On Tue, Dec 28, 2010 at 2:37 PM, Ohad Ben-Cohen <ohad@xxxxxxxxxx> wrote: > On Tue, Dec 28, 2010 at 2:24 PM, Felipe Contreras > <felipe.contreras@xxxxxxxxx> wrote: >> user-space crashed, not kernel-space; the code would continue to run >> and eventually release the lock. > > So you'll have to be more specific about the scenario you are describing. > > If there's a user thread that is still running the proc_*_dma() > function, and we agree that this thread keeps running until completion > and then returns to user space, what's the problem ? The problem is if the user-space process crashes exactly in the middle of it, *before* completing. With locks there's no problem, as proc_un_map() would wait for the lock in my patch. In your patch it would not wait, just return -EBUSY. > If that user thread will crash, drv_remove_all_resources() will clean > up all map_obj's. Not if a proc_*_dma() is still running. There's a very narrow timing window where this could happen, but it is there. -- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
