Merge branch 's390-ctcm-updates-2020-11-30'

Julian Wiedmann says:

====================
s390/ctcm: updates 2020-11-30

Some rare ctcm updates by Sebastian, who cleans up all places where
in_interrupt() was used to determine the correct GFP_* mask for
allocations.
In the first three patches we can get rid of those allocations entirely,
as they just end up being copied into the skb.
====================

Link: https://lore.kernel.org/r/20201130100950.42051-1-jwi@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 24 insertions, 103 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..fd705429708e 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);
 
@@ -680,24 +665,16 @@ static int ctcmpc_transmit_skb(struct channel *ch, struct sk_buff *skb)
 	if ((fsm_getstate(ch->fsm) != CTC_STATE_TXIDLE) || grp->in_sweep) {
 		spin_lock_irqsave(&ch->collect_lock, saveflags);
 		refcount_inc(&skb->users);
-		p_header = kmalloc(PDU_HEADER_LENGTH, gfp_type());
-
-		if (!p_header) {
-			spin_unlock_irqrestore(&ch->collect_lock, saveflags);
-				goto nomem_exit;
-		}
 
-		p_header->pdu_offset = skb->len;
+		p_header = skb_push(skb, PDU_HEADER_LENGTH);
+		p_header->pdu_offset = skb->len - PDU_HEADER_LENGTH;
 		p_header->pdu_proto = 0x01;
-		p_header->pdu_flag = 0x00;
 		if (be16_to_cpu(skb->protocol) == ETH_P_SNAP) {
-			p_header->pdu_flag |= PDU_FIRST | PDU_CNTL;
+			p_header->pdu_flag = PDU_FIRST | PDU_CNTL;
 		} else {
-			p_header->pdu_flag |= PDU_FIRST;
+			p_header->pdu_flag = PDU_FIRST;
 		}
 		p_header->pdu_seq = 0;
-		memcpy(skb_push(skb, PDU_HEADER_LENGTH), p_header,
-		       PDU_HEADER_LENGTH);
 
 		CTCM_PR_DEBUG("%s(%s): Put on collect_q - skb len: %04x \n"
 				"pdu header and data for up to 32 bytes:\n",
@@ -706,7 +683,6 @@ static int ctcmpc_transmit_skb(struct channel *ch, struct sk_buff *skb)
 
 		skb_queue_tail(&ch->collect_queue, skb);
 		ch->collect_len += skb->len;
-		kfree(p_header);
 
 		spin_unlock_irqrestore(&ch->collect_lock, saveflags);
 			goto done;
@@ -736,23 +712,15 @@ static int ctcmpc_transmit_skb(struct channel *ch, struct sk_buff *skb)
 		}
 	}
 
-	p_header = kmalloc(PDU_HEADER_LENGTH, gfp_type());
-
-	if (!p_header)
-		goto nomem_exit;
-
-	p_header->pdu_offset = skb->len;
+	p_header = skb_push(skb, PDU_HEADER_LENGTH);
+	p_header->pdu_offset = skb->len - PDU_HEADER_LENGTH;
 	p_header->pdu_proto = 0x01;
-	p_header->pdu_flag = 0x00;
 	p_header->pdu_seq = 0;
 	if (be16_to_cpu(skb->protocol) == ETH_P_SNAP) {
-		p_header->pdu_flag |= PDU_FIRST | PDU_CNTL;
+		p_header->pdu_flag = PDU_FIRST | PDU_CNTL;
 	} else {
-		p_header->pdu_flag |= PDU_FIRST;
+		p_header->pdu_flag = PDU_FIRST;
 	}
-	memcpy(skb_push(skb, PDU_HEADER_LENGTH), p_header, PDU_HEADER_LENGTH);
-
-	kfree(p_header);
 
 	if (ch->collect_len > 0) {
 		spin_lock_irqsave(&ch->collect_lock, saveflags);
@@ -768,25 +736,17 @@ 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);
@@ -943,7 +903,7 @@ static int ctcmpc_tx(struct sk_buff *skb, struct net_device *dev)
 		CTCM_D3_DUMP((char *)skb->data, min_t(int, 32, skb->len));
 
 		len =  skb->len + TH_HEADER_LENGTH + PDU_HEADER_LENGTH;
-		newskb = __dev_alloc_skb(len, gfp_type() | GFP_DMA);
+		newskb = __dev_alloc_skb(len, GFP_ATOMIC | GFP_DMA);
 
 		if (!newskb) {
 			CTCM_DBF_TEXT_(MPC_TRACE, CTC_DBF_ERROR,
@@ -1361,7 +1321,7 @@ static int add_channel(struct ccw_device *cdev, enum ctcm_channel_types type,
 
 	ch->protocol = priv->protocol;
 	if (IS_MPC(priv)) {
-		ch->discontact_th = kzalloc(TH_HEADER_LENGTH, gfp_type());
+		ch->discontact_th = kzalloc(TH_HEADER_LENGTH, GFP_KERNEL);
 		if (ch->discontact_th == NULL)
 					goto nomem_return;
 
diff --git a/drivers/s390/net/ctcm_main.h b/drivers/s390/net/ctcm_main.h
index 16bdf23ee02b..90bd7b3f80c3 100644
--- a/drivers/s390/net/ctcm_main.h
+++ b/drivers/s390/net/ctcm_main.h
@@ -298,11 +298,6 @@ struct mpc_group *ctcmpc_init_mpc_group(struct ctcm_priv *priv);
 /* test if struct ctcm_priv of struct net_device has MPC protocol setting */
 #define IS_MPCDEV(dev) IS_MPC((struct ctcm_priv *)dev->ml_priv)
 
-static inline gfp_t gfp_type(void)
-{
-	return in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
-}
-
 /*
  * Definition of our link level header.
  */
diff --git a/drivers/s390/net/ctcm_mpc.c b/drivers/s390/net/ctcm_mpc.c
index 85a1a4533cbe..19ee91acb89d 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);
 
@@ -1177,7 +1163,7 @@ static void ctcmpc_unpack_skb(struct channel *ch, struct sk_buff *pskb)
 			skb_pull(pskb, new_len); /* point to next PDU */
 		}
 	} else {
-		mpcginfo = kmalloc(sizeof(struct mpcg_info), gfp_type());
+		mpcginfo = kmalloc(sizeof(struct mpcg_info), GFP_ATOMIC);
 		if (mpcginfo == NULL)
 					goto done;
 
@@ -2062,7 +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;
@@ -2093,31 +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,