Evgeniy Polyakov <[EMAIL PROTECTED]> wrote: > > I'm pleased to annouce CBUS - ultra fast (for insert operations) > message bus.
> +static int cbus_enqueue(struct cbus_event_container *c, struct cn_msg *msg) > +{ > + int err; > + struct cbus_event *event; > + unsigned long flags; > + > + event = kmalloc(sizeof(*event) + msg->len, GFP_ATOMIC); Using GFP_ATOMIC is a bit lame. It would be better to require the caller to pass in the gfp_flags. Or simply require that all callers not hold locks and use GFP_KERNEL. > +static int cbus_process(struct cbus_event_container *c, int all) > +{ > + struct cbus_event *event; > + int len, i, num; > + > + if (list_empty(&c->event_list)) > + return 0; > + > + if (all) > + len = c->qlen; > + else > + len = 1; > + > + num = 0; > + for (i=0; i<len; ++i) { > + event = cbus_dequeue(c); > + if (!event) > + continue; > + > + cn_netlink_send(&event->msg, 0); > + num++; > + > + kfree(event); > + } > + > + return num; > +} It might be cleaner to pass in an item count rather than a boolean `all' here. Then again, it seems racy. The initial list_empty() call could fail to detect new events due to lack of locking and memory barriers. We conventionally code for loops as for (i = 0; i < len; i++) > +static int cbus_event_thread(void *data) > +{ > + int i, non_empty = 0, empty = 0; > + struct cbus_event_container *c; > + > + daemonize(cbus_name); > + allow_signal(SIGTERM); > + set_user_nice(current, 19); Please use the kthread api for managing this thread. Is a new kernel thread needed? > + while (!cbus_need_exit) { > + if (empty || non_empty == 0 || non_empty > 10) { > + interruptible_sleep_on_timeout(&cbus_wait_queue, 10); interruptible_sleep_on_timeout() is heavily deprecated and is racy without external locking (it pretty much has to be the BKL). Use wait_event_timeout(). > +int __devinit cbus_init(void) > +{ > + int i, err = 0; > + struct cbus_event_container *c; > + > + for_each_cpu(i) { > + c = &per_cpu(cbus_event_list, i); > + cbus_init_event_container(c); > + } > + > + init_completion(&cbus_thread_exited); > + > + cbus_pid = kernel_thread(cbus_event_thread, NULL, CLONE_FS | > CLONE_FILES); Using the kthread API would clean this up. > + if (IS_ERR((void *)cbus_pid)) { The weird cast here might not even work at all on 64-bit architectures. It depends if they sign extend ints when casting them to pointers. I guess they do. If cbus_pid is indeed an s32. Much better to do if (cbus_pid < 0) > +void __devexit cbus_fini(void) > +{ > + int i; > + struct cbus_event_container *c; > + > + cbus_need_exit = 1; > + kill_proc(cbus_pid, SIGTERM, 0); > + wait_for_completion(&cbus_thread_exited); > + > + for_each_cpu(i) { > + c = &per_cpu(cbus_event_list, i); > + cbus_fini_event_container(c); > + } > +} I think this is racy. What stops new events from being queued while this function is in progress? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/