Commit 94e0028a authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Jakub Kicinski
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s390/ctcm: Avoid temporary allocation of struct th_header and th_sweep. 



The size of struct th_header is 8 byte and the size of struct th_sweep
is 16 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 th_sweep/th_header and use the resulting
skb pointer instead.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
[jwi: use skb_put_zero(), instead of skb_put() + memset to 0]
Signed-off-by: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2bf7d377

drivers/s390/net/ctcm_fsms.c

+4 −11
Original line number Diff line number Diff line
@@ -1303,12 +1303,10 @@ static void ctcmpc_chx_txdone(fsm_instance *fi, int event, void *arg) 
	/* p_header points to the last one we handled */

	if (p_header)

		p_header->pdu_flag |= PDU_LAST;	/*Say it's the last one*/

	header = kzalloc(TH_HEADER_LENGTH, gfp_type());

	if (!header) {

		spin_unlock(&ch->collect_lock);

		fsm_event(priv->mpcg->fsm, MPCG_EVENT_INOP, dev);

				goto done;

	}



	header = skb_push(ch->trans_skb, TH_HEADER_LENGTH);

	memset(header, 0, TH_HEADER_LENGTH);



	header->th_ch_flag = TH_HAS_PDU;  /* Normal data */

	ch->th_seq_num++;

	header->th_seq_num = ch->th_seq_num;
@@ -1316,11 +1314,6 @@ static void ctcmpc_chx_txdone(fsm_instance *fi, int event, void *arg) 
	CTCM_PR_DBGDATA("%s: ToVTAM_th_seq= %08x\n" ,

					__func__, ch->th_seq_num);



	memcpy(skb_push(ch->trans_skb, TH_HEADER_LENGTH), header,

		TH_HEADER_LENGTH);	/* put the TH on the packet */



	kfree(header);



	CTCM_PR_DBGDATA("%s: trans_skb len:%04x \n",

		       __func__, ch->trans_skb->len);

	CTCM_PR_DBGDATA("%s: up-to-50 bytes of trans_skb "

drivers/s390/net/ctcm_main.c

+4 −27
Original line number Diff line number Diff line
@@ -623,25 +623,10 @@ static void ctcmpc_send_sweep_req(struct channel *rch) 
				goto nomem;

	}



	header = kmalloc(TH_SWEEP_LENGTH, gfp_type());



	if (!header) {

		dev_kfree_skb_any(sweep_skb);

		/* rc = -ENOMEM; */

				goto nomem;

	}



	header->th.th_seg	= 0x00 ;

	header = skb_put_zero(sweep_skb, TH_SWEEP_LENGTH);

	header->th.th_ch_flag	= TH_SWEEP_REQ;  /* 0x0f */

	header->th.th_blk_flag	= 0x00;

	header->th.th_is_xid	= 0x00;

	header->th.th_seq_num	= 0x00;

	header->sw.th_last_seq	= ch->th_seq_num;



	skb_put_data(sweep_skb, header, TH_SWEEP_LENGTH);



	kfree(header);



	netif_trans_update(dev);

	skb_queue_tail(&ch->sweep_queue, sweep_skb);
@@ -768,25 +753,17 @@ static int ctcmpc_transmit_skb(struct channel *ch, struct sk_buff *skb) 


	ch->prof.txlen += skb->len - PDU_HEADER_LENGTH;



	header = kmalloc(TH_HEADER_LENGTH, gfp_type());

	if (!header)

		goto nomem_exit;

	/* put the TH on the packet */

	header = skb_push(skb, TH_HEADER_LENGTH);

	memset(header, 0, TH_HEADER_LENGTH);



	header->th_seg = 0x00;

	header->th_ch_flag = TH_HAS_PDU;  /* Normal data */

	header->th_blk_flag = 0x00;

	header->th_is_xid = 0x00;          /* Just data here */

	ch->th_seq_num++;

	header->th_seq_num = ch->th_seq_num;



	CTCM_PR_DBGDATA("%s(%s) ToVTAM_th_seq= %08x\n" ,

		       __func__, dev->name, ch->th_seq_num);



	/* put the TH on the packet */

	memcpy(skb_push(skb, TH_HEADER_LENGTH), header, TH_HEADER_LENGTH);



	kfree(header);



	CTCM_PR_DBGDATA("%s(%s): skb len: %04x\n - pdu header and data for "

			"up to 32 bytes sent to vtam:\n",

				__func__, dev->name, skb->len);

drivers/s390/net/ctcm_mpc.c

+1 −15
Original line number Diff line number Diff line
@@ -655,24 +655,10 @@ static void ctcmpc_send_sweep_resp(struct channel *rch) 
		goto done;

	}



	header = kmalloc(sizeof(struct th_sweep), gfp_type());



	if (!header) {

		dev_kfree_skb_any(sweep_skb);

		goto done;

	}



	header->th.th_seg	= 0x00 ;

	header = skb_put_zero(sweep_skb, TH_SWEEP_LENGTH);

	header->th.th_ch_flag	= TH_SWEEP_RESP;

	header->th.th_blk_flag	= 0x00;

	header->th.th_is_xid	= 0x00;

	header->th.th_seq_num	= 0x00;

	header->sw.th_last_seq	= ch->th_seq_num;



	skb_put_data(sweep_skb, header, TH_SWEEP_LENGTH);



	kfree(header);



	netif_trans_update(dev);

	skb_queue_tail(&ch->sweep_queue, sweep_skb);

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