From: Ursula Braun <ubraun@linux.ibm.com>
Date: Wed, 8 Jul 2020 17:05:14 +0200
Subject: net/smc: switch smcd_dev_list spinlock to mutex
Git-commit: 82087c0330534d18e6db25869871e589d214b7fa
Patch-mainline: v5.8-rc5
References: git-fixes

The similar smc_ib_devices spinlock has been converted to a mutex.
Protecting the smcd_dev_list by a mutex is possible as well. This
patch converts the smcd_dev_list spinlock to a mutex.

Fixes: c6ba7c9ba43d ("net/smc: add base infrastructure for SMC-D and ISM")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 net/smc/smc_core.c |    8 ++++----
 net/smc/smc_ism.c  |   11 ++++++-----
 net/smc/smc_ism.h  |    3 ++-
 net/smc/smc_pnet.c |   20 ++++++++++----------
 4 files changed, 22 insertions(+), 20 deletions(-)

--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -1274,11 +1274,11 @@ static void smc_core_going_away(void)
 	}
 	mutex_unlock(&smc_ib_devices.mutex);
 
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_for_each_entry(smcd, &smcd_dev_list.list, list) {
 		smcd->going_away = 1;
 	}
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 }
 
 /* Clean up all SMC link groups */
@@ -1290,10 +1290,10 @@ static void smc_lgrs_shutdown(void)
 
 	smc_smcr_terminate_all(NULL);
 
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_for_each_entry(smcd, &smcd_dev_list.list, list)
 		smc_smcd_terminate_all(smcd);
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 }
 
 static int smc_core_reboot_event(struct notifier_block *this,
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 #include <asm/page.h>
 
@@ -17,7 +18,7 @@
 
 struct smcd_dev_list smcd_dev_list = {
 	.list = LIST_HEAD_INIT(smcd_dev_list.list),
-	.lock = __SPIN_LOCK_UNLOCKED(smcd_dev_list.lock)
+	.mutex = __MUTEX_INITIALIZER(smcd_dev_list.mutex)
 };
 
 /* Test if an ISM communication is possible. */
@@ -316,9 +317,9 @@ EXPORT_SYMBOL_GPL(smcd_alloc_dev);
 
 int smcd_register_dev(struct smcd_dev *smcd)
 {
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_add_tail(&smcd->list, &smcd_dev_list.list);
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 
 	return device_add(&smcd->dev);
 }
@@ -326,9 +327,9 @@ EXPORT_SYMBOL_GPL(smcd_register_dev);
 
 void smcd_unregister_dev(struct smcd_dev *smcd)
 {
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_del_init(&smcd->list);
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 	smcd->going_away = 1;
 	smc_smcd_terminate_all(smcd);
 	flush_workqueue(smcd->event_wq);
--- a/net/smc/smc_ism.h
+++ b/net/smc/smc_ism.h
@@ -10,12 +10,13 @@
 #define SMCD_ISM_H
 
 #include <linux/uio.h>
+#include <linux/mutex.h>
 
 #include "smc.h"
 
 struct smcd_dev_list {	/* List of SMCD devices */
 	struct list_head list;
-	spinlock_t lock;	/* Protects list of devices */
+	struct mutex mutex;	/* Protects list of devices */
 };
 
 extern struct smcd_dev_list	smcd_dev_list; /* list of smcd devices */
--- a/net/smc/smc_pnet.c
+++ b/net/smc/smc_pnet.c
@@ -142,7 +142,7 @@ static int smc_pnet_remove_by_pnetid(str
 	}
 	mutex_unlock(&smc_ib_devices.mutex);
 	/* remove smcd devices */
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
 		if (smcd_dev->pnetid_by_user &&
 		    (!pnet_name ||
@@ -152,7 +152,7 @@ static int smc_pnet_remove_by_pnetid(str
 			rc = 0;
 		}
 	}
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 	return rc;
 }
 
@@ -214,14 +214,14 @@ static int smc_pnet_enter(struct smc_pne
 	if (new_pnetelem->smcd_dev) {
 		struct smcd_dev *smcd_dev = new_pnetelem->smcd_dev;
 
-		spin_lock(&smcd_dev_list.lock);
+		mutex_lock(&smcd_dev_list.mutex);
 		if (smc_pnet_match(smcd_dev->pnetid, pnet_null)) {
 			memcpy(smcd_dev->pnetid, new_pnetelem->pnet_name,
 			       SMC_MAX_PNETID_LEN);
 			smcd_dev->pnetid_by_user = true;
 			new_smcddev = true;
 		}
-		spin_unlock(&smcd_dev_list.lock);
+		mutex_unlock(&smcd_dev_list.mutex);
 	}
 
 	if (!new_pnetelem->ndev)
@@ -312,7 +312,7 @@ static struct smcd_dev *smc_pnet_find_sm
 {
 	struct smcd_dev *smcd_dev;
 
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
 		if (!strncmp(dev_name(&smcd_dev->dev), smcd_name,
 			     IB_DEVICE_NAME_MAX - 1))
@@ -320,7 +320,7 @@ static struct smcd_dev *smc_pnet_find_sm
 	}
 	smcd_dev = NULL;
 out:
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 	return smcd_dev;
 }
 
@@ -535,7 +535,7 @@ static int _smc_pnet_dump(struct net *ne
 	mutex_unlock(&smc_ib_devices.mutex);
 
 	/* dump smcd devices */
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
 		if (smcd_dev->pnetid_by_user) {
 			if (pnetid && !smc_pnet_match(smcd_dev->pnetid, pnetid))
@@ -553,7 +553,7 @@ static int _smc_pnet_dump(struct net *ne
 			}
 		}
 	}
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 
 	return idx;
 }
@@ -845,7 +845,7 @@ static void smc_pnet_find_ism_by_pnetid(
 	    smc_pnet_find_ndev_pnetid_by_table(ndev, ndev_pnetid))
 		return; /* pnetid could not be determined */
 
-	spin_lock(&smcd_dev_list.lock);
+	mutex_lock(&smcd_dev_list.mutex);
 	list_for_each_entry(ismdev, &smcd_dev_list.list, list) {
 		if (smc_pnet_match(ismdev->pnetid, ndev_pnetid) &&
 		    !ismdev->going_away) {
@@ -853,7 +853,7 @@ static void smc_pnet_find_ism_by_pnetid(
 			break;
 		}
 	}
-	spin_unlock(&smcd_dev_list.lock);
+	mutex_unlock(&smcd_dev_list.mutex);
 }
 
 /* PNET table analysis for a given sock: