Re: [RFC PATCH v2 5/5] btrfs: implement RWF_ENCODED writes

On Mon, Oct 21, 2019 at 03:14:52PM +0200, David Sterba wrote:

On Fri, Oct 18, 2019 at 03:55:13PM -0700, Omar Sandoval wrote:

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+	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.

Good to know, I'll fix both places I'm doing this, then.