[PATCH bpf 1/2] bpf: Clarify a bpf_bprintf_prepare macro

From: Florent Revest
Date: Mon May 17 2021 - 05:28:54 EST


The per-cpu buffers contain bprintf data rather than printf arguments.
The macro name and comment were a bit confusing, this rewords them in a
clearer way.

Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
---
kernel/bpf/helpers.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index ef658a9ea5c9..3a5ab614cbb0 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -692,13 +692,14 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
return -EINVAL;
}

-/* Per-cpu temp buffers which can be used by printf-like helpers for %s or %p
+/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
+ * arguments representation.
*/
-#define MAX_PRINTF_BUF_LEN 512
+#define MAX_BPRINTF_BUF_LEN 512

/* Support executing three nested bprintf helper calls on a given CPU */
struct bpf_bprintf_buffers {
- char tmp_bufs[3][MAX_PRINTF_BUF_LEN];
+ char tmp_bufs[3][MAX_BPRINTF_BUF_LEN];
};
static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
@@ -761,7 +762,7 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
return -EBUSY;

- tmp_buf_end = tmp_buf + MAX_PRINTF_BUF_LEN;
+ tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
*bin_args = (u32 *)tmp_buf;
}

--
2.31.1.751.gd2f1c929bd-goog