On Sun, Nov 20, 2011 at 09:56:32PM -0800, Ben Widawsky wrote: [snip the patch] > Bikeshed, but I would much prefer a #define for the swizzle > bit/cacheline size. I've looked at this stuff way too long, so I'm biased, but 64 = cacheline = dram fetch size = 1 << 64 feels about as natural for me as 4096 = PAGE_SIZE ... [snip the patch] > I must be missing something obvious here... > Can you explain how this can possibly be considered safe without holding > struct_mutex? That's the reason why the commit msg goes through every case and explains why I think it's safe. The large thing here is that we need to drop the mutex when calling copy_*_user (at least in the non-atomic slow-paths) because otherwise we might deadlock with our own pagefault handler. -Daniel -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
