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s390/ctcm: Avoid temporary allocation of struct qllc.

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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: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[jwi: remove a newline, reflow the commit msg]
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Sebastian Andrzej Siewior
2020-11-30 11:09:46 +01:00
committed by Jakub Kicinski
parent 94e0028a05
commit d38aa39626
1 changed files with 4 additions and 17 deletions
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21
drivers/s390/net/ctcm_mpc.c
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@@ -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,