linux-kernel - [PATCH] mlx5/core: Use memdup_user() rather than duplicating its implementation

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Date:   Sat, 20 Aug 2016 08:01:22 +0200
From:   SF Markus Elfring <elfring@...rs.sourceforge.net>
To:     linux-rdma@...r.kernel.org, netdev@...r.kernel.org,
        Leon Romanovsky <leonro@...lanox.com>,
        Matan Barak <matanb@...lanox.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Julia Lawall <julia.lawall@...6.fr>
Subject: [PATCH] mlx5/core: Use memdup_user() rather than duplicating its
 implementation

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Sat, 20 Aug 2016 07:50:09 +0200

* Reuse existing functionality from memdup_user() instead of keeping
  duplicate source code.

  This issue was detected by using the Coccinelle software.

* Return directly if this copy operation failed.

Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
---
 drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
index 6388bc0..bb89f04 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
@@ -1132,7 +1132,6 @@ static ssize_t data_write(struct file *filp, const char __user *buf,
 	struct mlx5_core_dev *dev = filp->private_data;
 	struct mlx5_cmd_debug *dbg = &dev->cmd.dbg;
 	void *ptr;
-	int err;
 
 	if (*pos != 0)
 		return -EINVAL;
@@ -1140,25 +1139,15 @@ static ssize_t data_write(struct file *filp, const char __user *buf,
 	kfree(dbg->in_msg);
 	dbg->in_msg = NULL;
 	dbg->inlen = 0;
-
-	ptr = kzalloc(count, GFP_KERNEL);
-	if (!ptr)
-		return -ENOMEM;
-
-	if (copy_from_user(ptr, buf, count)) {
-		err = -EFAULT;
-		goto out;
-	}
+	ptr = memdup_user(buf, count);
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
 	dbg->in_msg = ptr;
 	dbg->inlen = count;
 
 	*pos = count;
 
 	return count;
-
-out:
-	kfree(ptr);
-	return err;
 }
 
 static ssize_t data_read(struct file *filp, char __user *buf, size_t count,
-- 
2.9.3