Re: [PATCH v2 0/4] scsi: replace __get_free_pages() with kmalloc()

[Mike Rapoport <rppt@kernel.org>]

Gentle ping.

On Sat, Jul 04, 2026 at 09:13:33AM +0300, Mike Rapoport (Microsoft) wrote:
> This is a (small) part of larger work of replacing page allocator calls
> with kmalloc.
> 
> My initial intention a few month ago was to remove ugly casts [1], but then
> willy pointed out that Linus objected to something like this [2] and it
> looks like more than a decade old technical debt.
> 
> Largely, anything that doesn't need struct page (or a memdesc in the
> future) should just use kmalloc() or kvmalloc() to allocate memory.
> kmalloc() guarantees alignment, physical contiguity and working
> virt_to_phys() and beside nicer API that returns void * on alloc and
> doesn't require to know the allocation size on free, kmalloc() provides
> better debugging capabilities than page allocator.
> 
> Another thing is that touching these allocation sites gives the reviewers
> opportunity to see if a PAGE_SIZE buffer is actually needed or maybe
> another size is appropriate.
> 
> For larger allocations that don't need physically contiguous memory
> kvmalloc() can be a better option that __get_free_pages() because under
> memory pressure it's is easier to allocate several order-0 pages than a
> physically contiguous chunk with the same number of pages.
> 
> And last, but not least, removing needless calls to page allocator should
> help with memdesc (aka project folio) conversion. There will be way less
> places to audit to see if the user was actually using struct page.
> 
> Also in git:
> https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git gfp-to-kmalloc/scsi
> 
> [1] https://lore.kernel.org/all/20251018093002.3660549-1-rppt@kernel.org/
> [2] https://lore.kernel.org/all/CA+55aFwp4iy4rtX2gE2WjBGFL=NxMVnoFeHqYa2j1dYOMMGqxg@mail.gmail.com/ 
> 
> ---
> v2 changes:
> * replace GFP_ATOMIC with GFP_NOIO in ipr driver
> 
> v1: https://patch.msgid.link/20260630-b4-scsi-v1-0-494fb37ebe7b@kernel.org
> 
> ---
> Mike Rapoport (Microsoft) (4):
>       scsi: target: file: use kmalloc() to allocate temporary protection buffer
>       scsi: proc: use kmalloc() in proc writers
>       scsi: ipr: use kmalloc() to allocate IPR dump buffer memory
>       scsi: sym53c8xx_2: replace __get_free_pages() with kmalloc()
> 
>  drivers/scsi/ipr.c                  | 4 ++--
>  drivers/scsi/scsi_devinfo.c         | 5 +++--
>  drivers/scsi/scsi_proc.c            | 9 +++++----
>  drivers/scsi/sym53c8xx_2/sym_hipd.h | 4 ++--
>  drivers/target/target_core_file.c   | 4 ++--
>  5 files changed, 14 insertions(+), 12 deletions(-)
> ---
> base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
> change-id: 20260611-b4-scsi-d0b0eb4895f4
> 
> --
> Sincerely yours,
> Mike.
> 

-- 
Sincerely yours,
Mike.