Skip to content

Commit

Permalink
ipv6: use RCU to walk list of network devices
Browse files Browse the repository at this point in the history 
No longer need read_lock(&dev_base_lock), use RCU instead.
We also can avoid taking references on inet6_dev structs.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
Eric Dumazet authored and David S. Miller committed Nov 14, 2009
1 parent bee7ca9 commit ce81b76
Show file tree
Hide file tree
Showing 3 changed files with 47 additions and 43 deletions.
10 changes: 10 additions & 0 deletions include/linux/netdevice.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1114,6 +1114,16 @@ static inline struct net_device *next_net_device(struct net_device *dev)
return lh == &net->dev_base_head ? NULL : net_device_entry(lh);
}

static inline struct net_device *next_net_device_rcu(struct net_device *dev)
{
struct list_head *lh;
struct net *net;

net = dev_net(dev);
lh = rcu_dereference(dev->dev_list.next);
return lh == &net->dev_base_head ? NULL : net_device_entry(lh);
}

static inline struct net_device *first_net_device(struct net *net)
{
return list_empty(&net->dev_base_head) ? NULL :
Expand Down
29 changes: 14 additions & 15 deletions net/ipv6/anycast.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -431,9 +431,9 @@ static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
struct net *net = seq_file_net(seq);

state->idev = NULL;
for_each_netdev(net, state->dev) {
for_each_netdev_rcu(net, state->dev) {
struct inet6_dev *idev;
idev = in6_dev_get(state->dev);
idev = __in6_dev_get(state->dev);
if (!idev)
continue;
read_lock_bh(&idev->lock);
Expand All @@ -443,7 +443,6 @@ static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
break;
}
read_unlock_bh(&idev->lock);
in6_dev_put(idev);
}
return im;
}
Expand All @@ -454,16 +453,15 @@ static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im

im = im->aca_next;
while (!im) {
if (likely(state->idev != NULL)) {
if (likely(state->idev != NULL))
read_unlock_bh(&state->idev->lock);
in6_dev_put(state->idev);
}
state->dev = next_net_device(state->dev);

state->dev = next_net_device_rcu(state->dev);
if (!state->dev) {
state->idev = NULL;
break;
}
state->idev = in6_dev_get(state->dev);
state->idev = __in6_dev_get(state->dev);
if (!state->idev)
continue;
read_lock_bh(&state->idev->lock);
Expand All @@ -482,29 +480,30 @@ static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
}

static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(dev_base_lock)
__acquires(RCU)
{
read_lock(&dev_base_lock);
rcu_read_lock();
return ac6_get_idx(seq, *pos);
}

static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct ifacaddr6 *im;
im = ac6_get_next(seq, v);
struct ifacaddr6 *im = ac6_get_next(seq, v);

++*pos;
return im;
}

static void ac6_seq_stop(struct seq_file *seq, void *v)
__releases(dev_base_lock)
__releases(RCU)
{
struct ac6_iter_state *state = ac6_seq_private(seq);

if (likely(state->idev != NULL)) {
read_unlock_bh(&state->idev->lock);
in6_dev_put(state->idev);
state->idev = NULL;
}
read_unlock(&dev_base_lock);
rcu_read_unlock();
}

static int ac6_seq_show(struct seq_file *seq, void *v)
Expand Down
51 changes: 23 additions & 28 deletions net/ipv6/mcast.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2375,9 +2375,9 @@ static inline struct ifmcaddr6 *igmp6_mc_get_first(struct seq_file *seq)
struct net *net = seq_file_net(seq);

state->idev = NULL;
for_each_netdev(net, state->dev) {
for_each_netdev_rcu(net, state->dev) {
struct inet6_dev *idev;
idev = in6_dev_get(state->dev);
idev = __in6_dev_get(state->dev);
if (!idev)
continue;
read_lock_bh(&idev->lock);
Expand All @@ -2387,7 +2387,6 @@ static inline struct ifmcaddr6 *igmp6_mc_get_first(struct seq_file *seq)
break;
}
read_unlock_bh(&idev->lock);
in6_dev_put(idev);
}
return im;
}
Expand All @@ -2398,16 +2397,15 @@ static struct ifmcaddr6 *igmp6_mc_get_next(struct seq_file *seq, struct ifmcaddr

im = im->next;
while (!im) {
if (likely(state->idev != NULL)) {
if (likely(state->idev != NULL))
read_unlock_bh(&state->idev->lock);
in6_dev_put(state->idev);
}
state->dev = next_net_device(state->dev);

state->dev = next_net_device_rcu(state->dev);
if (!state->dev) {
state->idev = NULL;
break;
}
state->idev = in6_dev_get(state->dev);
state->idev = __in6_dev_get(state->dev);
if (!state->idev)
continue;
read_lock_bh(&state->idev->lock);
Expand All @@ -2426,31 +2424,31 @@ static struct ifmcaddr6 *igmp6_mc_get_idx(struct seq_file *seq, loff_t pos)
}

static void *igmp6_mc_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(dev_base_lock)
__acquires(RCU)
{
read_lock(&dev_base_lock);
rcu_read_lock();
return igmp6_mc_get_idx(seq, *pos);
}

static void *igmp6_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct ifmcaddr6 *im;
im = igmp6_mc_get_next(seq, v);
struct ifmcaddr6 *im = igmp6_mc_get_next(seq, v);

++*pos;
return im;
}

static void igmp6_mc_seq_stop(struct seq_file *seq, void *v)
__releases(dev_base_lock)
__releases(RCU)
{
struct igmp6_mc_iter_state *state = igmp6_mc_seq_private(seq);

if (likely(state->idev != NULL)) {
read_unlock_bh(&state->idev->lock);
in6_dev_put(state->idev);
state->idev = NULL;
}
state->dev = NULL;
read_unlock(&dev_base_lock);
rcu_read_unlock();
}

static int igmp6_mc_seq_show(struct seq_file *seq, void *v)
Expand Down Expand Up @@ -2507,9 +2505,9 @@ static inline struct ip6_sf_list *igmp6_mcf_get_first(struct seq_file *seq)

state->idev = NULL;
state->im = NULL;
for_each_netdev(net, state->dev) {
for_each_netdev_rcu(net, state->dev) {
struct inet6_dev *idev;
idev = in6_dev_get(state->dev);
idev = __in6_dev_get(state->dev);
if (unlikely(idev == NULL))
continue;
read_lock_bh(&idev->lock);
Expand All @@ -2525,7 +2523,6 @@ static inline struct ip6_sf_list *igmp6_mcf_get_first(struct seq_file *seq)
spin_unlock_bh(&im->mca_lock);
}
read_unlock_bh(&idev->lock);
in6_dev_put(idev);
}
return psf;
}
Expand All @@ -2539,16 +2536,15 @@ static struct ip6_sf_list *igmp6_mcf_get_next(struct seq_file *seq, struct ip6_s
spin_unlock_bh(&state->im->mca_lock);
state->im = state->im->next;
while (!state->im) {
if (likely(state->idev != NULL)) {
if (likely(state->idev != NULL))
read_unlock_bh(&state->idev->lock);
in6_dev_put(state->idev);
}
state->dev = next_net_device(state->dev);

state->dev = next_net_device_rcu(state->dev);
if (!state->dev) {
state->idev = NULL;
goto out;
}
state->idev = in6_dev_get(state->dev);
state->idev = __in6_dev_get(state->dev);
if (!state->idev)
continue;
read_lock_bh(&state->idev->lock);
Expand All @@ -2573,9 +2569,9 @@ static struct ip6_sf_list *igmp6_mcf_get_idx(struct seq_file *seq, loff_t pos)
}

static void *igmp6_mcf_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(dev_base_lock)
__acquires(RCU)
{
read_lock(&dev_base_lock);
rcu_read_lock();
return *pos ? igmp6_mcf_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

Expand All @@ -2591,7 +2587,7 @@ static void *igmp6_mcf_seq_next(struct seq_file *seq, void *v, loff_t *pos)
}

static void igmp6_mcf_seq_stop(struct seq_file *seq, void *v)
__releases(dev_base_lock)
__releases(RCU)
{
struct igmp6_mcf_iter_state *state = igmp6_mcf_seq_private(seq);
if (likely(state->im != NULL)) {
Expand All @@ -2600,11 +2596,10 @@ static void igmp6_mcf_seq_stop(struct seq_file *seq, void *v)
}
if (likely(state->idev != NULL)) {
read_unlock_bh(&state->idev->lock);
in6_dev_put(state->idev);
state->idev = NULL;
}
state->dev = NULL;
read_unlock(&dev_base_lock);
rcu_read_unlock();
}

static int igmp6_mcf_seq_show(struct seq_file *seq, void *v)
Expand Down

0 comments on commit ce81b76

Please sign in to comment.