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From:   Chuhong Yuan <hslester96@gmail.com>
Cc:     "David S . Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Chuhong Yuan <hslester96@gmail.com>
Subject: [PATCH v2 2/2] cnic: Use refcount_t for refcount
Date:   Fri,  2 Aug 2019 16:05:39 +0800
Message-Id: <20190802080539.11222-1-hslester96@gmail.com>
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Sender: linux-kernel-owner@vger.kernel.org
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refcount_t is better for reference counters since its
implementation can prevent overflows.
So convert atomic_t ref counters to refcount_t.

This patch depends on the patch:
"cnic: Explicitly initialize all reference counts to 0."

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
---
Changes in v2:
  - Convert refcount from 0-base to 1-base.

 drivers/net/ethernet/broadcom/cnic.c    | 30 ++++++++++++-------------
 drivers/net/ethernet/broadcom/cnic_if.h |  6 ++---
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/cnic.c b/drivers/net/ethernet/broadcom/cnic.c
index 155599dcee76..1f59f9606b85 100644
--- a/drivers/net/ethernet/broadcom/cnic.c
+++ b/drivers/net/ethernet/broadcom/cnic.c
@@ -141,22 +141,22 @@ static int cnic_uio_close(struct uio_info *uinfo, struct inode *inode)
 
 static inline void cnic_hold(struct cnic_dev *dev)
 {
-	atomic_inc(&dev->ref_count);
+	refcount_inc(&dev->ref_count);
 }
 
 static inline void cnic_put(struct cnic_dev *dev)
 {
-	atomic_dec(&dev->ref_count);
+	refcount_dec(&dev->ref_count);
 }
 
 static inline void csk_hold(struct cnic_sock *csk)
 {
-	atomic_inc(&csk->ref_count);
+	refcount_inc(&csk->ref_count);
 }
 
 static inline void csk_put(struct cnic_sock *csk)
 {
-	atomic_dec(&csk->ref_count);
+	refcount_dec(&csk->ref_count);
 }
 
 static struct cnic_dev *cnic_from_netdev(struct net_device *netdev)
@@ -177,12 +177,12 @@ static struct cnic_dev *cnic_from_netdev(struct net_device *netdev)
 
 static inline void ulp_get(struct cnic_ulp_ops *ulp_ops)
 {
-	atomic_inc(&ulp_ops->ref_count);
+	refcount_inc(&ulp_ops->ref_count);
 }
 
 static inline void ulp_put(struct cnic_ulp_ops *ulp_ops)
 {
-	atomic_dec(&ulp_ops->ref_count);
+	refcount_dec(&ulp_ops->ref_count);
 }
 
 static void cnic_ctx_wr(struct cnic_dev *dev, u32 cid_addr, u32 off, u32 val)
@@ -494,7 +494,7 @@ int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops)
 	}
 	read_unlock(&cnic_dev_lock);
 
-	atomic_set(&ulp_ops->ref_count, 0);
+	refcount_set(&ulp_ops->ref_count, 1);
 	rcu_assign_pointer(cnic_ulp_tbl[ulp_type], ulp_ops);
 	mutex_unlock(&cnic_lock);
 
@@ -545,12 +545,12 @@ int cnic_unregister_driver(int ulp_type)
 
 	mutex_unlock(&cnic_lock);
 	synchronize_rcu();
-	while ((atomic_read(&ulp_ops->ref_count) != 0) && (i < 20)) {
+	while ((refcount_read(&ulp_ops->ref_count) != 1) && (i < 20)) {
 		msleep(100);
 		i++;
 	}
 
-	if (atomic_read(&ulp_ops->ref_count) != 0)
+	if (refcount_read(&ulp_ops->ref_count) != 1)
 		pr_warn("%s: Failed waiting for ref count to go to zero\n",
 			__func__);
 	return 0;
@@ -3596,7 +3596,7 @@ static int cnic_cm_create(struct cnic_dev *dev, int ulp_type, u32 cid,
 	}
 
 	csk1 = &cp->csk_tbl[l5_cid];
-	if (atomic_read(&csk1->ref_count))
+	if (refcount_read(&csk1->ref_count) != 1)
 		return -EAGAIN;
 
 	if (test_and_set_bit(SK_F_INUSE, &csk1->flags))
@@ -3651,7 +3651,7 @@ static int cnic_cm_destroy(struct cnic_sock *csk)
 	csk_hold(csk);
 	clear_bit(SK_F_INUSE, &csk->flags);
 	smp_mb__after_atomic();
-	while (atomic_read(&csk->ref_count) != 1)
+	while (refcount_read(&csk->ref_count) != 2)
 		msleep(1);
 	cnic_cm_cleanup(csk);
 
@@ -4104,7 +4104,7 @@ static int cnic_cm_alloc_mem(struct cnic_dev *dev)
 		return -ENOMEM;
 
 	for (i = 0; i < MAX_CM_SK_TBL_SZ; i++)
-		atomic_set(&cp->csk_tbl[i].ref_count, 0);
+		refcount_set(&cp->csk_tbl[i].ref_count, 1);
 
 	port_id = prandom_u32();
 	port_id %= CNIC_LOCAL_PORT_RANGE;
@@ -5436,11 +5436,11 @@ static void cnic_free_dev(struct cnic_dev *dev)
 {
 	int i = 0;
 
-	while ((atomic_read(&dev->ref_count) != 0) && i < 10) {
+	while ((refcount_read(&dev->ref_count) != 1) && i < 10) {
 		msleep(100);
 		i++;
 	}
-	if (atomic_read(&dev->ref_count) != 0)
+	if (refcount_read(&dev->ref_count) != 1)
 		netdev_err(dev->netdev, "Failed waiting for ref count to go to zero\n");
 
 	netdev_info(dev->netdev, "Removed CNIC device\n");
@@ -5484,7 +5484,7 @@ static struct cnic_dev *cnic_alloc_dev(struct net_device *dev,
 	cdev->unregister_device = cnic_unregister_device;
 	cdev->iscsi_nl_msg_recv = cnic_iscsi_nl_msg_recv;
 	cdev->get_fc_npiv_tbl = cnic_get_fc_npiv_tbl;
-	atomic_set(&cdev->ref_count, 0);
+	refcount_set(&cdev->ref_count, 1);
 
 	cp = cdev->cnic_priv;
 	cp->dev = cdev;
diff --git a/drivers/net/ethernet/broadcom/cnic_if.h b/drivers/net/ethernet/broadcom/cnic_if.h
index 789e5c7e9311..5232a05ac7ba 100644
--- a/drivers/net/ethernet/broadcom/cnic_if.h
+++ b/drivers/net/ethernet/broadcom/cnic_if.h
@@ -300,7 +300,7 @@ struct cnic_sock {
 #define SK_F_CLOSING		7
 #define SK_F_HW_ERR		8
 
-	atomic_t ref_count;
+	refcount_t ref_count;
 	u32 state;
 	struct kwqe kwqe1;
 	struct kwqe kwqe2;
@@ -335,7 +335,7 @@ struct cnic_dev {
 #define CNIC_F_CNIC_UP		1
 #define CNIC_F_BNX2_CLASS	3
 #define CNIC_F_BNX2X_CLASS	4
-	atomic_t	ref_count;
+	refcount_t	ref_count;
 	u8		mac_addr[ETH_ALEN];
 
 	int		max_iscsi_conn;
@@ -378,7 +378,7 @@ struct cnic_ulp_ops {
 				  char *data, u16 data_size);
 	int (*cnic_get_stats)(void *ulp_ctx);
 	struct module *owner;
-	atomic_t ref_count;
+	refcount_t ref_count;
 };
 
 int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops);
-- 
2.20.1