[for-next,22/27] function_graph: Use for_each_set_bit() in __ftrace_return_to_handler()

Commit Message

Steven Rostedt June 4, 2024, 2:41 p.m. UTC

From: "Steven Rostedt (Google)" <[e-mail]>

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/[e-mail]

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

Patch

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;