Re: [PATCH v2] t10-pi: reduce ref tag code duplication

[Christoph Hellwig]

On Thu, Apr 16, 2026 at 08:38:07AM -0700, Caleb Sander Mateos wrote:
> On Wed, Apr 15, 2026 at 10:18 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> >
> > On Wed, Apr 15, 2026 at 03:08:47PM -0600, Caleb Sander Mateos wrote:
> > >  #ifndef _LINUX_T10_PI_H
> > >  #define _LINUX_T10_PI_H
> > >
> > >  #include <linux/types.h>
> > >  #include <linux/blk-mq.h>
> > > +#include <linux/wordpart.h>
> >
> > We must have already gotten this implicitly given that the code
> > already uses lower_48_bits.
> 
> lower_48_bits() is defined (and only used) in this header. Yes,
> wordpart.h is already transitively included by the other headers, but
> I think it's good practice for each file to explicitly include the
> headers defining all the items it uses. It reduces the risk that
> refactoring the other header files in the future will result in a
> compilation error here by dropping the transitive include.

In general pulling in a new header when no new user of it shows up is a
bit weird.  I don't want to hold the patch up on this, but there are
folks out there actually dropping not needed includes from headers as
it can significantly reduce compile time.  Now this is not a heavily
included header so it's unlikely to make a difference anyway.