From bdd6df6af98ce7e70702edfb5fd5dbbd8d1b0453 Mon Sep 17 00:00:00 2001 From: Eduard - Gabriel Munteanu Date: Mon, 23 Mar 2009 15:12:22 +0200 Subject: [PATCH] tracing: provide trace_seq_reserve() trace_seq_reserve() allows a caller to reserve space in a trace_seq and write directly into it. This makes it easier to export binary data to userspace via the tracing interface, by simply filling in a struct. Signed-off-by: Eduard - Gabriel Munteanu Signed-off-by: Ingo Molnar --- kernel/trace/trace_output.c | 13 +++++++++++++ kernel/trace/trace_output.h | 1 + 2 files changed, 14 insertions(+) diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 19261fdd245..6595074cbac 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -167,6 +167,19 @@ int trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len) return trace_seq_putmem(s, hex, j); } +void *trace_seq_reserve(struct trace_seq *s, size_t len) +{ + void *ret; + + if (len > ((PAGE_SIZE - 1) - s->len)) + return NULL; + + ret = s->buffer + s->len; + s->len += len; + + return ret; +} + int trace_seq_path(struct trace_seq *s, struct path *path) { unsigned char *p; diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index 35c422fb51a..0ae20b83eec 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -33,6 +33,7 @@ int trace_seq_puts(struct trace_seq *s, const char *str); int trace_seq_putc(struct trace_seq *s, unsigned char c); int trace_seq_putmem(struct trace_seq *s, void *mem, size_t len); int trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len); +void *trace_seq_reserve(struct trace_seq *s, size_t len); int trace_seq_path(struct trace_seq *s, struct path *path); int seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s, unsigned long sym_flags); -- 2.41.1