On Wed, 2009-02-25 at 00:15 -0800, Eric Anholt wrote: > > Or you could get_user_pages() to fault the user pages and pin them, and > > then do pagefault_disable() and use copy_from_user_inatomic or such, and > > release the pages again. > > I started poking at this today, since the get_user_pages sounded like > the solution. Only then I noticed: when we unbind an existing object, > we have to unmap_mapping_range to clear the clients' mappings to it in > the GTT, which needs to happen while the struct lock (protecting the gtt > structure and the gtt to object mappings) is held. So for fault we have > mmap_sem held to struct mutex taken for poking at the gtt structure, and > for unbind we have struct mutex held to mmap_sem taken to clear > mappings.
So it again comes down to the fact that you cannot pin a gtt object without also holding this struct_mutex? Normally such things are done by elevating a refcount so that both regular frees and reclaim gets delayed until you're done with the object. ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
