staging/csr: Use kmemdup rather than duplicating its implementation

Author: Peter Huewe <peterhuewe@gmx.de>

Found with coccicheck.
The semantic patch that makes this change is available
in scripts/coccinelle/api/memdup.cocci.

Signed-off-by: Peter Huewe 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/staging/csr/drv.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
 
diff --git a/drivers/staging/csr/drv.c b/drivers/staging/csr/drv.c
index 4780c32..3bd52fd 100644
--- a/drivers/staging/csr/drv.c
+++ b/drivers/staging/csr/drv.c
@@ -819,15 +819,15 @@ unifi_write(struct file *filp, const char *p, size_t len, loff_t *poff)
         unifi_trace(priv, UDBG2, "unifi_write: signal 0x%.4X len:%d\n",
                     sig_id, signal_size);
 
-        /* Allocate a buffer for the signal */
-        signal_buf = kmalloc(signal_size, GFP_KERNEL);
+	/* Allocate a buffer for the signal */
+	signal_buf = kmemdup(bulkdata.d[0].os_data_ptr, signal_size,
+				GFP_KERNEL);
         if (!signal_buf) {
             unifi_net_data_free(priv, &bulkdata.d[0]);
             return -ENOMEM;
         }
 
         /* Get the signal from the os_data_ptr */
-        memcpy(signal_buf, bulkdata.d[0].os_data_ptr, signal_size);
         signal_buf[5] = (pcli->sender_id >> 8) & 0xff;
 
         if (signal_size < len) {