On Thu, Apr 21, 2011 at 04:20:36PM +0800, Bob Liu wrote: > > on mmu systems do_mmap_pgoff contains a len = PAGE_ALIGN(len); line. > > If we depend on this behavior, why not do it here as well and get rid > > of the #ifdef? > > > > If do it in do_mmap_pgoff() the whole system will be effected, I am > not sure whether > it's correct and needed for other subsystem. With "here" I was referring to uvc_queue_mmap. > >> + addr = (unsigned long)queue->mem + buffer->buf.m.offset; > >> + ret = addr; > > > > Why the intermediate step using addr? > > > > If don't return addr, do_mmap_pgoff() will return failure and we can't > setup vma correctly. > See mm/nommu.c line 1386(add = file->f_op->get_unmmapped_area() ). I know, but why not do ret = (unsigned long)queue->mem + buffer->buf.m.offset; instead? Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
