[PATCH net-next 5/8] mwifiex: debugfs: use kzalloc() to allocate formatting buffers

[Mike Rapoport (Microsoft)]

mwifiex debugfs functions allocate buffers for formatting debug output
text using get_zeroed_page().

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/net/wireless/marvell/mwifiex/debugfs.c | 62 +++++++++++---------------
 1 file changed, 27 insertions(+), 35 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/debugfs.c b/drivers/net/wireless/marvell/mwifiex/debugfs.c
index 9deaf59dcb62..573768b6ad91 100644
--- a/drivers/net/wireless/marvell/mwifiex/debugfs.c
+++ b/drivers/net/wireless/marvell/mwifiex/debugfs.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/debugfs.h>
+#include <linux/slab.h>
 
 #include "main.h"
 #include "11n.h"
@@ -67,8 +68,8 @@ mwifiex_info_read(struct file *file, char __user *ubuf,
 	struct net_device *netdev = priv->netdev;
 	struct netdev_hw_addr *ha;
 	struct netdev_queue *txq;
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
-	char *p = (char *) page, fmt[64];
+	char *page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	char *p = page, fmt[64];
 	struct mwifiex_bss_info info;
 	ssize_t ret;
 	int i = 0;
@@ -133,11 +134,10 @@ mwifiex_info_read(struct file *file, char __user *ubuf,
 	}
 	p += sprintf(p, "\n");
 
-	ret = simple_read_from_buffer(ubuf, count, ppos, (char *) page,
-				      (unsigned long) p - page);
+	ret = simple_read_from_buffer(ubuf, count, ppos, page, p - page);
 
 free_and_exit:
-	free_page(page);
+	kfree(page);
 	return ret;
 }
 
@@ -168,8 +168,8 @@ mwifiex_getlog_read(struct file *file, char __user *ubuf,
 {
 	struct mwifiex_private *priv =
 		(struct mwifiex_private *) file->private_data;
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
-	char *p = (char *) page;
+	char *page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	char *p = page;
 	ssize_t ret;
 	struct mwifiex_ds_get_stats stats;
 
@@ -220,11 +220,10 @@ mwifiex_getlog_read(struct file *file, char __user *ubuf,
 		     stats.bcn_miss_cnt);
 
 
-	ret = simple_read_from_buffer(ubuf, count, ppos, (char *) page,
-				      (unsigned long) p - page);
+	ret = simple_read_from_buffer(ubuf, count, ppos, page, p - page);
 
 free_and_exit:
-	free_page(page);
+	kfree(page);
 	return ret;
 }
 
@@ -247,8 +246,8 @@ mwifiex_histogram_read(struct file *file, char __user *ubuf,
 	ssize_t ret;
 	struct mwifiex_histogram_data *phist_data;
 	int i, value;
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
-	char *p = (char *)page;
+	char *page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	char *p = page;
 
 	if (!p)
 		return -ENOMEM;
@@ -309,11 +308,10 @@ mwifiex_histogram_read(struct file *file, char __user *ubuf,
 				i, value);
 	}
 
-	ret = simple_read_from_buffer(ubuf, count, ppos, (char *)page,
-				      (unsigned long)p - page);
+	ret = simple_read_from_buffer(ubuf, count, ppos, page, p - page);
 
 free_and_exit:
-	free_page(page);
+	kfree(page);
 	return ret;
 }
 
@@ -383,8 +381,8 @@ mwifiex_debug_read(struct file *file, char __user *ubuf,
 {
 	struct mwifiex_private *priv =
 		(struct mwifiex_private *) file->private_data;
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
-	char *p = (char *) page;
+	char *page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	char *p = page;
 	ssize_t ret;
 
 	if (!p)
@@ -396,11 +394,10 @@ mwifiex_debug_read(struct file *file, char __user *ubuf,
 
 	p += mwifiex_debug_info_to_buffer(priv, p, &info);
 
-	ret = simple_read_from_buffer(ubuf, count, ppos, (char *) page,
-				      (unsigned long) p - page);
+	ret = simple_read_from_buffer(ubuf, count, ppos, page, p - page);
 
 free_and_exit:
-	free_page(page);
+	kfree(page);
 	return ret;
 }
 
@@ -457,8 +454,7 @@ mwifiex_regrdwr_read(struct file *file, char __user *ubuf,
 {
 	struct mwifiex_private *priv =
 		(struct mwifiex_private *) file->private_data;
-	unsigned long addr = get_zeroed_page(GFP_KERNEL);
-	char *buf = (char *) addr;
+	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	int pos = 0, ret = 0;
 	u32 reg_value;
 
@@ -497,7 +493,7 @@ mwifiex_regrdwr_read(struct file *file, char __user *ubuf,
 	ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos);
 
 done:
-	free_page(addr);
+	kfree(buf);
 	return ret;
 }
 
@@ -511,8 +507,7 @@ mwifiex_debug_mask_read(struct file *file, char __user *ubuf,
 {
 	struct mwifiex_private *priv =
 		(struct mwifiex_private *)file->private_data;
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
-	char *buf = (char *)page;
+	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	size_t ret = 0;
 	int pos = 0;
 
@@ -523,7 +518,7 @@ mwifiex_debug_mask_read(struct file *file, char __user *ubuf,
 			priv->adapter->debug_mask);
 	ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos);
 
-	free_page(page);
+	kfree(buf);
 	return ret;
 }
 
@@ -652,8 +647,7 @@ mwifiex_memrw_read(struct file *file, char __user *ubuf,
 		   size_t count, loff_t *ppos)
 {
 	struct mwifiex_private *priv = (void *)file->private_data;
-	unsigned long addr = get_zeroed_page(GFP_KERNEL);
-	char *buf = (char *)addr;
+	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	int ret, pos = 0;
 
 	if (!buf)
@@ -663,7 +657,7 @@ mwifiex_memrw_read(struct file *file, char __user *ubuf,
 			priv->mem_rw.value);
 	ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos);
 
-	free_page(addr);
+	kfree(buf);
 	return ret;
 }
 
@@ -719,8 +713,7 @@ mwifiex_rdeeprom_read(struct file *file, char __user *ubuf,
 {
 	struct mwifiex_private *priv =
 		(struct mwifiex_private *) file->private_data;
-	unsigned long addr = get_zeroed_page(GFP_KERNEL);
-	char *buf = (char *) addr;
+	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	int pos, ret, i;
 	u8 value[MAX_EEPROM_DATA];
 
@@ -749,7 +742,7 @@ mwifiex_rdeeprom_read(struct file *file, char __user *ubuf,
 done:
 	ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos);
 out_free:
-	free_page(addr);
+	kfree(buf);
 	return ret;
 }
 
@@ -820,8 +813,7 @@ mwifiex_hscfg_read(struct file *file, char __user *ubuf,
 		   size_t count, loff_t *ppos)
 {
 	struct mwifiex_private *priv = (void *)file->private_data;
-	unsigned long addr = get_zeroed_page(GFP_KERNEL);
-	char *buf = (char *)addr;
+	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	int pos, ret;
 	struct mwifiex_ds_hs_cfg hscfg;
 
@@ -836,7 +828,7 @@ mwifiex_hscfg_read(struct file *file, char __user *ubuf,
 
 	ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos);
 
-	free_page(addr);
+	kfree(buf);
 	return ret;
 }
 

-- 
2.53.0