On Mon, 2023-07-17 at 11:04 -0700, Paul E. McKenney wrote:
> RCU Tasks Trace is quite specialized, having been created specifically
> for sleepable BPF programs. Because it allows general blocking within
> readers, any new use of RCU Tasks Trace must take current use cases into
> account. Therefore, update checkpatch.pl to complain about use of any of
> the RCU Tasks Trace API members outside of BPF and outside of RCU itself.
>
> Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx> (maintainer:CHECKPATCH)
> Cc: Joe Perches <joe@xxxxxxxxxxx> (maintainer:CHECKPATCH)
> Cc: Dwaipayan Ray <dwaipayanray1@xxxxxxxxx> (reviewer:CHECKPATCH)
> Cc: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
> Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> Cc: <bpf@xxxxxxxxxxxxxxx>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> ---
> scripts/checkpatch.pl | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -7457,6 +7457,24 @@ sub process {
> }
> }
>
> +# Complain about RCU Tasks Trace used outside of BPF (and of course, RCU).
> + if ($line =~ /\brcu_read_lock_trace\s*\(/ ||
> + $line =~ /\brcu_read_lock_trace_held\s*\(/ ||
> + $line =~ /\brcu_read_unlock_trace\s*\(/ ||
> + $line =~ /\bcall_rcu_tasks_trace\s*\(/ ||
> + $line =~ /\bsynchronize_rcu_tasks_trace\s*\(/ ||
> + $line =~ /\brcu_barrier_tasks_trace\s*\(/ ||
> + $line =~ /\brcu_request_urgent_qs_task\s*\(/) {
> + if ($realfile !~ m@^kernel/bpf@ &&
> + $realfile !~ m@^include/linux/bpf@ &&
> + $realfile !~ m@^net/bpf@ &&
> + $realfile !~ m@^kernel/rcu@ &&
> + $realfile !~ m@^include/linux/rcu@) {
Functions and paths like these tend to be accreted.
Please use a variable or 2 like:
our $rcu_trace_funcs = qr{(?x:
rcu_read_lock_trace |
rcu_read_lock_trace_held |
rcu_read_unlock_trace |
call_rcu_tasks_trace |
synchronize_rcu_tasks_trace |
rcu_barrier_tasks_trace |
rcu_request_urgent_qs_task
)};
our $rcu_trace_paths = qr{(?x:
kernel/bfp/ |
include/linux/bpf |
net/bpf/ |
kernel/rcu/ |
include/linux/rcu
)};
...
if ($line =~ /\b($rcu_trace_funcs)\s*\(/ &&
$realfile !~ m{^$rcu_trace_paths}) {
WARN("RCU_TASKS_TRACE",
"use of RCU tasks trace '$1' is incorrect outside BPF or core RCU code\n" . $herecurr); }
}
