Commit d38aa396 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Jakub Kicinski
Browse files

s390/ctcm: Avoid temporary allocation of struct qllc. 



The size of struct qllc is 2 byte. The memory for is allocated,
initialized, used and deallocated a few lines later.

It is more efficient to avoid the allocation/free dance and assign the
values directly to skb's data part instead of using memcpy() for it.

Avoid an allocation of struct qllc and use the resulting skb pointer
instead.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
[jwi: remove a newline, reflow the commit msg]
Signed-off-by: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 94e0028a

drivers/s390/net/ctcm_mpc.c

+4 −17
Original line number Diff line number Diff line
@@ -2048,7 +2048,6 @@ static void mpc_action_rcvd_xid7(fsm_instance *fsm, int event, void *arg) 
 */

static int mpc_send_qllc_discontact(struct net_device *dev)

{

	__u32	new_len	= 0;

	struct sk_buff   *skb;

	struct qllc      *qllcptr;

	struct ctcm_priv *priv = dev->ml_priv;
@@ -2079,31 +2078,19 @@ static int mpc_send_qllc_discontact(struct net_device *dev) 
	case MPCG_STATE_FLOWC:

	case MPCG_STATE_READY:

		grp->send_qllc_disc = 2;

		new_len = sizeof(struct qllc);

		qllcptr = kzalloc(new_len, gfp_type() | GFP_DMA);

		if (qllcptr == NULL) {

			CTCM_DBF_TEXT_(MPC_ERROR, CTC_DBF_ERROR,

				"%s(%s): qllcptr allocation error",

						CTCM_FUNTAIL, dev->name);

			return -ENOMEM;

		}



		qllcptr->qllc_address = 0xcc;

		qllcptr->qllc_commands = 0x03;



		skb = __dev_alloc_skb(new_len, GFP_ATOMIC);



		skb = __dev_alloc_skb(sizeof(struct qllc), GFP_ATOMIC);

		if (skb == NULL) {

			CTCM_DBF_TEXT_(MPC_ERROR, CTC_DBF_ERROR,

				"%s(%s): skb allocation error",

						CTCM_FUNTAIL, dev->name);

			priv->stats.rx_dropped++;

			kfree(qllcptr);

			return -ENOMEM;

		}



		skb_put_data(skb, qllcptr, new_len);

		kfree(qllcptr);

		qllcptr = skb_put(skb, sizeof(struct qllc));

		qllcptr->qllc_address = 0xcc;

		qllcptr->qllc_commands = 0x03;



		if (skb_headroom(skb) < 4) {

			CTCM_DBF_TEXT_(MPC_ERROR, CTC_DBF_ERROR,

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