[PATCH 3/5] IB/mthca: mthca_reg_user_mr(): use kmalloc() to allocate addresses array

[Mike Rapoport (Microsoft)]

mthca_reg_user_mr() allocates an array of DMA addresses during memory
registration.

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@xxxxxxxxxx
Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
---
 drivers/infiniband/hw/mthca/mthca_provider.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mthca/mthca_provider.c b/drivers/infiniband/hw/mthca/mthca_provider.c
index f90f67afc8fa..c9ec9ca0aaa6 100644
--- a/drivers/infiniband/hw/mthca/mthca_provider.c
+++ b/drivers/infiniband/hw/mthca/mthca_provider.c
@@ -895,7 +895,7 @@ static struct ib_mr *mthca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 		goto err_umem;
 	}
 
-	pages = (u64 *) __get_free_page(GFP_KERNEL);
+	pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!pages) {
 		err = -ENOMEM;
 		goto err_mtt;
@@ -924,7 +924,7 @@ static struct ib_mr *mthca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	if (i)
 		err = mthca_write_mtt(dev, mr->mtt, n, pages, i);
 mtt_done:
-	free_page((unsigned long) pages);
+	kfree(pages);
 	if (err)
 		goto err_mtt;
 

-- 
2.53.0