On Wed, Dec 29, 2010 at 11:39 AM, Felipe Contreras <felipe.contreras@xxxxxxxxx> wrote: > 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. We have two threads. One called proc_un_map(), and one called proc_begin_dma(). The first crashed, but the second didn't. it still holds the bridge device open. When it will exit, and release the device, then drv_remove_all_resources() will be called, and all the map_obj's will be cleaned. > >> 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. It will be called after it will return, and its thread will exit (or crash). -- 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
