| Message ID | 660872d4d795833eca5f7e517c7e1dabbc1df02b.1433350421.git.marcelo.leitner@gmail.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, Jun 03, 2015 at 01:54:01PM -0300, mleitner@redhat.com wrote: > From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > > That's needed for the next patch, so we break the lock inversion between > netns_sctp->addr_wq_lock and socket lock on > sctp_addr_wq_timeout_handler(). With this, we can traverse addr_waitq > without taking addr_wq_lock, taking it just for the write operations. > > Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > --- > > Notes: > v1->v2: > As asked by Neil, this now reuses addr_wq_lock. And for that, also > rcu-ifyies addr_waitq. > > include/net/netns/sctp.h | 2 +- > net/sctp/protocol.c | 81 +++++++++++++++++++++++++++++------------------- > 2 files changed, 50 insertions(+), 33 deletions(-) > > diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h > index 3573a81815ad9e0efb6ceb721eb066d3726419f0..9e53412c4ed829e8e45777a6d95406d490dbaa75 100644 > --- a/include/net/netns/sctp.h > +++ b/include/net/netns/sctp.h > @@ -28,7 +28,7 @@ struct netns_sctp { > * It is a list of sctp_sockaddr_entry. > */ > struct list_head local_addr_list; > - struct list_head addr_waitq; > + struct list_head __rcu addr_waitq; > struct timer_list addr_wq_timer; > struct list_head auto_asconf_splist; > spinlock_t addr_wq_lock; > diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c > index 53b7acde9aa37bf3d4029c459421564d5270f4c0..a5089883b28195f3aef69ef35b5397322a01126f 100644 > --- a/net/sctp/protocol.c > +++ b/net/sctp/protocol.c > @@ -593,15 +593,46 @@ static void sctp_v4_ecn_capable(struct sock *sk) > INET_ECN_xmit(sk); > } > > +static void sctp_free_addr_wq(struct net *net) > +{ > + struct sctp_sockaddr_entry *addrw; > + > + spin_lock_bh(&net->sctp.addr_wq_lock); > + del_timer(&net->sctp.addr_wq_timer); > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > + list_del_rcu(&addrw->list); > + kfree_rcu(addrw, rcu); > + } > + spin_unlock_bh(&net->sctp.addr_wq_lock); > +} > + > +/* As there is no refcnt on sctp_sockaddr_entry, we must check inside > + * the lock if it wasn't removed from addr_waitq already, otherwise we > + * could double-free it. > + */ > +static void sctp_free_addr_wq_entry(struct net *net, > + struct sctp_sockaddr_entry *addrw) > +{ > + struct sctp_sockaddr_entry *temp; > + > + spin_lock_bh(&net->sctp.addr_wq_lock); > + list_for_each_entry_rcu(temp, &net->sctp.addr_waitq, list) { > + if (temp == addrw) { > + list_del_rcu(&addrw->list); > + kfree_rcu(addrw, rcu); Missed a break here, will issue a v3 when you review it too.. Marcelo > + } > + } > + spin_unlock_bh(&net->sctp.addr_wq_lock); > +} > + > static void sctp_addr_wq_timeout_handler(unsigned long arg) > { > struct net *net = (struct net *)arg; > - struct sctp_sockaddr_entry *addrw, *temp; > + struct sctp_sockaddr_entry *addrw; > struct sctp_sock *sp; > > - spin_lock_bh(&net->sctp.addr_wq_lock); > - > - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { > + rcu_read_lock_bh(); > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at " > "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa, > addrw->state, addrw); > @@ -627,7 +658,9 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) > > timeo_val = jiffies; > timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY); > + spin_lock_bh(&net->sctp.addr_wq_lock); > mod_timer(&net->sctp.addr_wq_timer, timeo_val); > + spin_unlock_bh(&net->sctp.addr_wq_lock); > break; > } > } > @@ -647,35 +680,20 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) > #if IS_ENABLED(CONFIG_IPV6) > free_next: > #endif > - list_del(&addrw->list); > - kfree(addrw); > - } > - spin_unlock_bh(&net->sctp.addr_wq_lock); > -} > - > -static void sctp_free_addr_wq(struct net *net) > -{ > - struct sctp_sockaddr_entry *addrw; > - struct sctp_sockaddr_entry *temp; > - > - spin_lock_bh(&net->sctp.addr_wq_lock); > - del_timer(&net->sctp.addr_wq_timer); > - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { > - list_del(&addrw->list); > - kfree(addrw); > + sctp_free_addr_wq_entry(net, addrw); > } > - spin_unlock_bh(&net->sctp.addr_wq_lock); > + rcu_read_unlock_bh(); > } > > /* lookup the entry for the same address in the addr_waitq > - * sctp_addr_wq MUST be locked > + * rcu read MUST be locked > */ > static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net, > struct sctp_sockaddr_entry *addr) > { > struct sctp_sockaddr_entry *addrw; > > - list_for_each_entry(addrw, &net->sctp.addr_waitq, list) { > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > if (addrw->a.sa.sa_family != addr->a.sa.sa_family) > continue; > if (addrw->a.sa.sa_family == AF_INET) { > @@ -702,7 +720,7 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm > * new address after a couple of addition and deletion of that address > */ > > - spin_lock_bh(&net->sctp.addr_wq_lock); > + rcu_read_lock_bh(); > /* Offsets existing events in addr_wq */ > addrw = sctp_addr_wq_lookup(net, addr); > if (addrw) { > @@ -710,22 +728,21 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm > pr_debug("%s: offsets existing entry for %d, addr:%pISc " > "in wq:%p\n", __func__, addrw->state, &addrw->a.sa, > &net->sctp.addr_waitq); > - > - list_del(&addrw->list); > - kfree(addrw); > + sctp_free_addr_wq_entry(net, addrw); > } > - spin_unlock_bh(&net->sctp.addr_wq_lock); > + rcu_read_unlock_bh(); > return; > } > + rcu_read_unlock_bh(); > > /* OK, we have to add the new address to the wait queue */ > addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC); > - if (addrw == NULL) { > - spin_unlock_bh(&net->sctp.addr_wq_lock); > + if (!addrw) > return; > - } > addrw->state = cmd; > - list_add_tail(&addrw->list, &net->sctp.addr_waitq); > + > + spin_lock_bh(&net->sctp.addr_wq_lock); > + list_add_tail_rcu(&addrw->list, &net->sctp.addr_waitq); > > pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n", > __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq); > -- > 2.4.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jun 03, 2015 at 01:54:01PM -0300, mleitner@redhat.com wrote: > From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > > That's needed for the next patch, so we break the lock inversion between > netns_sctp->addr_wq_lock and socket lock on > sctp_addr_wq_timeout_handler(). With this, we can traverse addr_waitq > without taking addr_wq_lock, taking it just for the write operations. > > Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > --- > > Notes: > v1->v2: > As asked by Neil, this now reuses addr_wq_lock. And for that, also > rcu-ifyies addr_waitq. > > include/net/netns/sctp.h | 2 +- > net/sctp/protocol.c | 81 +++++++++++++++++++++++++++++------------------- > 2 files changed, 50 insertions(+), 33 deletions(-) > > diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h > index 3573a81815ad9e0efb6ceb721eb066d3726419f0..9e53412c4ed829e8e45777a6d95406d490dbaa75 100644 > --- a/include/net/netns/sctp.h > +++ b/include/net/netns/sctp.h > @@ -28,7 +28,7 @@ struct netns_sctp { > * It is a list of sctp_sockaddr_entry. > */ > struct list_head local_addr_list; > - struct list_head addr_waitq; > + struct list_head __rcu addr_waitq; > struct timer_list addr_wq_timer; > struct list_head auto_asconf_splist; > spinlock_t addr_wq_lock; > diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c > index 53b7acde9aa37bf3d4029c459421564d5270f4c0..a5089883b28195f3aef69ef35b5397322a01126f 100644 > --- a/net/sctp/protocol.c > +++ b/net/sctp/protocol.c > @@ -593,15 +593,46 @@ static void sctp_v4_ecn_capable(struct sock *sk) > INET_ECN_xmit(sk); > } > > +static void sctp_free_addr_wq(struct net *net) > +{ > + struct sctp_sockaddr_entry *addrw; > + > + spin_lock_bh(&net->sctp.addr_wq_lock); > + del_timer(&net->sctp.addr_wq_timer); > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > + list_del_rcu(&addrw->list); > + kfree_rcu(addrw, rcu); > + } > + spin_unlock_bh(&net->sctp.addr_wq_lock); > +} > + > +/* As there is no refcnt on sctp_sockaddr_entry, we must check inside > + * the lock if it wasn't removed from addr_waitq already, otherwise we > + * could double-free it. > + */ > +static void sctp_free_addr_wq_entry(struct net *net, > + struct sctp_sockaddr_entry *addrw) > +{ > + struct sctp_sockaddr_entry *temp; > + > + spin_lock_bh(&net->sctp.addr_wq_lock); > + list_for_each_entry_rcu(temp, &net->sctp.addr_waitq, list) { > + if (temp == addrw) { > + list_del_rcu(&addrw->list); > + kfree_rcu(addrw, rcu); > + } > + } > + spin_unlock_bh(&net->sctp.addr_wq_lock); > +} > + > static void sctp_addr_wq_timeout_handler(unsigned long arg) > { > struct net *net = (struct net *)arg; > - struct sctp_sockaddr_entry *addrw, *temp; > + struct sctp_sockaddr_entry *addrw; > struct sctp_sock *sp; > > - spin_lock_bh(&net->sctp.addr_wq_lock); > - > - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { > + rcu_read_lock_bh(); > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at " > "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa, > addrw->state, addrw); > @@ -627,7 +658,9 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) > > timeo_val = jiffies; > timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY); > + spin_lock_bh(&net->sctp.addr_wq_lock); > mod_timer(&net->sctp.addr_wq_timer, timeo_val); > + spin_unlock_bh(&net->sctp.addr_wq_lock); Do we actually need to lock the addr_wq_lock here? mod_timer has its own internal locking. > break; > } > } > @@ -647,35 +680,20 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) > #if IS_ENABLED(CONFIG_IPV6) > free_next: > #endif > - list_del(&addrw->list); > - kfree(addrw); > - } > - spin_unlock_bh(&net->sctp.addr_wq_lock); > -} > - > -static void sctp_free_addr_wq(struct net *net) > -{ > - struct sctp_sockaddr_entry *addrw; > - struct sctp_sockaddr_entry *temp; > - > - spin_lock_bh(&net->sctp.addr_wq_lock); > - del_timer(&net->sctp.addr_wq_timer); > - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { > - list_del(&addrw->list); > - kfree(addrw); > + sctp_free_addr_wq_entry(net, addrw); > } > - spin_unlock_bh(&net->sctp.addr_wq_lock); > + rcu_read_unlock_bh(); > } > > /* lookup the entry for the same address in the addr_waitq > - * sctp_addr_wq MUST be locked > + * rcu read MUST be locked > */ > static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net, > struct sctp_sockaddr_entry *addr) > { > struct sctp_sockaddr_entry *addrw; > > - list_for_each_entry(addrw, &net->sctp.addr_waitq, list) { > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > if (addrw->a.sa.sa_family != addr->a.sa.sa_family) > continue; > if (addrw->a.sa.sa_family == AF_INET) { > @@ -702,7 +720,7 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm > * new address after a couple of addition and deletion of that address > */ > > - spin_lock_bh(&net->sctp.addr_wq_lock); > + rcu_read_lock_bh(); > /* Offsets existing events in addr_wq */ > addrw = sctp_addr_wq_lookup(net, addr); > if (addrw) { > @@ -710,22 +728,21 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm > pr_debug("%s: offsets existing entry for %d, addr:%pISc " > "in wq:%p\n", __func__, addrw->state, &addrw->a.sa, > &net->sctp.addr_waitq); > - > - list_del(&addrw->list); > - kfree(addrw); > + sctp_free_addr_wq_entry(net, addrw); > } > - spin_unlock_bh(&net->sctp.addr_wq_lock); > + rcu_read_unlock_bh(); > return; > } > + rcu_read_unlock_bh(); > > /* OK, we have to add the new address to the wait queue */ > addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC); > - if (addrw == NULL) { > - spin_unlock_bh(&net->sctp.addr_wq_lock); > + if (!addrw) > return; > - } > addrw->state = cmd; > - list_add_tail(&addrw->list, &net->sctp.addr_waitq); > + > + spin_lock_bh(&net->sctp.addr_wq_lock); > + list_add_tail_rcu(&addrw->list, &net->sctp.addr_waitq); > > pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n", > __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq); Other than the comment above, and the break you need to insert, I think this looks good, thanks for taking the extra time on it! Best Neil > -- > 2.4.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jun 04, 2015 at 10:27:10AM -0400, Neil Horman wrote: > On Wed, Jun 03, 2015 at 01:54:01PM -0300, mleitner@redhat.com wrote: > > From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > > > > That's needed for the next patch, so we break the lock inversion between > > netns_sctp->addr_wq_lock and socket lock on > > sctp_addr_wq_timeout_handler(). With this, we can traverse addr_waitq > > without taking addr_wq_lock, taking it just for the write operations. > > > > Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > > --- > > > > Notes: > > v1->v2: > > As asked by Neil, this now reuses addr_wq_lock. And for that, also > > rcu-ifyies addr_waitq. > > > > include/net/netns/sctp.h | 2 +- > > net/sctp/protocol.c | 81 +++++++++++++++++++++++++++++------------------- > > 2 files changed, 50 insertions(+), 33 deletions(-) > > > > diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h > > index 3573a81815ad9e0efb6ceb721eb066d3726419f0..9e53412c4ed829e8e45777a6d95406d490dbaa75 100644 > > --- a/include/net/netns/sctp.h > > +++ b/include/net/netns/sctp.h > > @@ -28,7 +28,7 @@ struct netns_sctp { > > * It is a list of sctp_sockaddr_entry. > > */ > > struct list_head local_addr_list; > > - struct list_head addr_waitq; > > + struct list_head __rcu addr_waitq; > > struct timer_list addr_wq_timer; > > struct list_head auto_asconf_splist; > > spinlock_t addr_wq_lock; > > diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c > > index 53b7acde9aa37bf3d4029c459421564d5270f4c0..a5089883b28195f3aef69ef35b5397322a01126f 100644 > > --- a/net/sctp/protocol.c > > +++ b/net/sctp/protocol.c > > @@ -593,15 +593,46 @@ static void sctp_v4_ecn_capable(struct sock *sk) > > INET_ECN_xmit(sk); > > } > > > > +static void sctp_free_addr_wq(struct net *net) > > +{ > > + struct sctp_sockaddr_entry *addrw; > > + > > + spin_lock_bh(&net->sctp.addr_wq_lock); > > + del_timer(&net->sctp.addr_wq_timer); > > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > > + list_del_rcu(&addrw->list); > > + kfree_rcu(addrw, rcu); > > + } > > + spin_unlock_bh(&net->sctp.addr_wq_lock); > > +} > > + > > +/* As there is no refcnt on sctp_sockaddr_entry, we must check inside > > + * the lock if it wasn't removed from addr_waitq already, otherwise we > > + * could double-free it. > > + */ > > +static void sctp_free_addr_wq_entry(struct net *net, > > + struct sctp_sockaddr_entry *addrw) > > +{ > > + struct sctp_sockaddr_entry *temp; > > + > > + spin_lock_bh(&net->sctp.addr_wq_lock); > > + list_for_each_entry_rcu(temp, &net->sctp.addr_waitq, list) { > > + if (temp == addrw) { > > + list_del_rcu(&addrw->list); > > + kfree_rcu(addrw, rcu); > > + } > > + } > > + spin_unlock_bh(&net->sctp.addr_wq_lock); > > +} > > + > > static void sctp_addr_wq_timeout_handler(unsigned long arg) > > { > > struct net *net = (struct net *)arg; > > - struct sctp_sockaddr_entry *addrw, *temp; > > + struct sctp_sockaddr_entry *addrw; > > struct sctp_sock *sp; > > > > - spin_lock_bh(&net->sctp.addr_wq_lock); > > - > > - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { > > + rcu_read_lock_bh(); > > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > > pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at " > > "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa, > > addrw->state, addrw); > > @@ -627,7 +658,9 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) > > > > timeo_val = jiffies; > > timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY); > > + spin_lock_bh(&net->sctp.addr_wq_lock); > > mod_timer(&net->sctp.addr_wq_timer, timeo_val); > > + spin_unlock_bh(&net->sctp.addr_wq_lock); > Do we actually need to lock the addr_wq_lock here? mod_timer has its own > internal locking. No, we don't. I'll remove these. > > break; > > } > > } > > @@ -647,35 +680,20 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) > > #if IS_ENABLED(CONFIG_IPV6) > > free_next: > > #endif > > - list_del(&addrw->list); > > - kfree(addrw); > > - } > > - spin_unlock_bh(&net->sctp.addr_wq_lock); > > -} > > - > > -static void sctp_free_addr_wq(struct net *net) > > -{ > > - struct sctp_sockaddr_entry *addrw; > > - struct sctp_sockaddr_entry *temp; > > - > > - spin_lock_bh(&net->sctp.addr_wq_lock); > > - del_timer(&net->sctp.addr_wq_timer); > > - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { > > - list_del(&addrw->list); > > - kfree(addrw); > > + sctp_free_addr_wq_entry(net, addrw); > > } > > - spin_unlock_bh(&net->sctp.addr_wq_lock); > > + rcu_read_unlock_bh(); > > } > > > > /* lookup the entry for the same address in the addr_waitq > > - * sctp_addr_wq MUST be locked > > + * rcu read MUST be locked > > */ > > static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net, > > struct sctp_sockaddr_entry *addr) > > { > > struct sctp_sockaddr_entry *addrw; > > > > - list_for_each_entry(addrw, &net->sctp.addr_waitq, list) { > > + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { > > if (addrw->a.sa.sa_family != addr->a.sa.sa_family) > > continue; > > if (addrw->a.sa.sa_family == AF_INET) { > > @@ -702,7 +720,7 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm > > * new address after a couple of addition and deletion of that address > > */ > > > > - spin_lock_bh(&net->sctp.addr_wq_lock); > > + rcu_read_lock_bh(); > > /* Offsets existing events in addr_wq */ > > addrw = sctp_addr_wq_lookup(net, addr); > > if (addrw) { > > @@ -710,22 +728,21 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm > > pr_debug("%s: offsets existing entry for %d, addr:%pISc " > > "in wq:%p\n", __func__, addrw->state, &addrw->a.sa, > > &net->sctp.addr_waitq); > > - > > - list_del(&addrw->list); > > - kfree(addrw); > > + sctp_free_addr_wq_entry(net, addrw); > > } > > - spin_unlock_bh(&net->sctp.addr_wq_lock); > > + rcu_read_unlock_bh(); > > return; > > } > > + rcu_read_unlock_bh(); > > > > /* OK, we have to add the new address to the wait queue */ > > addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC); > > - if (addrw == NULL) { > > - spin_unlock_bh(&net->sctp.addr_wq_lock); > > + if (!addrw) > > return; > > - } > > addrw->state = cmd; > > - list_add_tail(&addrw->list, &net->sctp.addr_waitq); > > + > > + spin_lock_bh(&net->sctp.addr_wq_lock); > > + list_add_tail_rcu(&addrw->list, &net->sctp.addr_waitq); > > > > pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n", > > __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq); > > Other than the comment above, and the break you need to insert, I think this > looks good, thanks for taking the extra time on it! > Best > Neil Cool, thx! v3 in a few. Marcelo -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h index 3573a81815ad9e0efb6ceb721eb066d3726419f0..9e53412c4ed829e8e45777a6d95406d490dbaa75 100644 --- a/include/net/netns/sctp.h +++ b/include/net/netns/sctp.h @@ -28,7 +28,7 @@ struct netns_sctp { * It is a list of sctp_sockaddr_entry. */ struct list_head local_addr_list; - struct list_head addr_waitq; + struct list_head __rcu addr_waitq; struct timer_list addr_wq_timer; struct list_head auto_asconf_splist; spinlock_t addr_wq_lock; diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index 53b7acde9aa37bf3d4029c459421564d5270f4c0..a5089883b28195f3aef69ef35b5397322a01126f 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -593,15 +593,46 @@ static void sctp_v4_ecn_capable(struct sock *sk) INET_ECN_xmit(sk); } +static void sctp_free_addr_wq(struct net *net) +{ + struct sctp_sockaddr_entry *addrw; + + spin_lock_bh(&net->sctp.addr_wq_lock); + del_timer(&net->sctp.addr_wq_timer); + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { + list_del_rcu(&addrw->list); + kfree_rcu(addrw, rcu); + } + spin_unlock_bh(&net->sctp.addr_wq_lock); +} + +/* As there is no refcnt on sctp_sockaddr_entry, we must check inside + * the lock if it wasn't removed from addr_waitq already, otherwise we + * could double-free it. + */ +static void sctp_free_addr_wq_entry(struct net *net, + struct sctp_sockaddr_entry *addrw) +{ + struct sctp_sockaddr_entry *temp; + + spin_lock_bh(&net->sctp.addr_wq_lock); + list_for_each_entry_rcu(temp, &net->sctp.addr_waitq, list) { + if (temp == addrw) { + list_del_rcu(&addrw->list); + kfree_rcu(addrw, rcu); + } + } + spin_unlock_bh(&net->sctp.addr_wq_lock); +} + static void sctp_addr_wq_timeout_handler(unsigned long arg) { struct net *net = (struct net *)arg; - struct sctp_sockaddr_entry *addrw, *temp; + struct sctp_sockaddr_entry *addrw; struct sctp_sock *sp; - spin_lock_bh(&net->sctp.addr_wq_lock); - - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { + rcu_read_lock_bh(); + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at " "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa, addrw->state, addrw); @@ -627,7 +658,9 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) timeo_val = jiffies; timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY); + spin_lock_bh(&net->sctp.addr_wq_lock); mod_timer(&net->sctp.addr_wq_timer, timeo_val); + spin_unlock_bh(&net->sctp.addr_wq_lock); break; } } @@ -647,35 +680,20 @@ static void sctp_addr_wq_timeout_handler(unsigned long arg) #if IS_ENABLED(CONFIG_IPV6) free_next: #endif - list_del(&addrw->list); - kfree(addrw); - } - spin_unlock_bh(&net->sctp.addr_wq_lock); -} - -static void sctp_free_addr_wq(struct net *net) -{ - struct sctp_sockaddr_entry *addrw; - struct sctp_sockaddr_entry *temp; - - spin_lock_bh(&net->sctp.addr_wq_lock); - del_timer(&net->sctp.addr_wq_timer); - list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) { - list_del(&addrw->list); - kfree(addrw); + sctp_free_addr_wq_entry(net, addrw); } - spin_unlock_bh(&net->sctp.addr_wq_lock); + rcu_read_unlock_bh(); } /* lookup the entry for the same address in the addr_waitq - * sctp_addr_wq MUST be locked + * rcu read MUST be locked */ static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net, struct sctp_sockaddr_entry *addr) { struct sctp_sockaddr_entry *addrw; - list_for_each_entry(addrw, &net->sctp.addr_waitq, list) { + list_for_each_entry_rcu(addrw, &net->sctp.addr_waitq, list) { if (addrw->a.sa.sa_family != addr->a.sa.sa_family) continue; if (addrw->a.sa.sa_family == AF_INET) { @@ -702,7 +720,7 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm * new address after a couple of addition and deletion of that address */ - spin_lock_bh(&net->sctp.addr_wq_lock); + rcu_read_lock_bh(); /* Offsets existing events in addr_wq */ addrw = sctp_addr_wq_lookup(net, addr); if (addrw) { @@ -710,22 +728,21 @@ void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cm pr_debug("%s: offsets existing entry for %d, addr:%pISc " "in wq:%p\n", __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq); - - list_del(&addrw->list); - kfree(addrw); + sctp_free_addr_wq_entry(net, addrw); } - spin_unlock_bh(&net->sctp.addr_wq_lock); + rcu_read_unlock_bh(); return; } + rcu_read_unlock_bh(); /* OK, we have to add the new address to the wait queue */ addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC); - if (addrw == NULL) { - spin_unlock_bh(&net->sctp.addr_wq_lock); + if (!addrw) return; - } addrw->state = cmd; - list_add_tail(&addrw->list, &net->sctp.addr_waitq); + + spin_lock_bh(&net->sctp.addr_wq_lock); + list_add_tail_rcu(&addrw->list, &net->sctp.addr_waitq); pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n", __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);