[PATCH v2 22/27] function_graph: Use for_each_set_bit() in __ftrace_return_to_handler()

From: Steven Rostedt
Date: Sat Jun 01 2024 - 23:41:59 EST


From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>

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.

Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
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