[PATCH 05/14] s390/sclp_con: Replace get_zeroed_page() with kzalloc()

[Mike Rapoport (Microsoft)]

sclp_console_init() allocates the SCCBs that are used as the output
buffers of the SCLP line mode console.

These buffers can be allocated with kmalloc() as there's nothing special
about them 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_zeroed_page() with kzalloc() 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/s390/char/sclp_con.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c
index d8544c485808e..9d096d7b59687 100644
--- a/drivers/s390/char/sclp_con.c
+++ b/drivers/s390/char/sclp_con.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/kmod.h>
+#include <linux/slab.h>
 #include <linux/console.h>
 #include <linux/init.h>
 #include <linux/panic_notifier.h>
@@ -272,7 +273,7 @@ static void __init __sclp_console_free_pages(void)
 
 	list_for_each_safe(page, p, &sclp_con_pages) {
 		list_del(page);
-		free_page((unsigned long)page);
+		kfree(page);
 	}
 }
 
@@ -294,7 +295,7 @@ sclp_console_init(void)
 		return rc;
 	/* Allocate pages for output buffering */
 	for (i = 0; i < sclp_console_pages; i++) {
-		page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
+		page = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA);
 		if (!page) {
 			__sclp_console_free_pages();
 			return -ENOMEM;

-- 
2.53.0