_write(m, s->buffer, len);
+ __trace_seq_init(s);
+
+ ret = seq_buf_print_seq(m, &s->seq);

/*
* Only reset this buffer if we successfully wrote to the
@@ -77,25 +87,25 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
*/
int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
va_list ap;
- int ret;

- if (s->full || !len)
+ if (s->full)
return 0;

+ __trace_seq_init(s);
+
va_start(ap, fmt);
- ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
+ seq_buf_vprintf(&s->seq, fmt, ap);
va_end(ap);

/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return 0;
}

- s->len += ret;
-
return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);
@@ -116,14 +126,20 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
- int ret;
+ unsigned int save_len = s->seq.len;

- if (s->full || !len)
+ if (s->full)
return 0;

- ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
- s->len += ret;
+ __trace_seq_init(s);
+
+ seq_buf_bitmask(&s->seq, maskp, nmaskbits);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return 0;
+ }

return 1;
}
@@ -144,23 +160,24 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
*/
int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
int ret;

- if (s->full || !len)
+ if (s->full)
return 0;

- ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+ __trace_seq_init(s);
+
+ ret = seq_buf_vprintf(&s->seq, fmt, args);

/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return 0;
}

- s->len += ret;
-
- return len;
+ return ret;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);

@@ -183,23 +200,24 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
*/
int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
int ret;

- if (s->full || !len)
+ if (s->full)
return 0;

- ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ __trace_seq_init(s);
+
+ ret = seq_buf_bprintf(&s->seq, fmt, binary);

/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return 0;
}

- s->len += ret;
-
- return len;
+ return ret;
}
EXPORT_SYMBOL_GPL(trace_seq_bprintf);

@@ -222,13 +240,14 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
if (s->full)
return 0;

+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return 0;
}

- memcpy(s->buffer + s->len, str, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, str, len);

return len;
}
@@ -251,12 +270,14 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c)
if (s->full)
return 0;

+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return 0;
}

- s->buffer[s->len++] = c;
+ seq_buf_putc(&s->seq, c);

return 1;
}
@@ -279,21 +300,19 @@ int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
if (s->full)
return 0;

+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return 0;
}

- memcpy(s->buffer + s->len, mem, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, mem, len);

return len;
}
EXPORT_SYMBOL_GPL(trace_seq_putmem);

-#define MAX_MEMHEX_BYTES 8U
-#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
-
/**
* trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex
* @s: trace sequence descriptor
@@ -309,35 +328,30 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
- unsigned char hex[HEX_CHARS];
- const unsigned char *data = mem;
- unsigned int start_len;
- int i, j;
- int cnt = 0;
+ unsigned int save_len = s->seq.len;
+ int ret;

if (s->full)
return 0;

- while (len) {
- start_len = min(len, HEX_CHARS - 1);
-#ifdef __BIG_ENDIAN
- for (i = 0, j = 0; i < start_len; i++) {
-#else
- for (i = start_len-1, j = 0; i >= 0; i--) {
-#endif
- hex[j++] = hex_asc_hi(data[i]);
- hex[j++] = hex_asc_lo(data[i]);
- }
- if (WARN_ON_ONCE(j == 0 || j/2 > len))
- break;
-
- /* j increments twice per loop */
- len -= j / 2;
- hex[j++] = ' ';
-
- cnt += trace_seq_putmem(s, hex, j);
+ __trace_seq_init(s);
+
+ /* Each byte is represented by two chars */
+ if (len * 2 > TRACE_SEQ_BUF_LEFT(s)) {
+ s->full = 1;
+ return 0;
+ }
+
+ /* The added spaces can still cause an overflow */
+ ret = seq_buf_putmem_hex(&s->seq, mem, len);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return 0;
}
- return cnt;
+
+ return ret;
}
EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);

@@ -355,30 +369,28 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
*/
int trace_seq_path(struct trace_seq *s, const struct path *path)
{
- unsigned char *p;
+ unsigned int save_len = s->seq.len;
+ int ret;

if (s->full)
return 0;

+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return 0;
}

- p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
- if (!IS_ERR(p)) {
- p = mangle_path(s->buffer + s->len, p, "\n");
- if (p) {
- s->len = p - s->buffer;
- return 1;
- }
- } else {
- s->buffer[s->len++] = '?';
- return 1;
+ ret = seq_buf_path(&s->seq, path);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return 0;
}

- s->full = 1;
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(trace_seq_path);

@@ -404,25 +416,7 @@ EXPORT_SYMBOL_GPL(trace_seq_path);
*/
int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
{
- int len;
- int ret;
-
- if (!cnt)
- return 0;
-
- if (s->len <= s->readpos)
- return -EBUSY;
-
- len = s->len - s->readpos;
- if (cnt > len)
- cnt = len;
- ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
- if (ret == cnt)
- return -EFAULT;
-
- cnt -= ret;
-
- s->readpos += cnt;
- return cnt;
+ __trace_seq_init(s);
+ return seq_buf_to_user(&s->seq, ubuf, cnt);
}
EXPORT_SYMBOL_GPL(trace_seq_to_user);
--
2.1.1