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Subject[PATCH v4 33/34] tracing: Convert to printbuf
Date
This converts the seq_bufs in dynevent_cmd and trace_seq to printbufs.

- read_pos in seq_buf doesn't exist in printbuf, so is added to
trace_seq

- seq_buf_to_user doesn't have a printbuf equivalent, so is inlined
into trace_seq_to_user

- seq_buf_putmem_hex currently swabs bytes on little endian, hardcoded
to 8 byte units. This patch switches it to prt_hex_bytes(), which
does _not_ swab.

Otherwise this is largely a direct conversion, with a few slight
refactorings and cleanups.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
include/linux/trace_events.h | 2 +-
include/linux/trace_seq.h | 17 ++--
kernel/trace/trace.c | 45 ++++-------
kernel/trace/trace_dynevent.c | 34 ++++----
kernel/trace/trace_events_filter.c | 2 +-
kernel/trace/trace_events_synth.c | 2 +-
kernel/trace/trace_functions_graph.c | 6 +-
kernel/trace/trace_kprobe.c | 2 +-
kernel/trace/trace_seq.c | 111 ++++++++++++++-------------
9 files changed, 103 insertions(+), 118 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index e6e95a9f07..48471e32f8 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -496,7 +496,7 @@ struct dynevent_cmd;
typedef int (*dynevent_create_fn_t)(struct dynevent_cmd *cmd);

struct dynevent_cmd {
- struct seq_buf seq;
+ struct printbuf seq;
const char *event_name;
unsigned int n_fields;
enum dynevent_type type;
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 5a2c650d9e..d2b51007b3 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -2,10 +2,12 @@
#ifndef _LINUX_TRACE_SEQ_H
#define _LINUX_TRACE_SEQ_H

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

#include <asm/page.h>

+struct seq_file;
+
/*
* Trace sequences are used to allow a function to call several other functions
* to create a string of data to use (up to a max of PAGE_SIZE).
@@ -13,14 +15,16 @@

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

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

@@ -39,7 +43,7 @@ trace_seq_init(struct trace_seq *s)
*/
static inline int trace_seq_used(struct trace_seq *s)
{
- return seq_buf_used(&s->seq);
+ return printbuf_written(&s->seq);
}

/**
@@ -54,7 +58,7 @@ static inline int trace_seq_used(struct trace_seq *s)
static inline char *
trace_seq_buffer_ptr(struct trace_seq *s)
{
- return s->buffer + seq_buf_used(&s->seq);
+ return s->buffer + printbuf_written(&s->seq);
}

/**
@@ -66,7 +70,7 @@ trace_seq_buffer_ptr(struct trace_seq *s)
*/
static inline bool trace_seq_has_overflowed(struct trace_seq *s)
{
- return s->full || seq_buf_has_overflowed(&s->seq);
+ return s->full || printbuf_overflowed(&s->seq);
}

/*
@@ -87,6 +91,7 @@ extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len);
+struct path;
extern int trace_seq_path(struct trace_seq *s, const struct path *path);

extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f4de111fa1..b815a914b5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1670,15 +1670,15 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;

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

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

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

@@ -3725,11 +3725,7 @@ static bool trace_safe_str(struct trace_iterator *iter, const char *str,

static const char *show_buffer(struct trace_seq *s)
{
- struct seq_buf *seq = &s->seq;
-
- seq_buf_terminate(seq);
-
- return seq->buffer;
+ return printbuf_str(&s->seq);
}

static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
@@ -6762,12 +6758,12 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
trace_access_lock(iter->cpu_file);
while (trace_find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
- int save_len = iter->seq.seq.len;
+ int save_pos = iter->seq.seq.pos;

ret = print_trace_line(iter);
if (ret == TRACE_TYPE_PARTIAL_LINE) {
/* don't print partial lines */
- iter->seq.seq.len = save_len;
+ iter->seq.seq.pos = save_pos;
break;
}
if (ret != TRACE_TYPE_NO_CONSUME)
@@ -6789,7 +6785,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,

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

/*
@@ -6815,16 +6811,15 @@ static size_t
tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
{
size_t count;
- int save_len;
int ret;

/* Seq buffer is page-sized, exactly what we need. */
for (;;) {
- save_len = iter->seq.seq.len;
+ unsigned save_pos = iter->seq.seq.pos;
ret = print_trace_line(iter);

if (trace_seq_has_overflowed(&iter->seq)) {
- iter->seq.seq.len = save_len;
+ iter->seq.seq.pos = save_pos;
break;
}

@@ -6834,14 +6829,14 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
* anyway to be safe.
*/
if (ret == TRACE_TYPE_PARTIAL_LINE) {
- iter->seq.seq.len = save_len;
+ iter->seq.seq.pos = save_pos;
break;
}

- count = trace_seq_used(&iter->seq) - save_len;
+ count = trace_seq_used(&iter->seq) - save_pos;
if (rem < count) {
rem = 0;
- iter->seq.seq.len = save_len;
+ iter->seq.seq.pos = save_pos;
break;
}

@@ -9817,20 +9812,8 @@ static struct notifier_block trace_die_notifier = {
void
trace_printk_seq(struct trace_seq *s)
{
- /* Probably should print a warning here. */
- if (s->seq.len >= TRACE_MAX_PRINT)
- s->seq.len = TRACE_MAX_PRINT;
-
- /*
- * More paranoid code. Although the buffer size is set to
- * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
- * an extra layer of protection.
- */
- if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
- s->seq.len = s->seq.size - 1;
-
/* should be zero ended, but we are paranoid. */
- s->buffer[s->seq.len] = 0;
+ printbuf_nul_terminate(&s->seq);

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

diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
index e34e8182ee..eabeeb97b5 100644
--- a/kernel/trace/trace_dynevent.c
+++ b/kernel/trace/trace_dynevent.c
@@ -295,21 +295,19 @@ int dynevent_arg_add(struct dynevent_cmd *cmd,
struct dynevent_arg *arg,
dynevent_check_arg_fn_t check_arg)
{
- int ret = 0;
-
if (check_arg) {
- ret = check_arg(arg);
+ int ret = check_arg(arg);
if (ret)
return ret;
}

- ret = seq_buf_printf(&cmd->seq, " %s%c", arg->str, arg->separator);
- if (ret) {
+ prt_printf(&cmd->seq, " %s%c", arg->str, arg->separator);
+ if (printbuf_overflowed(&cmd->seq)) {
pr_err("String is too long: %s%c\n", arg->str, arg->separator);
return -E2BIG;
}

- return ret;
+ return 0;
}

/**
@@ -340,25 +338,23 @@ int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
struct dynevent_arg_pair *arg_pair,
dynevent_check_arg_fn_t check_arg)
{
- int ret = 0;
-
if (check_arg) {
- ret = check_arg(arg_pair);
+ int ret = check_arg(arg_pair);
if (ret)
return ret;
}

- ret = seq_buf_printf(&cmd->seq, " %s%c%s%c", arg_pair->lhs,
- arg_pair->operator, arg_pair->rhs,
- arg_pair->separator);
- if (ret) {
+ prt_printf(&cmd->seq, " %s%c%s%c", arg_pair->lhs,
+ arg_pair->operator, arg_pair->rhs,
+ arg_pair->separator);
+ if (printbuf_overflowed(&cmd->seq)) {
pr_err("field string is too long: %s%c%s%c\n", arg_pair->lhs,
arg_pair->operator, arg_pair->rhs,
arg_pair->separator);
return -E2BIG;
}

- return ret;
+ return 0;
}

/**
@@ -373,15 +369,13 @@ int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
*/
int dynevent_str_add(struct dynevent_cmd *cmd, const char *str)
{
- int ret = 0;
-
- ret = seq_buf_puts(&cmd->seq, str);
- if (ret) {
+ prt_str(&cmd->seq, str);
+ if (printbuf_overflowed(&cmd->seq)) {
pr_err("String is too long: %s\n", str);
return -E2BIG;
}

- return ret;
+ return 0;
}

/**
@@ -410,7 +404,7 @@ void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
{
memset(cmd, '\0', sizeof(*cmd));

- seq_buf_init(&cmd->seq, buf, maxlen);
+ cmd->seq = PRINTBUF_EXTERN(buf, maxlen);
cmd->type = type;
cmd->run_command = run_command;
}
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index b458a9afa2..70cfd12410 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1059,7 +1059,7 @@ static void append_filter_err(struct trace_array *tr,
FILT_ERR_ERRNO, 0);
}
trace_seq_putc(s, 0);
- buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL);
+ buf = kstrdup(printbuf_str(&s->seq), GFP_KERNEL);
if (buf) {
kfree(filter->filter_string);
filter->filter_string = buf;
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 627e0e45f0..ddb2a2737b 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -1512,7 +1512,7 @@ static int synth_event_run_command(struct dynevent_cmd *cmd)
struct synth_event *se;
int ret;

- ret = create_or_delete_synth_event(cmd->seq.buffer);
+ ret = create_or_delete_synth_event(cmd->seq.buf);
if (ret)
return ret;

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 203204cadf..9f270fdde9 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1022,9 +1022,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
goto out;

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

trace_seq_puts(s, " */\n");
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 47cebef785..b97a912eed 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -915,7 +915,7 @@ static int create_or_delete_trace_kprobe(const char *raw_command)

static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
{
- return create_or_delete_trace_kprobe(cmd->seq.buffer);
+ return create_or_delete_trace_kprobe(printbuf_str(&cmd->seq));
}

/**
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 9c90b3a7dc..48c08f29c3 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -25,11 +25,9 @@
*/
#include <linux/uaccess.h>
#include <linux/seq_file.h>
+#include <linux/string.h>
#include <linux/trace_seq.h>

-/* How much buffer is left on the trace_seq? */
-#define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)
-
/*
* trace_seq should work with being initialized with 0s.
*/
@@ -54,7 +52,7 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)

__trace_seq_init(s);

- ret = seq_buf_print_seq(m, &s->seq);
+ ret = seq_write(m, s->seq.buf, printbuf_written(&s->seq));

/*
* Only reset this buffer if we successfully wrote to the
@@ -80,7 +78,7 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
*/
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
- unsigned int save_len = s->seq.len;
+ unsigned int save_pos = s->seq.pos;
va_list ap;

if (s->full)
@@ -89,12 +87,12 @@ void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
__trace_seq_init(s);

va_start(ap, fmt);
- seq_buf_vprintf(&s->seq, fmt, ap);
+ prt_vprintf(&s->seq, fmt, ap);
va_end(ap);

/* If we can't write it all, don't bother writing anything */
- if (unlikely(seq_buf_has_overflowed(&s->seq))) {
- s->seq.len = save_len;
+ if (unlikely(printbuf_overflowed(&s->seq))) {
+ s->seq.pos = save_pos;
s->full = 1;
}
}
@@ -111,17 +109,17 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
- unsigned int save_len = s->seq.len;
+ unsigned int save_pos = s->seq.pos;

if (s->full)
return;

__trace_seq_init(s);

- seq_buf_printf(&s->seq, "%*pb", nmaskbits, maskp);
+ prt_printf(&s->seq, "%*pb", nmaskbits, maskp);

- if (unlikely(seq_buf_has_overflowed(&s->seq))) {
- s->seq.len = save_len;
+ if (unlikely(printbuf_overflowed(&s->seq))) {
+ s->seq.pos = save_pos;
s->full = 1;
}
}
@@ -140,18 +138,18 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
*/
void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
- unsigned int save_len = s->seq.len;
+ unsigned int save_pos = s->seq.pos;

if (s->full)
return;

__trace_seq_init(s);

- seq_buf_vprintf(&s->seq, fmt, args);
+ prt_vprintf(&s->seq, fmt, args);

/* If we can't write it all, don't bother writing anything */
- if (unlikely(seq_buf_has_overflowed(&s->seq))) {
- s->seq.len = save_len;
+ if (unlikely(printbuf_overflowed(&s->seq))) {
+ s->seq.pos = save_pos;
s->full = 1;
}
}
@@ -174,18 +172,18 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
*/
void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
- unsigned int save_len = s->seq.len;
+ unsigned int save_pos = s->seq.pos;

if (s->full)
return;

__trace_seq_init(s);

- seq_buf_bprintf(&s->seq, fmt, binary);
+ prt_bstrprintf(&s->seq, fmt, binary);

/* If we can't write it all, don't bother writing anything */
- if (unlikely(seq_buf_has_overflowed(&s->seq))) {
- s->seq.len = save_len;
+ if (unlikely(!printbuf_overflowed(&s->seq))) {
+ s->seq.pos = save_pos;
s->full = 1;
return;
}
@@ -211,12 +209,12 @@ void trace_seq_puts(struct trace_seq *s, const char *str)

__trace_seq_init(s);

- if (len > TRACE_SEQ_BUF_LEFT(s)) {
+ if (len > printbuf_remaining(&s->seq)) {
s->full = 1;
return;
}

- seq_buf_putmem(&s->seq, str, len);
+ prt_bytes(&s->seq, str, len);
}
EXPORT_SYMBOL_GPL(trace_seq_puts);

@@ -237,12 +235,12 @@ void trace_seq_putc(struct trace_seq *s, unsigned char c)

__trace_seq_init(s);

- if (TRACE_SEQ_BUF_LEFT(s) < 1) {
+ if (!printbuf_remaining(&s->seq)) {
s->full = 1;
return;
}

- seq_buf_putc(&s->seq, c);
+ prt_char(&s->seq, c);
}
EXPORT_SYMBOL_GPL(trace_seq_putc);

@@ -263,12 +261,12 @@ void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)

__trace_seq_init(s);

- if (len > TRACE_SEQ_BUF_LEFT(s)) {
+ if (len > printbuf_remaining(&s->seq)) {
s->full = 1;
return;
}

- seq_buf_putmem(&s->seq, mem, len);
+ prt_bytes(&s->seq, mem, len);
}
EXPORT_SYMBOL_GPL(trace_seq_putmem);

@@ -285,24 +283,17 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
- unsigned int save_len = s->seq.len;
+ unsigned int save_pos = s->seq.pos;

if (s->full)
return;

__trace_seq_init(s);

- /* Each byte is represented by two chars */
- if (len * 2 > TRACE_SEQ_BUF_LEFT(s)) {
- s->full = 1;
- return;
- }
+ prt_hex_bytes(&s->seq, mem, len, 8, ' ');

- /* The added spaces can still cause an overflow */
- seq_buf_putmem_hex(&s->seq, mem, len);
-
- if (unlikely(seq_buf_has_overflowed(&s->seq))) {
- s->seq.len = save_len;
+ if (unlikely(printbuf_overflowed(&s->seq))) {
+ s->seq.pos = save_pos;
s->full = 1;
return;
}
@@ -323,22 +314,22 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
*/
int trace_seq_path(struct trace_seq *s, const struct path *path)
{
- unsigned int save_len = s->seq.len;
+ unsigned int save_pos = s->seq.pos;

if (s->full)
return 0;

__trace_seq_init(s);

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

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

- if (unlikely(seq_buf_has_overflowed(&s->seq))) {
- s->seq.len = save_len;
+ if (unlikely(printbuf_overflowed(&s->seq))) {
+ s->seq.pos = save_pos;
s->full = 1;
return 0;
}
@@ -369,8 +360,25 @@ EXPORT_SYMBOL_GPL(trace_seq_path);
*/
int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
{
+ int ret, len;
+
__trace_seq_init(s);
- return seq_buf_to_user(&s->seq, ubuf, cnt);
+
+ len = printbuf_written(&s->seq);
+ if (len <= s->readpos)
+ return -EBUSY;
+
+ 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;
}
EXPORT_SYMBOL_GPL(trace_seq_to_user);

@@ -378,24 +386,19 @@ 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;
+ unsigned int save_pos = s->seq.pos;

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);
+ prt_hex_dump(&s->seq, buf, len,
+ prefix_str, prefix_type,
+ rowsize, groupsize, ascii);

- if (unlikely(seq_buf_has_overflowed(&s->seq))) {
- s->seq.len = save_len;
+ if (unlikely(printbuf_overflowed(&s->seq))) {
+ s->seq.pos = save_pos;
s->full = 1;
return 0;
}
--
2.36.1
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