[PATCH net-next 0/5] net/iucv: updates 2021-08-09

[PATCH net-next 0/5] net/iucv: updates 2021-08-09

[Karsten Graul]

Please apply the following iucv patches to netdev's net-next tree.

Remove the usage of register asm statements and replace deprecated
CPU-hotplug functions with the current version.
Use use consume_skb() instead of kfree_skb() to avoid flooding
dropwatch with false-positives, and 2 patches with cleanups.

Heiko Carstens (1):
  net/iucv: get rid of register asm usage

Julian Wiedmann (3):
  net/af_iucv: support drop monitoring
  net/af_iucv: clean up a try_then_request_module()
  net/af_iucv: remove wrappers around iucv (de-)registration

Sebastian Andrzej Siewior (1):
  net/iucv: Replace deprecated CPU-hotplug functions.

 net/iucv/af_iucv.c | 72 ++++++++++++++++++----------------------------
 net/iucv/iucv.c    | 60 +++++++++++++++++++-------------------
 2 files changed, 59 insertions(+), 73 deletions(-)

-- 
2.25.1

[PATCH net-next 1/5] net/af_iucv: support drop monitoring

[Karsten Graul]

From: Julian Wiedmann <jwi@linux.ibm.com>

Change the good paths to use consume_skb() instead of kfree_skb(). This
avoids flooding dropwatch with false-positives.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/iucv/af_iucv.c | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 44453b35c7b7..c8fbfc0be2e5 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1044,7 +1044,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
 			if (err == 0) {
 				atomic_dec(&iucv->skbs_in_xmit);
 				skb_unlink(skb, &iucv->send_skb_q);
-				kfree_skb(skb);
+				consume_skb(skb);
 			}
 
 			/* this error should never happen since the	*/
@@ -1293,7 +1293,7 @@ static int iucv_sock_recvmsg(struct socket *sock, struct msghdr *msg,
 			}
 		}
 
-		kfree_skb(skb);
+		consume_skb(skb);
 		if (iucv->transport == AF_IUCV_TRANS_HIPER) {
 			atomic_inc(&iucv->msg_recv);
 			if (atomic_read(&iucv->msg_recv) > iucv->msglimit) {
@@ -1756,7 +1756,7 @@ static void iucv_callback_txdone(struct iucv_path *path,
 	spin_unlock_irqrestore(&list->lock, flags);
 
 	if (this) {
-		kfree_skb(this);
+		consume_skb(this);
 		/* wake up any process waiting for sending */
 		iucv_sock_wake_msglim(sk);
 	}
@@ -1903,17 +1903,17 @@ static int afiucv_hs_callback_synack(struct sock *sk, struct sk_buff *skb)
 {
 	struct iucv_sock *iucv = iucv_sk(sk);
 
-	if (!iucv)
-		goto out;
-	if (sk->sk_state != IUCV_BOUND)
-		goto out;
+	if (!iucv || sk->sk_state != IUCV_BOUND) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
 	bh_lock_sock(sk);
 	iucv->msglimit_peer = iucv_trans_hdr(skb)->window;
 	sk->sk_state = IUCV_CONNECTED;
 	sk->sk_state_change(sk);
 	bh_unlock_sock(sk);
-out:
-	kfree_skb(skb);
+	consume_skb(skb);
 	return NET_RX_SUCCESS;
 }
 
@@ -1924,16 +1924,16 @@ static int afiucv_hs_callback_synfin(struct sock *sk, struct sk_buff *skb)
 {
 	struct iucv_sock *iucv = iucv_sk(sk);
 
-	if (!iucv)
-		goto out;
-	if (sk->sk_state != IUCV_BOUND)
-		goto out;
+	if (!iucv || sk->sk_state != IUCV_BOUND) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
 	bh_lock_sock(sk);
 	sk->sk_state = IUCV_DISCONN;
 	sk->sk_state_change(sk);
 	bh_unlock_sock(sk);
-out:
-	kfree_skb(skb);
+	consume_skb(skb);
 	return NET_RX_SUCCESS;
 }
 
@@ -1945,16 +1945,18 @@ static int afiucv_hs_callback_fin(struct sock *sk, struct sk_buff *skb)
 	struct iucv_sock *iucv = iucv_sk(sk);
 
 	/* other end of connection closed */
-	if (!iucv)
-		goto out;
+	if (!iucv) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
 	bh_lock_sock(sk);
 	if (sk->sk_state == IUCV_CONNECTED) {
 		sk->sk_state = IUCV_DISCONN;
 		sk->sk_state_change(sk);
 	}
 	bh_unlock_sock(sk);
-out:
-	kfree_skb(skb);
+	consume_skb(skb);
 	return NET_RX_SUCCESS;
 }
 
@@ -2107,7 +2109,7 @@ static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
 	case (AF_IUCV_FLAG_WIN):
 		err = afiucv_hs_callback_win(sk, skb);
 		if (skb->len == sizeof(struct af_iucv_trans_hdr)) {
-			kfree_skb(skb);
+			consume_skb(skb);
 			break;
 		}
 		fallthrough;	/* and receive non-zero length data */
-- 
2.25.1

[PATCH net-next 2/5] net/af_iucv: clean up a try_then_request_module()

[Karsten Graul]

From: Julian Wiedmann <jwi@linux.ibm.com>

Use IS_ENABLED(CONFIG_IUCV) to determine whether the iucv_if symbol
is available, and let depmod deal with the module dependency.

This was introduced back with commit 6fcd61f7bf5d ("af_iucv: use
loadable iucv interface"). And to avoid sprinkling IS_ENABLED() over
all the code, we're keeping the indirection through pr_iucv->...().

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/iucv/af_iucv.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index c8fbfc0be2e5..4bff26f7faff 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -2278,7 +2278,7 @@ static int __init afiucv_init(void)
 {
 	int err;
 
-	if (MACHINE_IS_VM) {
+	if (MACHINE_IS_VM && IS_ENABLED(CONFIG_IUCV)) {
 		cpcmd("QUERY USERID", iucv_userid, sizeof(iucv_userid), &err);
 		if (unlikely(err)) {
 			WARN_ON(err);
@@ -2286,11 +2286,7 @@ static int __init afiucv_init(void)
 			goto out;
 		}
 
-		pr_iucv = try_then_request_module(symbol_get(iucv_if), "iucv");
-		if (!pr_iucv) {
-			printk(KERN_WARNING "iucv_if lookup failed\n");
-			memset(&iucv_userid, 0, sizeof(iucv_userid));
-		}
+		pr_iucv = &iucv_if;
 	} else {
 		memset(&iucv_userid, 0, sizeof(iucv_userid));
 		pr_iucv = NULL;
@@ -2324,17 +2320,13 @@ static int __init afiucv_init(void)
 out_proto:
 	proto_unregister(&iucv_proto);
 out:
-	if (pr_iucv)
-		symbol_put(iucv_if);
 	return err;
 }
 
 static void __exit afiucv_exit(void)
 {
-	if (pr_iucv) {
+	if (pr_iucv)
 		afiucv_iucv_exit();
-		symbol_put(iucv_if);
-	}
 
 	unregister_netdevice_notifier(&afiucv_netdev_notifier);
 	dev_remove_pack(&iucv_packet_type);
-- 
2.25.1

[PATCH net-next 3/5] net/af_iucv: remove wrappers around iucv (de-)registration

[Karsten Graul]

From: Julian Wiedmann <jwi@linux.ibm.com>

These wrappers are just unnecessary obfuscation.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/iucv/af_iucv.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 4bff26f7faff..18316ee3c692 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -2264,16 +2264,6 @@ static struct packet_type iucv_packet_type = {
 	.func = afiucv_hs_rcv,
 };
 
-static int afiucv_iucv_init(void)
-{
-	return pr_iucv->iucv_register(&af_iucv_handler, 0);
-}
-
-static void afiucv_iucv_exit(void)
-{
-	pr_iucv->iucv_unregister(&af_iucv_handler, 0);
-}
-
 static int __init afiucv_init(void)
 {
 	int err;
@@ -2300,7 +2290,7 @@ static int __init afiucv_init(void)
 		goto out_proto;
 
 	if (pr_iucv) {
-		err = afiucv_iucv_init();
+		err = pr_iucv->iucv_register(&af_iucv_handler, 0);
 		if (err)
 			goto out_sock;
 	}
@@ -2314,7 +2304,7 @@ static int __init afiucv_init(void)
 
 out_notifier:
 	if (pr_iucv)
-		afiucv_iucv_exit();
+		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
 out_sock:
 	sock_unregister(PF_IUCV);
 out_proto:
@@ -2326,7 +2316,7 @@ static int __init afiucv_init(void)
 static void __exit afiucv_exit(void)
 {
 	if (pr_iucv)
-		afiucv_iucv_exit();
+		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
 
 	unregister_netdevice_notifier(&afiucv_netdev_notifier);
 	dev_remove_pack(&iucv_packet_type);
-- 
2.25.1

[PATCH net-next 4/5] net/iucv: get rid of register asm usage

[Karsten Graul]

From: Heiko Carstens <hca@linux.ibm.com>

Using register asm statements has been proven to be very error prone,
especially when using code instrumentation where gcc may add function
calls, which clobbers register contents in an unexpected way.

Therefore get rid of register asm statements in iucv code, even though
there is currently nothing wrong with it. This way we know for sure
that the above mentioned bug class won't be introduced here.

Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/iucv/iucv.c | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index e6795d5a546a..bebc7d09815d 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -286,19 +286,19 @@ static union iucv_param *iucv_param_irq[NR_CPUS];
  */
 static inline int __iucv_call_b2f0(int command, union iucv_param *parm)
 {
-	register unsigned long reg0 asm ("0");
-	register unsigned long reg1 asm ("1");
-	int ccode;
+	int cc;
 
-	reg0 = command;
-	reg1 = (unsigned long)parm;
 	asm volatile(
-		"	.long 0xb2f01000\n"
-		"	ipm	%0\n"
-		"	srl	%0,28\n"
-		: "=d" (ccode), "=m" (*parm), "+d" (reg0), "+a" (reg1)
-		:  "m" (*parm) : "cc");
-	return ccode;
+		"	lgr	0,%[reg0]\n"
+		"	lgr	1,%[reg1]\n"
+		"	.long	0xb2f01000\n"
+		"	ipm	%[cc]\n"
+		"	srl	%[cc],28\n"
+		: [cc] "=&d" (cc), "+m" (*parm)
+		: [reg0] "d" ((unsigned long)command),
+		  [reg1] "d" ((unsigned long)parm)
+		: "cc", "0", "1");
+	return cc;
 }
 
 static inline int iucv_call_b2f0(int command, union iucv_param *parm)
@@ -319,19 +319,21 @@ static inline int iucv_call_b2f0(int command, union iucv_param *parm)
  */
 static int __iucv_query_maxconn(void *param, unsigned long *max_pathid)
 {
-	register unsigned long reg0 asm ("0");
-	register unsigned long reg1 asm ("1");
-	int ccode;
+	unsigned long reg1 = (unsigned long)param;
+	int cc;
 
-	reg0 = IUCV_QUERY;
-	reg1 = (unsigned long) param;
 	asm volatile (
+		"	lghi	0,%[cmd]\n"
+		"	lgr	1,%[reg1]\n"
 		"	.long	0xb2f01000\n"
-		"	ipm	%0\n"
-		"	srl	%0,28\n"
-		: "=d" (ccode), "+d" (reg0), "+d" (reg1) : : "cc");
+		"	ipm	%[cc]\n"
+		"	srl	%[cc],28\n"
+		"	lgr	%[reg1],1\n"
+		: [cc] "=&d" (cc), [reg1] "+&d" (reg1)
+		: [cmd] "K" (IUCV_QUERY)
+		: "cc", "0", "1");
 	*max_pathid = reg1;
-	return ccode;
+	return cc;
 }
 
 static int iucv_query_maxconn(void)
-- 
2.25.1

[PATCH net-next 5/5] net/iucv: Replace deprecated CPU-hotplug functions.

[Karsten Graul]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Cc: Julian Wiedmann <jwi@linux.ibm.com>
Cc: Karsten Graul <kgraul@linux.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: linux-s390@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/iucv/iucv.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index bebc7d09815d..f3343a8541a5 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -502,14 +502,14 @@ static void iucv_setmask_mp(void)
 {
 	int cpu;
 
-	get_online_cpus();
+	cpus_read_lock();
 	for_each_online_cpu(cpu)
 		/* Enable all cpus with a declared buffer. */
 		if (cpumask_test_cpu(cpu, &iucv_buffer_cpumask) &&
 		    !cpumask_test_cpu(cpu, &iucv_irq_cpumask))
 			smp_call_function_single(cpu, iucv_allow_cpu,
 						 NULL, 1);
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 /**
@@ -542,7 +542,7 @@ static int iucv_enable(void)
 	size_t alloc_size;
 	int cpu, rc;
 
-	get_online_cpus();
+	cpus_read_lock();
 	rc = -ENOMEM;
 	alloc_size = iucv_max_pathid * sizeof(struct iucv_path);
 	iucv_path_table = kzalloc(alloc_size, GFP_KERNEL);
@@ -555,12 +555,12 @@ static int iucv_enable(void)
 	if (cpumask_empty(&iucv_buffer_cpumask))
 		/* No cpu could declare an iucv buffer. */
 		goto out;
-	put_online_cpus();
+	cpus_read_unlock();
 	return 0;
 out:
 	kfree(iucv_path_table);
 	iucv_path_table = NULL;
-	put_online_cpus();
+	cpus_read_unlock();
 	return rc;
 }
 
@@ -573,11 +573,11 @@ static int iucv_enable(void)
  */
 static void iucv_disable(void)
 {
-	get_online_cpus();
+	cpus_read_lock();
 	on_each_cpu(iucv_retrieve_cpu, NULL, 1);
 	kfree(iucv_path_table);
 	iucv_path_table = NULL;
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 static int iucv_cpu_dead(unsigned int cpu)
@@ -786,7 +786,7 @@ static int iucv_reboot_event(struct notifier_block *this,
 	if (cpumask_empty(&iucv_irq_cpumask))
 		return NOTIFY_DONE;
 
-	get_online_cpus();
+	cpus_read_lock();
 	on_each_cpu_mask(&iucv_irq_cpumask, iucv_block_cpu, NULL, 1);
 	preempt_disable();
 	for (i = 0; i < iucv_max_pathid; i++) {
@@ -794,7 +794,7 @@ static int iucv_reboot_event(struct notifier_block *this,
 			iucv_sever_pathid(i, NULL);
 	}
 	preempt_enable();
-	put_online_cpus();
+	cpus_read_unlock();
 	iucv_disable();
 	return NOTIFY_DONE;
 }
-- 
2.25.1

Re: [PATCH net-next 0/5] net/iucv: updates 2021-08-09

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (refs/heads/master):

On Mon,  9 Aug 2021 10:30:45 +0200 you wrote:
> Please apply the following iucv patches to netdev's net-next tree.
> 
> Remove the usage of register asm statements and replace deprecated
> CPU-hotplug functions with the current version.
> Use use consume_skb() instead of kfree_skb() to avoid flooding
> dropwatch with false-positives, and 2 patches with cleanups.
> 
> [...]

Here is the summary with links:
  - [net-next,1/5] net/af_iucv: support drop monitoring
    https://git.kernel.org/netdev/net-next/c/10d6393dc471
  - [net-next,2/5] net/af_iucv: clean up a try_then_request_module()
    https://git.kernel.org/netdev/net-next/c/4eb9eda6ba64
  - [net-next,3/5] net/af_iucv: remove wrappers around iucv (de-)registration
    https://git.kernel.org/netdev/net-next/c/ff8424be8ce3
  - [net-next,4/5] net/iucv: get rid of register asm usage
    https://git.kernel.org/netdev/net-next/c/50348fac2921
  - [net-next,5/5] net/iucv: Replace deprecated CPU-hotplug functions.
    https://git.kernel.org/netdev/net-next/c/8c39ed4876d4

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html