[PATCH v2 2/4] scsi: proc: use kmalloc() in proc writers

[Mike Rapoport (Microsoft)]

proc_scsi_host_write(), proc_scsi_write() and proc_scsi_devinfo_write()
allocate temporary buffers for /proc writes using __get_free_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.

Replace use of __get_free_page() with kmalloc().

Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@xxxxxxxxxx
Reviewed-by: Hannes Reinecke <hare@xxxxxxxxxx>
Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
---
 drivers/scsi/scsi_devinfo.c | 5 +++--
 drivers/scsi/scsi_proc.c    | 9 +++++----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index 15ffbe93ac72..2bccadf4f22f 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -691,7 +691,8 @@ static ssize_t proc_scsi_devinfo_write(struct file *file,
 
 	if (!buf || length>PAGE_SIZE)
 		return -EINVAL;
-	if (!(buffer = (char *) __get_free_page(GFP_KERNEL)))
+	buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buffer)
 		return -ENOMEM;
 	if (copy_from_user(buffer, buf, length)) {
 		err =-EFAULT;
@@ -708,7 +709,7 @@ static ssize_t proc_scsi_devinfo_write(struct file *file,
 	scsi_dev_info_list_add_str(buffer);
 
 out:
-	free_page((unsigned long)buffer);
+	kfree(buffer);
 	return err;
 }
 
diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c
index 1799dcae775c..fdc355d783da 100644
--- a/drivers/scsi/scsi_proc.c
+++ b/drivers/scsi/scsi_proc.c
@@ -28,6 +28,7 @@
 #include <linux/mutex.h>
 #include <linux/gfp.h>
 #include <linux/uaccess.h>
+#include <linux/slab.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
@@ -74,7 +75,7 @@ static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf,
 	if (!shost->hostt->write_info)
 		return -EINVAL;
 
-	page = (char *)__get_free_page(GFP_KERNEL);
+	page = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (page) {
 		ret = -EFAULT;
 		if (copy_from_user(page, buf, count))
@@ -82,7 +83,7 @@ static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf,
 		ret = shost->hostt->write_info(shost, page, count);
 	}
 out:
-	free_page((unsigned long)page);
+	kfree(page);
 	return ret;
 }
 
@@ -412,7 +413,7 @@ static ssize_t proc_scsi_write(struct file *file, const char __user *buf,
 	if (!buf || length > PAGE_SIZE)
 		return -EINVAL;
 
-	buffer = (char *)__get_free_page(GFP_KERNEL);
+	buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!buffer)
 		return -ENOMEM;
 
@@ -467,7 +468,7 @@ static ssize_t proc_scsi_write(struct file *file, const char __user *buf,
 		err = length;
 
  out:
-	free_page((unsigned long)buffer);
+	kfree(buffer);
 	return err;
 }
 

-- 
2.53.0