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s390/ctcm: Avoid temporary allocation of struct th_header and th_sweep.

Browse source 
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: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[jwi: use skb_put_zero(), instead of skb_put() + memset to 0]
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 11:09:45 +01:00 committed by Jakub Kicinski
parent 2bf7d3776b
commit 94e0028a05
3 changed files with 9 additions and 53 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
drivers/s390/net/ctcm_fsms.c
View file

@ -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 "

31
drivers/s390/net/ctcm_main.c
View file

@ -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);

16
drivers/s390/net/ctcm_mpc.c
View file

@ -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);