linux-kernel - [PATCH v2 2/2] cxgb4: smt: Use refcount

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Message-Id: <20190802083547.12657-1-hslester96@gmail.com>
Date:   Fri,  2 Aug 2019 16:35:47 +0800
From:   Chuhong Yuan <hslester96@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Vishal Kulkarni <vishal@...lsio.com>,
        "David S . Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Chuhong Yuan <hslester96@...il.com>
Subject: [PATCH v2 2/2] cxgb4: smt: Use refcount_t for refcount

refcount_t is better for reference counters since its
implementation can prevent overflows.
So convert atomic_t ref counters to refcount_t.

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

 drivers/net/ethernet/chelsio/cxgb4/smt.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/smt.c b/drivers/net/ethernet/chelsio/cxgb4/smt.c
index eaf1fb74689c..343887fa52aa 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/smt.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/smt.c
@@ -57,7 +57,7 @@ struct smt_data *t4_init_smt(void)
 		s->smtab[i].state = SMT_STATE_UNUSED;
 		memset(&s->smtab[i].src_mac, 0, ETH_ALEN);
 		spin_lock_init(&s->smtab[i].lock);
-		atomic_set(&s->smtab[i].refcnt, 0);
+		refcount_set(&s->smtab[i].refcnt, 1);
 	}
 	return s;
 }
@@ -68,7 +68,7 @@ static struct smt_entry *find_or_alloc_smte(struct smt_data *s, u8 *smac)
 	struct smt_entry *e, *end;
 
 	for (e = &s->smtab[0], end = &s->smtab[s->smt_size]; e != end; ++e) {
-		if (atomic_read(&e->refcnt) == 0) {
+		if (refcount_read(&e->refcnt) == 1) {
 			if (!first_free)
 				first_free = e;
 		} else {
@@ -98,7 +98,7 @@ static struct smt_entry *find_or_alloc_smte(struct smt_data *s, u8 *smac)
 static void t4_smte_free(struct smt_entry *e)
 {
 	spin_lock_bh(&e->lock);
-	if (atomic_read(&e->refcnt) == 0) {  /* hasn't been recycled */
+	if (refcount_read(&e->refcnt) == 1) {  /* hasn't been recycled */
 		e->state = SMT_STATE_UNUSED;
 	}
 	spin_unlock_bh(&e->lock);
@@ -111,7 +111,7 @@ static void t4_smte_free(struct smt_entry *e)
  */
 void cxgb4_smt_release(struct smt_entry *e)
 {
-	if (atomic_dec_and_test(&e->refcnt))
+	if (refcount_dec_and_test(&e->refcnt))
 		t4_smte_free(e);
 }
 EXPORT_SYMBOL(cxgb4_smt_release);
@@ -215,14 +215,14 @@ static struct smt_entry *t4_smt_alloc_switching(struct adapter *adap, u16 pfvf,
 	e = find_or_alloc_smte(s, smac);
 	if (e) {
 		spin_lock(&e->lock);
-		if (!atomic_read(&e->refcnt)) {
-			atomic_set(&e->refcnt, 1);
+		if (refcount_read(&e->refcnt) == 1) {
+			refcount_set(&e->refcnt, 2);
 			e->state = SMT_STATE_SWITCHING;
 			e->pfvf = pfvf;
 			memcpy(e->src_mac, smac, ETH_ALEN);
 			write_smt_entry(adap, e);
 		} else {
-			atomic_inc(&e->refcnt);
+			refcount_inc(&e->refcnt);
 		}
 		spin_unlock(&e->lock);
 	}
-- 
2.20.1