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Date: Sat, 17 Jul 2021 18:16:54 +0800
From: Xiyu Yang <xiyuyang19@...an.edu.cn>
To: Raju Rangoju <rajur@...lsio.com>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: yuanxzhang@...an.edu.cn, Xiyu Yang <xiyuyang19@...an.edu.cn>,
Xin Tan <tanxin.ctf@...il.com>
Subject: [PATCH] cxgb4: Convert from atomic_t to refcount_t on l2t_entry->refcnt
refcount_t type and corresponding API can protect refcounters from
accidental underflow and overflow and further use-after-free situations.
Signed-off-by: Xiyu Yang <xiyuyang19@...an.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@...il.com>
---
drivers/net/ethernet/chelsio/cxgb4/l2t.c | 31 ++++++++++++++++---------------
drivers/net/ethernet/chelsio/cxgb4/l2t.h | 3 ++-
2 files changed, 18 insertions(+), 16 deletions(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb4/l2t.c b/drivers/net/ethernet/chelsio/cxgb4/l2t.c
index a10a6862a9a4..cb26a5e315b1 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/l2t.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/l2t.c
@@ -69,7 +69,8 @@ static inline unsigned int vlan_prio(const struct l2t_entry *e)
static inline void l2t_hold(struct l2t_data *d, struct l2t_entry *e)
{
- if (atomic_add_return(1, &e->refcnt) == 1) /* 0 -> 1 transition */
+ refcount_inc(&e->refcnt);
+ if (refcount_read(&e->refcnt) == 1) /* 0 -> 1 transition */
atomic_dec(&d->nfree);
}
@@ -270,10 +271,10 @@ static struct l2t_entry *alloc_l2e(struct l2t_data *d)
/* there's definitely a free entry */
for (e = d->rover, end = &d->l2tab[d->l2t_size]; e != end; ++e)
- if (atomic_read(&e->refcnt) == 0)
+ if (refcount_read(&e->refcnt) == 0)
goto found;
- for (e = d->l2tab; atomic_read(&e->refcnt); ++e)
+ for (e = d->l2tab; refcount_read(&e->refcnt); ++e)
;
found:
d->rover = e + 1;
@@ -302,7 +303,7 @@ static struct l2t_entry *find_or_alloc_l2e(struct l2t_data *d, u16 vlan,
struct l2t_entry *first_free = NULL;
for (e = &d->l2tab[0], end = &d->l2tab[d->l2t_size]; e != end; ++e) {
- if (atomic_read(&e->refcnt) == 0) {
+ if (refcount_read(&e->refcnt) == 0) {
if (!first_free)
first_free = e;
} else {
@@ -352,7 +353,7 @@ static void _t4_l2e_free(struct l2t_entry *e)
{
struct l2t_data *d;
- if (atomic_read(&e->refcnt) == 0) { /* hasn't been recycled */
+ if (refcount_read(&e->refcnt) == 0) { /* hasn't been recycled */
if (e->neigh) {
neigh_release(e->neigh);
e->neigh = NULL;
@@ -370,7 +371,7 @@ static void t4_l2e_free(struct l2t_entry *e)
struct l2t_data *d;
spin_lock_bh(&e->lock);
- if (atomic_read(&e->refcnt) == 0) { /* hasn't been recycled */
+ if (refcount_read(&e->refcnt) == 0) { /* hasn't been recycled */
if (e->neigh) {
neigh_release(e->neigh);
e->neigh = NULL;
@@ -385,7 +386,7 @@ static void t4_l2e_free(struct l2t_entry *e)
void cxgb4_l2t_release(struct l2t_entry *e)
{
- if (atomic_dec_and_test(&e->refcnt))
+ if (refcount_dec_and_test(&e->refcnt))
t4_l2e_free(e);
}
EXPORT_SYMBOL(cxgb4_l2t_release);
@@ -441,7 +442,7 @@ struct l2t_entry *cxgb4_l2t_get(struct l2t_data *d, struct neighbour *neigh,
if (!addreq(e, addr) && e->ifindex == ifidx &&
e->vlan == vlan && e->lport == lport) {
l2t_hold(d, e);
- if (atomic_read(&e->refcnt) == 1)
+ if (refcount_read(&e->refcnt) == 1)
reuse_entry(e, neigh);
goto done;
}
@@ -458,7 +459,7 @@ struct l2t_entry *cxgb4_l2t_get(struct l2t_data *d, struct neighbour *neigh,
e->hash = hash;
e->lport = lport;
e->v6 = addr_len == 16;
- atomic_set(&e->refcnt, 1);
+ refcount_set(&e->refcnt, 1);
neigh_replace(e, neigh);
e->vlan = vlan;
e->next = d->l2tab[hash].first;
@@ -520,7 +521,7 @@ void t4_l2t_update(struct adapter *adap, struct neighbour *neigh)
for (e = d->l2tab[hash].first; e; e = e->next)
if (!addreq(e, addr) && e->ifindex == ifidx) {
spin_lock(&e->lock);
- if (atomic_read(&e->refcnt))
+ if (refcount_read(&e->refcnt))
goto found;
spin_unlock(&e->lock);
break;
@@ -585,12 +586,12 @@ struct l2t_entry *t4_l2t_alloc_switching(struct adapter *adap, u16 vlan,
e = find_or_alloc_l2e(d, vlan, port, eth_addr);
if (e) {
spin_lock(&e->lock); /* avoid race with t4_l2t_free */
- if (!atomic_read(&e->refcnt)) {
+ if (!refcount_read(&e->refcnt)) {
e->state = L2T_STATE_SWITCHING;
e->vlan = vlan;
e->lport = port;
ether_addr_copy(e->dmac, eth_addr);
- atomic_set(&e->refcnt, 1);
+ refcount_set(&e->refcnt, 1);
ret = write_l2e(adap, e, 0);
if (ret < 0) {
_t4_l2e_free(e);
@@ -599,7 +600,7 @@ struct l2t_entry *t4_l2t_alloc_switching(struct adapter *adap, u16 vlan,
return NULL;
}
} else {
- atomic_inc(&e->refcnt);
+ refcount_inc(&e->refcnt);
}
spin_unlock(&e->lock);
@@ -654,7 +655,7 @@ struct l2t_data *t4_init_l2t(unsigned int l2t_start, unsigned int l2t_end)
d->l2tab[i].idx = i;
d->l2tab[i].state = L2T_STATE_UNUSED;
spin_lock_init(&d->l2tab[i].lock);
- atomic_set(&d->l2tab[i].refcnt, 0);
+ refcount_set(&d->l2tab[i].refcnt, 0);
skb_queue_head_init(&d->l2tab[i].arpq);
}
return d;
@@ -726,7 +727,7 @@ static int l2t_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "%4u %-25s %17pM %4d %u %2u %c %5u %s\n",
e->idx + d->l2t_start, ip, e->dmac,
e->vlan & VLAN_VID_MASK, vlan_prio(e), e->lport,
- l2e_state(e), atomic_read(&e->refcnt),
+ l2e_state(e), refcount_read(&e->refcnt),
e->neigh ? e->neigh->dev->name : "");
spin_unlock_bh(&e->lock);
}
diff --git a/drivers/net/ethernet/chelsio/cxgb4/l2t.h b/drivers/net/ethernet/chelsio/cxgb4/l2t.h
index 340fecb28a13..6914a0e9836b 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/l2t.h
+++ b/drivers/net/ethernet/chelsio/cxgb4/l2t.h
@@ -38,6 +38,7 @@
#include <linux/spinlock.h>
#include <linux/if_ether.h>
#include <linux/atomic.h>
+#include <linux/refcount.h>
#define VLAN_NONE 0xfff
@@ -80,7 +81,7 @@ struct l2t_entry {
struct l2t_entry *next; /* next l2t_entry on chain */
struct sk_buff_head arpq; /* packet queue awaiting resolution */
spinlock_t lock;
- atomic_t refcnt; /* entry reference count */
+ refcount_t refcnt; /* entry reference count */
u16 hash; /* hash bucket the entry is on */
u16 vlan; /* VLAN TCI (id: bits 0-11, prio: 13-15 */
u8 v6; /* whether entry is for IPv6 */
--
2.7.4
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