Messages in this thread | | | Subject | Re: [PATCH 01/18] lirc core device driver infrastructure | From | Andi Kleen <> | Date | Tue, 09 Sep 2008 11:46:48 +0200 |
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Jarod Wilson <jwilson@redhat.com> writes:
Just some quick comments, no complete review
> +EXTRA_CFLAGS =-DIRCTL_DEV_MAJOR=61 -DLIRC_SERIAL_TRANSMITTER -I$(src)
Put the Ds into some include instead?
> + > +static int debug; > +#define dprintk(fmt, args...) \ > + do { \ > + if (debug) \ > + printk(KERN_DEBUG fmt, ## args); \ > + } while (0)
There's some effort to replace that all with pr_printk
> + dprintk(LOGHEAD "poll thread started\n", ir->p.name, ir->p.minor); > + > + do { > + if (ir->open) { > + if (ir->jiffies_to_wait) { > + set_current_state(TASK_INTERRUPTIBLE); > + schedule_timeout(ir->jiffies_to_wait); > + } else { > + interruptible_sleep_on( > + ir->p.get_queue(ir->p.data));
sleep_on is really discouraged, consider replacing it with wait_event()
> + } > + if (kthread_should_stop()) > + break; > + if (!add_to_buf(ir)) > + wake_up_interruptible(&ir->buf->wait_poll); > + } else { > + /* if device not opened so we can sleep half a second */ > + set_current_state(TASK_INTERRUPTIBLE); > + schedule_timeout(HZ/2);
This means you always wake up every half a second? That will not make the powertop users happy. When there's nothing to do it should just sleep.
The checks in plugin_register seem a bit extreme. At least make that all WARN_ONs
> + > + /* end up polling thread */ > + if (ir->task) { > + wake_up_process(ir->task); > + kthread_stop(ir->task); > + } > + > + dprintk("lirc_dev: plugin %s unregistered from minor number = %d\n", > + ir->p.name, ir->p.minor); > + > + ir->attached = 0; > + if (ir->open) { > + dprintk(LOGHEAD "releasing opened plugin\n", > + ir->p.name, ir->p.minor); > + wake_up_interruptible(&ir->buf->wait_poll);
This seems racy with some users who are lockless
> + mutex_lock(&ir->buffer_lock); > + ir->p.set_use_dec(ir->p.data); > + module_put(ir->p.owner); > + mutex_unlock(&ir->buffer_lock); > + } else > + cleanup(ir); > + mutex_unlock(&plugin_lock); > + > +/* > + * Recent kernels should handle this autmatically by increasing/decreasing > + * use count when a dependant module is loaded/unloaded. > + */
All kernels are recent now.
> +#ifdef MODULE > + > +/* > + * > + */ > +int init_module(void) > +{ > + return lirc_dev_init(); > +} > + > +/* > + * > + */ > +void cleanup_module(void) > +{ > + /* unregister_chrdev returns void now */ > + unregister_chrdev(IRCTL_DEV_MAJOR, IRCTL_DEV_NAME); > + class_destroy(lirc_class); > + dprintk("lirc_dev: module unloaded\n"); > +} > + > +MODULE_DESCRIPTION("LIRC base driver module"); > +MODULE_AUTHOR("Artur Lipowski"); > +MODULE_LICENSE("GPL"); > +MODULE_ALIAS_CHARDEV_MAJOR(IRCTL_DEV_MAJOR); > + > +module_param(debug, bool, 0644); > +MODULE_PARM_DESC(debug, "Enable debugging messages"); > + > +#else /* not a MODULE */ > +subsys_initcall(lirc_dev_init); > + > +#endif /* MODULE */
Always use the #ifdef MODULE path, it does DTRT when compiled in too. Remove the init_module wrapper, replace with module_init()
... not read further ... -Andi
-- ak@linux.intel.com
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