Commit bdd6df6a authored by Eduard - Gabriel Munteanu's avatar Eduard - Gabriel Munteanu Committed by Ingo Molnar
Browse files

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: default avatarEduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 2a4efa42

kernel/trace/trace_output.c

+13 −0
Original line number Diff line number Diff line
@@ -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;

kernel/trace/trace_output.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

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