tty: hvcs: replace __get_free_page() with kmalloc()

hvcs_initialize() allocates the buffer that receives the partner info
returned by the H_VTERM_PARTNER_INFO hypercall. The buffer is passed to
the hypervisor as a physical address and it must not cross a page
boundary.

kmalloc() guarantees that a power of two sized allocation is aligned to
its size, so a PAGE_SIZE allocation is page aligned as well.

This buffer can be allocated with kmalloc() as there's nothing special
about it to go directly to the page allocator.

kmalloc() provides a better API that does not require ugly casts and
kfree() does not need to know the size of the freed object.

Performance difference between kmalloc() and __get_free_pages() is not
measurable as both allocators take an object/page from a per-CPU list for
fast path allocations.

For the slow path the performance is anyway determined by the amount of
reclaim involved rather than by what allocator is used.

Replace use of __get_free_page() with kmalloc() and free_page() with
kfree().

Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com
Assisted-by: copilot:claude-opus
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260831-tty-v2-3-88cd58c3c640@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions