On Wed, Dec 29, 2010 at 11:46 AM, Ohad Ben-Cohen <ohad@xxxxxxxxxx> wrote: > 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. I'm not familiar how crashes are handled; if you say as long as one task is still running the device release is not called, then I guess there's no issue. -- 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
