Commit 75d7ff9a authored by Vincent Donnefort's avatar Vincent Donnefort Committed by Steven Rostedt (Google)
Browse files

selftests/ring-buffer: Handle meta-page bigger than the system 

Handle the case where the meta-page content is bigger than the system
page-size. This prepares the ground for extending features covered by
the meta-page.

Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-kselftest@vger.kernel.org
Link: https://lore.kernel.org/20240910162335.2993310-3-vdonnefort@google.com


Acked-by: default avatarShuah Khan <skhan@linuxfoundation.org>
Signed-off-by: default avatarVincent Donnefort <vdonnefort@google.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 21ff365b

tools/testing/selftests/ring-buffer/map_test.c

+10 −0
Original line number Diff line number Diff line
@@ -92,12 +92,22 @@ int tracefs_cpu_map(struct tracefs_cpu_map_desc *desc, int cpu) 
	if (desc->cpu_fd < 0)

		return -ENODEV;



again:

	map = mmap(NULL, page_size, PROT_READ, MAP_SHARED, desc->cpu_fd, 0);

	if (map == MAP_FAILED)

		return -errno;



	desc->meta = (struct trace_buffer_meta *)map;



	/* the meta-page is bigger than the original mapping */

	if (page_size < desc->meta->meta_struct_len) {

		int meta_page_size = desc->meta->meta_page_size;



		munmap(desc->meta, page_size);

		page_size = meta_page_size;

		goto again;

	}



	return 0;

}