On Fri, Apr 25, 2025 at 04:41:22PM -0400, Steven Rostedt wrote: > From: Steven Rostedt <[email protected]> > > Getting the check if a task is a kernel thread or a user thread can be > error prone as it's not easy to see the difference. > > if (!(task->flags & PF_KTHREAD)) > > Is not immediately obvious that it's checking for a user thread. > > if (is_user_thread(task)) > > Is much easier to review, as it is obvious that it is checking if the task > is a user thread. > > Using a coccinelle script, convert these checks over to using either > is_user_thread() or is_kernel_thread(). > > $ cat kthread.cocci > @@ > identifier task; > @@ > - !(task->flags & PF_KTHREAD) > + is_user_thread(task) > @@ > identifier task; > @@ > - (task->flags & PF_KTHREAD) == 0 > + is_user_thread(task) > @@ > identifier task; > @@ > - (task->flags & PF_KTHREAD) != 0 > + is_kernel_thread(task) > @@ > identifier task; > @@ > - task->flags & PF_KTHREAD > + is_kernel_thread(task) > > $ spatch --dir --include-headers kthread.cocci . > /tmp/t.patch > $ patch -p1 < /tmp/t.patch > > Make sure to undo the conversion of the helper functions themselves! > > $ git show include/linux/sched.h | patch -p1 -R
FYI, the "file in" test can be helpful. I use it to exclude tools and samples regularly, and *I think* it would work for excluding individual files too: @name_of_rule depends !(file in "tools") && !(file in "samples")@ I've been collecting random notes like this here: https://github.com/kees/kernel-tools/tree/trunk/coccinelle > tools/sched_ext/scx_central.bpf.c | 2 +- > tools/sched_ext/scx_flatcg.bpf.c | 2 +- > tools/sched_ext/scx_qmap.bpf.c | 2 +- I think these are fine. The Makefile is pulling in standard kbuild Makefiles, so I think the correct include directories (outside of tools/) are being used. But yeah, easy mechanical change and a readability improvement. :) Reviewed-by: Kees Cook <[email protected]> -- Kees Cook
