2024-06-04 15:18:12

by Steven Rostedt

[permalink] [raw]
Subject: [for-next][PATCH 22/27] function_graph: Use for_each_set_bit() in __ftrace_return_to_handler()

From: "Steven Rostedt (Google)" <[email protected]>

Instead of iterating through the entire fgraph_array[] and seeing if one
of the bitmap bits are set to know to call the array's retfunc() function,
use for_each_set_bit() on the bitmap itself. This will only iterate for
the number of set bits.

Link: https://lore.kernel.org/linux-trace-kernel/[email protected]

Cc: Mark Rutland <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Florent Revest <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: bpf <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Alan Maguire <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Guo Ren <[email protected]>
Reviewed-by: Masami Hiramatsu (Google) <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
---
kernel/trace/fgraph.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index f207b7ae5f46..0827b67f746d 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -783,11 +783,10 @@ static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs
#endif

bitmap = get_bitmap_bits(current, offset);
- for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) {
+
+ for_each_set_bit(i, &bitmap, sizeof(bitmap) * BITS_PER_BYTE) {
struct fgraph_ops *gops = fgraph_array[i];

- if (!(bitmap & BIT(i)))
- continue;
if (gops == &fgraph_stub)
continue;

--
2.43.0