Re: [PATCH 0/6] s390/drivers: replace __get_free_pages() call with kmalloc()

[Mike Rapoport <rppt@kernel.org>]

On Thu, May 28, 2026 at 04:48:41PM +0200, Alexander Gordeev wrote:
> On Thu, May 28, 2026 at 10:09:48AM +0300, Mike Rapoport (Microsoft) wrote:
> 
> Hi Mike,
> 
> > This is a (tiny) part of larger work of replacing page allocator calls
> > with kmalloc.
> > 
> > Nowadays the right way to say "I need a buffer" is kmalloc() rather than
> > ancient and ugly __get_free_pages().
> > 
> > Also in git:
> > https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git gfp-to-kmalloc/s390-drivers
> > 
> > ---
> > Mike Rapoport (Microsoft) (6):
> >       s390/con3270: replace __get_free_page() with kmalloc()
> >       s390/dasd: replace get_zeroed_page() with kzalloc()
> >       s390/hvc_iucv: replace get_zeroed_page() with kzalloc()
> >       s390/qeth: replace get_zeroed_page() with kzalloc()
> >       s390/trng: replace __get_free_page() with kmalloc()
> >       s390/zcrypt: replace get_zeroed_page() with kzalloc()
> > 
> >  drivers/char/hw_random/s390-trng.c |  5 +++--
> >  drivers/s390/block/dasd_eckd.c     | 12 ++++++------
> >  drivers/s390/block/dasd_eer.c      |  4 ++--
> >  drivers/s390/char/con3270.c        |  8 ++++----
> >  drivers/s390/crypto/zcrypt_api.c   |  6 +++---
> >  drivers/s390/net/qeth_core_main.c  |  4 ++--
> >  drivers/tty/hvc/hvc_iucv.c         |  6 +++---
> >  7 files changed, 23 insertions(+), 22 deletions(-)
> 
> Did you use a particular tool/script to identify these locations?
> The immediat question would by why these sources only and not the
> others that also use the old functions?

I used an LLM to identify "the most safe callers to convert" to being with. 

Since every call site requires a manual review of the surrounding code and
the actual usage, for the first round I limited the changes to allocations
that are temporary or staging buffers.

With a less restrictive prompt I've got 57 patches to s390 (both arch/ and
drivers/), bu that's too much for me to chew in a single setting :)

If you are curious, overall changes (before the human review) are here:
https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=gfp-to-kmalloc/v0.2
 
> Thanks!

-- 
Sincerely yours,
Mike.