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Date: Mon, 30 Nov 2020 11:09:45 +0100
From: Julian Wiedmann <jwi@...ux.ibm.com>
To: David Miller <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>
Cc: linux-netdev <netdev@...r.kernel.org>,
linux-s390 <linux-s390@...r.kernel.org>,
Heiko Carstens <hca@...ux.ibm.com>,
Karsten Graul <kgraul@...ux.ibm.com>,
Julian Wiedmann <jwi@...ux.ibm.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH net-next 1/6] s390/ctcm: Avoid temporary allocation of struct th_header and th_sweep.
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
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@...utronix.de>
[jwi: use skb_put_zero(), instead of skb_put() + memset to 0]
Signed-off-by: Julian Wiedmann <jwi@...ux.ibm.com>
---
drivers/s390/net/ctcm_fsms.c | 15 ++++-----------
drivers/s390/net/ctcm_main.c | 31 ++++---------------------------
drivers/s390/net/ctcm_mpc.c | 16 +---------------
3 files changed, 9 insertions(+), 53 deletions(-)
diff --git a/drivers/s390/net/ctcm_fsms.c b/drivers/s390/net/ctcm_fsms.c
index 661d2a49bce9..b341075397d9 100644
--- a/drivers/s390/net/ctcm_fsms.c
+++ b/drivers/s390/net/ctcm_fsms.c
@@ -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 "
diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
index d06809eac16d..9e28c63415ed 100644
--- a/drivers/s390/net/ctcm_main.c
+++ b/drivers/s390/net/ctcm_main.c
@@ -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);
diff --git a/drivers/s390/net/ctcm_mpc.c b/drivers/s390/net/ctcm_mpc.c
index 85a1a4533cbe..293d8870968c 100644
--- a/drivers/s390/net/ctcm_mpc.c
+++ b/drivers/s390/net/ctcm_mpc.c
@@ -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);
--
2.17.1
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