[PATCH 1/2] usb: host: ohci-dbg: use kmalloc() for print buffer

[Mike Rapoport (Microsoft)]

ochi-dbg allocates buffers for formatting of various dump outputs.

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().

While on it, make kfree() calls unconditional since kfree() can be passed a
NULL pointer.

Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@xxxxxxxxxx
Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
---
 drivers/usb/host/ohci-dbg.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/host/ohci-dbg.c b/drivers/usb/host/ohci-dbg.c
index 9e0e06bbc570..0a648a7d9136 100644
--- a/drivers/usb/host/ohci-dbg.c
+++ b/drivers/usb/host/ohci-dbg.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-1.0+
+#include <linux/slab.h>
 /*
  * OHCI HCD (Host Controller Driver) for USB.
  *
@@ -683,7 +684,7 @@ static int fill_buffer(struct debug_buffer *buf)
 	int ret;
 
 	if (!buf->page)
-		buf->page = (char *)get_zeroed_page(GFP_KERNEL);
+		buf->page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 
 	if (!buf->page) {
 		ret = -ENOMEM;
@@ -729,11 +730,8 @@ static int debug_close(struct inode *inode, struct file *file)
 {
 	struct debug_buffer *buf = file->private_data;
 
-	if (buf) {
-		if (buf->page)
-			free_page((unsigned long)buf->page);
-		kfree(buf);
-	}
+	kfree(buf->page);
+	kfree(buf);
 
 	return 0;
 }
@@ -782,4 +780,3 @@ static inline void remove_debug_files (struct ohci_hcd *ohci)
 }
 
 /*-------------------------------------------------------------------------*/
-

-- 
2.53.0