diff options
| -rw-r--r-- | include/linux/ftrace_event.h | 1 | ||||
| -rw-r--r-- | include/linux/trace_seq.h | 5 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 35 | ||||
| -rw-r--r-- | kernel/trace/trace_output.c | 14 |
4 files changed, 47 insertions, 8 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 47bbdf9c38d..38f8d655383 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -57,6 +57,7 @@ struct trace_iterator { /* The below is zeroed out in pipe_read */ struct trace_seq seq; struct trace_entry *ent; + int leftover; int cpu; u64 ts; diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 09077f6ed12..fad6857bc0f 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -33,7 +33,7 @@ extern int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) __attribute__ ((format (printf, 2, 0))); extern int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary); -extern void trace_print_seq(struct seq_file *m, struct trace_seq *s); +extern int trace_print_seq(struct seq_file *m, struct trace_seq *s); extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt); extern int trace_seq_puts(struct trace_seq *s, const char *str); @@ -55,8 +55,9 @@ trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) return 0; } -static inline void trace_print_seq(struct seq_file *m, struct trace_seq *s) +static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s) { + return 0; } static inline ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index dc937e1baa9..484114d7074 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1516,6 +1516,8 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos) int i = (int)*pos; void *ent; + WARN_ON_ONCE(iter->leftover); + (*pos)++; /* can't go backwards */ @@ -1614,8 +1616,16 @@ static void *s_start(struct seq_file *m, loff_t *pos) ; } else { - l = *pos - 1; - p = s_next(m, p, &l); + /* + * If we overflowed the seq_file before, then we want + * to just reuse the trace_seq buffer again. + */ + if (iter->leftover) + p = iter; + else { + l = *pos - 1; + p = s_next(m, p, &l); + } } trace_event_read_lock(); @@ -1923,6 +1933,7 @@ static enum print_line_t print_trace_line(struct trace_iterator *iter) static int s_show(struct seq_file *m, void *v) { struct trace_iterator *iter = v; + int ret; if (iter->ent == NULL) { if (iter->tr) { @@ -1942,9 +1953,27 @@ static int s_show(struct seq_file *m, void *v) if (!(trace_flags & TRACE_ITER_VERBOSE)) print_func_help_header(m); } + } else if (iter->leftover) { + /* + * If we filled the seq_file buffer earlier, we + * want to just show it now. + */ + ret = trace_print_seq(m, &iter->seq); + + /* ret should this time be zero, but you never know */ + iter->leftover = ret; + } else { print_trace_line(iter); - trace_print_seq(m, &iter->seq); + ret = trace_print_seq(m, &iter->seq); + /* + * If we overflow the seq_file buffer, then it will + * ask us for this data again at start up. + * Use that instead. + * ret is 0 if seq_file write succeeded. + * -1 otherwise. + */ + iter->leftover = ret; } return 0; diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index b6c12c6a1bc..e5cf90fef34 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -23,13 +23,21 @@ static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly; static int next_event_type = __TRACE_LAST_TYPE + 1; -void trace_print_seq(struct seq_file *m, struct trace_seq *s) +int trace_print_seq(struct seq_file *m, struct trace_seq *s) { int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; + int ret; + + ret = seq_write(m, s->buffer, len); - seq_write(m, s->buffer, len); + /* + * Only reset this buffer if we successfully wrote to the + * seq_file buffer. + */ + if (!ret) + trace_seq_init(s); - trace_seq_init(s); + return ret; } enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter) |