[RFC 1/1] drivers/scsi/bfa/bfad_debugfs.c: replace 2 kzalloc/copy_from_user to memdup_user

[RFC 1/1] drivers/scsi/bfa/bfad_debugfs.c: replace 2 kzalloc/copy_from_user to memdup_user

[Fabian Frederick]

(memdup_user can be used to replace kmalloc/copy_from_user. Not sure if it's ok with kzalloc ...)

Cc: linux-scsi@vger.kernel.org
Cc: Anil Gurumurthy <anil.gurumurthy@qlogic.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
---
 drivers/scsi/bfa/bfad_debugfs.c | 30 ++++++++++--------------------
 1 file changed, 10 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/bfa/bfad_debugfs.c b/drivers/scsi/bfa/bfad_debugfs.c
index 8e83d04..07b9e36 100644
--- a/drivers/scsi/bfa/bfad_debugfs.c
+++ b/drivers/scsi/bfa/bfad_debugfs.c
@@ -260,17 +260,12 @@ bfad_debugfs_write_regrd(struct file *file, const char __user *buf,
 	unsigned long flags;
 	void *kern_buf;
 
-	kern_buf = kzalloc(nbytes, GFP_KERNEL);
+	kern_buf = memdup_user((void __user *)buf, nbytes);
 
-	if (!kern_buf) {
-		printk(KERN_INFO "bfad[%d]: Failed to allocate buffer\n",
-				bfad->inst_no);
-		return -ENOMEM;
-	}
-
-	if (copy_from_user(kern_buf, (void  __user *)buf, nbytes)) {
-		kfree(kern_buf);
-		return -ENOMEM;
+	if (IS_ERR(kern_buf)) {
+		printk(KERN_INFO "bfad[%d]: Failed to copy buffer\n",
+		       bfad->inst_no);
+		return PTR_ERR(kern_buf);
 	}
 
 	rc = sscanf(kern_buf, "%x:%x", &addr, &len);
@@ -336,17 +331,12 @@ bfad_debugfs_write_regwr(struct file *file, const char __user *buf,
 	unsigned long flags;
 	void *kern_buf;
 
-	kern_buf = kzalloc(nbytes, GFP_KERNEL);
+	kern_buf = memdup_user((void __user *)buf, nbytes);
 
-	if (!kern_buf) {
-		printk(KERN_INFO "bfad[%d]: Failed to allocate buffer\n",
-				bfad->inst_no);
-		return -ENOMEM;
-	}
-
-	if (copy_from_user(kern_buf, (void  __user *)buf, nbytes)) {
-		kfree(kern_buf);
-		return -ENOMEM;
+	if (IS_ERR(kern_buf)) {
+		printk(KERN_INFO "bfad[%d]: Failed to copy buffer\n",
+		       bfad->inst_no);
+		return PTR_ERR(kern_buf);
 	}
 
 	rc = sscanf(kern_buf, "%x:%x", &addr, &val);
-- 
1.8.4.5

Re: [RFC 1/1] drivers/scsi/bfa/bfad_debugfs.c: replace 2 kzalloc/copy_from_user to memdup_user

[One Thousand Gnomes]

On Fri, 30 May 2014 19:07:36 +0200
Fabian Frederick <fabf@skynet.be> wrote:

> (memdup_user can be used to replace kmalloc/copy_from_user. Not sure if it's ok with kzalloc ...)


> +	kern_buf = memdup_user((void __user *)buf, nbytes);

> +	if (IS_ERR(kern_buf)) {
> +		printk(KERN_INFO "bfad[%d]: Failed to copy buffer\n",
> +		       bfad->inst_no);

While you are tidying up lose the printk KERN_INFO stuff here, it really
isn't needed.

Looks good to me and it also fixes the incorrect return of -ENOMEM the
old code had on a copy_from_user failing.

Alan