On Fri, Oct 18, 2019 at 03:55:13PM -0700, Omar Sandoval wrote: > > > + nr_pages = (disk_num_bytes + PAGE_SIZE - 1) >> PAGE_SHIFT; > > > > nit: nr_pages = DIV_ROUND_UP(disk_num_bytes, PAGE_SIZE) > > disk_num_bytes is a u64, so that would expand to a 64-bit division. The > compiler is probably smart enough to optimize it to a shift, but I > didn't want to rely on that, because that would cause build failures on > 32-bit. There are several DIV_ROUND_UP(u64, PAGE_SIZE) in btrfs code, no build brekages have been reported so far, you can use it.