[PATCH 1/5] RDMA/umem: ib_umem_get(): use kmalloc() to allocate page array

["Mike Rapoport (Microsoft)" <rppt@kernel.org>]

ib_umem_get() allocates an array of pointers to struct page for
pin_user_pages_fast() calls during memory registration.

This array 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
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 drivers/infiniband/core/umem.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 73498723a5d5..5c42497f32e2 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -209,7 +209,7 @@ static struct ib_umem *__ib_umem_get_va(struct ib_device *device,
 
 	mmgrab(mm);
 
-	page_list = (struct page **) __get_free_page(GFP_KERNEL);
+	page_list = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!page_list) {
 		ret = -ENOMEM;
 		goto umem_kfree;
@@ -269,7 +269,7 @@ static struct ib_umem *__ib_umem_get_va(struct ib_device *device,
 	__ib_umem_release(device, umem, 0);
 	atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm);
 out:
-	free_page((unsigned long) page_list);
+	kfree(page_list);
 umem_kfree:
 	if (ret) {
 		mmdrop(umem->owning_mm);

-- 
2.53.0