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Date: Thu, 13 Sep 2007 13:00:12 -0700
From: Sridhar Samudrala <sri@...ibm.com>
To: Vlad Yasevich <vladislav.yasevich@...com>
Cc: netdev@...r.kernel.org, lksctp@...com
Subject: Re: [v3 PATCH 2/2] SCTP: Convert bind_addr_list locking to RCU
On Thu, 2007-09-13 at 15:34 -0400, Vlad Yasevich wrote:
> Since the sctp_sockaddr_entry is now RCU enabled as part of
> the patch to synchronize sctp_localaddr_list, it makes sense to
> change all handling of these entries to RCU. This includes the
> sctp_bind_addrs structure and it's list of bound addresses.
>
> This list is currently protected by an external rw_lock and that
> looks like an overkill. There are only 2 writers to the list:
> bind()/bindx() calls, and BH processing of ASCONF-ACK chunks.
> These are already seriealized via the socket lock, so they will
> not step on each other. These are also relatively rare, so we
> should be good with RCU.
>
> The readers are varied and they are easily converted to RCU.
>
> Signed-off-by: Vlad Yasevich <vladislav.yasevich@...com>
> Acked-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Acked-by: Sridhar Samudrala <sri@...ibm.com>
Thanks
Sridhar
> ---
> include/net/sctp/structs.h | 7 +--
> net/sctp/associola.c | 14 +-----
> net/sctp/bind_addr.c | 68 ++++++++++++++++++++----------
> net/sctp/endpointola.c | 27 +++---------
> net/sctp/ipv6.c | 12 ++---
> net/sctp/protocol.c | 25 ++++-------
> net/sctp/sm_make_chunk.c | 18 +++-----
> net/sctp/socket.c | 98 ++++++++++++-------------------------------
> 8 files changed, 106 insertions(+), 163 deletions(-)
>
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index a89e361..c2fe2dc 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -1155,7 +1155,9 @@ int sctp_bind_addr_copy(struct sctp_bind_addr *dest,
> int flags);
> int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
> __u8 use_as_src, gfp_t gfp);
> -int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
> +int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
> + void (*rcu_call)(struct rcu_head *,
> + void (*func)(struct rcu_head *)));
> int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
> struct sctp_sock *);
> union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr *bp,
> @@ -1226,9 +1228,6 @@ struct sctp_ep_common {
> * bind_addr.address_list is our set of local IP addresses.
> */
> struct sctp_bind_addr bind_addr;
> -
> - /* Protection during address list comparisons. */
> - rwlock_t addr_lock;
> };
>
>
> diff --git a/net/sctp/associola.c b/net/sctp/associola.c
> index 2ad1caf..9bad8ba 100644
> --- a/net/sctp/associola.c
> +++ b/net/sctp/associola.c
> @@ -99,7 +99,6 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
>
> /* Initialize the bind addr area. */
> sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
> - rwlock_init(&asoc->base.addr_lock);
>
> asoc->state = SCTP_STATE_CLOSED;
>
> @@ -937,8 +936,6 @@ struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
> {
> struct sctp_transport *transport;
>
> - sctp_read_lock(&asoc->base.addr_lock);
> -
> if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
> (htons(asoc->peer.port) == paddr->v4.sin_port)) {
> transport = sctp_assoc_lookup_paddr(asoc, paddr);
> @@ -952,7 +949,6 @@ struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
> transport = NULL;
>
> out:
> - sctp_read_unlock(&asoc->base.addr_lock);
> return transport;
> }
>
> @@ -1376,19 +1372,13 @@ int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
> int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
> const union sctp_addr *laddr)
> {
> - int found;
> + int found = 0;
>
> - sctp_read_lock(&asoc->base.addr_lock);
> if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
> sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
> - sctp_sk(asoc->base.sk))) {
> + sctp_sk(asoc->base.sk)))
> found = 1;
> - goto out;
> - }
>
> - found = 0;
> -out:
> - sctp_read_unlock(&asoc->base.addr_lock);
> return found;
> }
>
> diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
> index 7fc369f..d35cbf5 100644
> --- a/net/sctp/bind_addr.c
> +++ b/net/sctp/bind_addr.c
> @@ -167,7 +167,11 @@ int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
>
> INIT_LIST_HEAD(&addr->list);
> INIT_RCU_HEAD(&addr->rcu);
> - list_add_tail(&addr->list, &bp->address_list);
> +
> + /* We always hold a socket lock when calling this function,
> + * and that acts as a writer synchronizing lock.
> + */
> + list_add_tail_rcu(&addr->list, &bp->address_list);
> SCTP_DBG_OBJCNT_INC(addr);
>
> return 0;
> @@ -176,23 +180,35 @@ int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
> /* Delete an address from the bind address list in the SCTP_bind_addr
> * structure.
> */
> -int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
> +int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr,
> + void (*rcu_call)(struct rcu_head *head,
> + void (*func)(struct rcu_head *head)))
> {
> - struct list_head *pos, *temp;
> - struct sctp_sockaddr_entry *addr;
> + struct sctp_sockaddr_entry *addr, *temp;
>
> - list_for_each_safe(pos, temp, &bp->address_list) {
> - addr = list_entry(pos, struct sctp_sockaddr_entry, list);
> + /* We hold the socket lock when calling this function,
> + * and that acts as a writer synchronizing lock.
> + */
> + list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
> if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
> /* Found the exact match. */
> - list_del(pos);
> - kfree(addr);
> - SCTP_DBG_OBJCNT_DEC(addr);
> -
> - return 0;
> + addr->valid = 0;
> + list_del_rcu(&addr->list);
> + break;
> }
> }
>
> + /* Call the rcu callback provided in the args. This function is
> + * called by both BH packet processing and user side socket option
> + * processing, but it works on different lists in those 2 contexts.
> + * Each context provides it's own callback, whether call_rcu_bh()
> + * or call_rcu(), to make sure that we wait for an appropriate time.
> + */
> + if (addr && !addr->valid) {
> + rcu_call(&addr->rcu, sctp_local_addr_free);
> + SCTP_DBG_OBJCNT_DEC(addr);
> + }
> +
> return -EINVAL;
> }
>
> @@ -302,15 +318,20 @@ int sctp_bind_addr_match(struct sctp_bind_addr *bp,
> struct sctp_sock *opt)
> {
> struct sctp_sockaddr_entry *laddr;
> - struct list_head *pos;
> -
> - list_for_each(pos, &bp->address_list) {
> - laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
> - if (opt->pf->cmp_addr(&laddr->a, addr, opt))
> - return 1;
> + int match = 0;
> +
> + rcu_read_lock();
> + list_for_each_entry_rcu(laddr, &bp->address_list, list) {
> + if (!laddr->valid)
> + continue;
> + if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
> + match = 1;
> + break;
> + }
> }
> + rcu_read_unlock();
>
> - return 0;
> + return match;
> }
>
> /* Find the first address in the bind address list that is not present in
> @@ -325,18 +346,19 @@ union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr *bp,
> union sctp_addr *addr;
> void *addr_buf;
> struct sctp_af *af;
> - struct list_head *pos;
> int i;
>
> - list_for_each(pos, &bp->address_list) {
> - laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
> -
> + /* This is only called sctp_send_asconf_del_ip() and we hold
> + * the socket lock in that code patch, so that address list
> + * can't change.
> + */
> + list_for_each_entry(laddr, &bp->address_list, list) {
> addr_buf = (union sctp_addr *)addrs;
> for (i = 0; i < addrcnt; i++) {
> addr = (union sctp_addr *)addr_buf;
> af = sctp_get_af_specific(addr->v4.sin_family);
> if (!af)
> - return NULL;
> + break;
>
> if (opt->pf->cmp_addr(&laddr->a, addr, opt))
> break;
> diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
> index 1404a9e..8f485a0 100644
> --- a/net/sctp/endpointola.c
> +++ b/net/sctp/endpointola.c
> @@ -92,7 +92,6 @@ static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
>
> /* Initialize the bind addr area */
> sctp_bind_addr_init(&ep->base.bind_addr, 0);
> - rwlock_init(&ep->base.addr_lock);
>
> /* Remember who we are attached to. */
> ep->base.sk = sk;
> @@ -225,21 +224,14 @@ void sctp_endpoint_put(struct sctp_endpoint *ep)
> struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
> const union sctp_addr *laddr)
> {
> - struct sctp_endpoint *retval;
> + struct sctp_endpoint *retval = NULL;
>
> - sctp_read_lock(&ep->base.addr_lock);
> if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
> if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
> - sctp_sk(ep->base.sk))) {
> + sctp_sk(ep->base.sk)))
> retval = ep;
> - goto out;
> - }
> }
>
> - retval = NULL;
> -
> -out:
> - sctp_read_unlock(&ep->base.addr_lock);
> return retval;
> }
>
> @@ -261,9 +253,7 @@ static struct sctp_association *__sctp_endpoint_lookup_assoc(
> list_for_each(pos, &ep->asocs) {
> asoc = list_entry(pos, struct sctp_association, asocs);
> if (rport == asoc->peer.port) {
> - sctp_read_lock(&asoc->base.addr_lock);
> *transport = sctp_assoc_lookup_paddr(asoc, paddr);
> - sctp_read_unlock(&asoc->base.addr_lock);
>
> if (*transport)
> return asoc;
> @@ -295,20 +285,17 @@ struct sctp_association *sctp_endpoint_lookup_assoc(
> int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
> const union sctp_addr *paddr)
> {
> - struct list_head *pos;
> struct sctp_sockaddr_entry *addr;
> struct sctp_bind_addr *bp;
>
> - sctp_read_lock(&ep->base.addr_lock);
> bp = &ep->base.bind_addr;
> - list_for_each(pos, &bp->address_list) {
> - addr = list_entry(pos, struct sctp_sockaddr_entry, list);
> - if (sctp_has_association(&addr->a, paddr)) {
> - sctp_read_unlock(&ep->base.addr_lock);
> + /* This function is called with the socket lock held,
> + * so the address_list can not change.
> + */
> + list_for_each_entry(addr, &bp->address_list, list) {
> + if (sctp_has_association(&addr->a, paddr))
> return 1;
> - }
> }
> - sctp_read_unlock(&ep->base.addr_lock);
>
> return 0;
> }
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index e12fa0a..670fd27 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -302,9 +302,7 @@ static void sctp_v6_get_saddr(struct sctp_association *asoc,
> union sctp_addr *saddr)
> {
> struct sctp_bind_addr *bp;
> - rwlock_t *addr_lock;
> struct sctp_sockaddr_entry *laddr;
> - struct list_head *pos;
> sctp_scope_t scope;
> union sctp_addr *baddr = NULL;
> __u8 matchlen = 0;
> @@ -324,14 +322,14 @@ static void sctp_v6_get_saddr(struct sctp_association *asoc,
> scope = sctp_scope(daddr);
>
> bp = &asoc->base.bind_addr;
> - addr_lock = &asoc->base.addr_lock;
>
> /* Go through the bind address list and find the best source address
> * that matches the scope of the destination address.
> */
> - sctp_read_lock(addr_lock);
> - list_for_each(pos, &bp->address_list) {
> - laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
> + rcu_read_lock();
> + list_for_each_entry_rcu(laddr, &bp->address_list, list) {
> + if (!laddr->valid)
> + continue;
> if ((laddr->use_as_src) &&
> (laddr->a.sa.sa_family == AF_INET6) &&
> (scope <= sctp_scope(&laddr->a))) {
> @@ -353,7 +351,7 @@ static void sctp_v6_get_saddr(struct sctp_association *asoc,
> __FUNCTION__, asoc, NIP6(daddr->v6.sin6_addr));
> }
>
> - sctp_read_unlock(addr_lock);
> + rcu_read_unlock();
> }
>
> /* Make a copy of all potential local addresses. */
> diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
> index 7ee120e..3d036cd 100644
> --- a/net/sctp/protocol.c
> +++ b/net/sctp/protocol.c
> @@ -224,7 +224,7 @@ int sctp_copy_local_addr_list(struct sctp_bind_addr *bp, sctp_scope_t scope,
> (copy_flags & SCTP_ADDR6_ALLOWED) &&
> (copy_flags & SCTP_ADDR6_PEERSUPP)))) {
> error = sctp_add_bind_addr(bp, &addr->a, 1,
> - GFP_ATOMIC);
> + GFP_ATOMIC);
> if (error)
> goto end_copy;
> }
> @@ -428,9 +428,7 @@ static struct dst_entry *sctp_v4_get_dst(struct sctp_association *asoc,
> struct rtable *rt;
> struct flowi fl;
> struct sctp_bind_addr *bp;
> - rwlock_t *addr_lock;
> struct sctp_sockaddr_entry *laddr;
> - struct list_head *pos;
> struct dst_entry *dst = NULL;
> union sctp_addr dst_saddr;
>
> @@ -459,23 +457,20 @@ static struct dst_entry *sctp_v4_get_dst(struct sctp_association *asoc,
> goto out;
>
> bp = &asoc->base.bind_addr;
> - addr_lock = &asoc->base.addr_lock;
>
> if (dst) {
> /* Walk through the bind address list and look for a bind
> * address that matches the source address of the returned dst.
> */
> - sctp_read_lock(addr_lock);
> - list_for_each(pos, &bp->address_list) {
> - laddr = list_entry(pos, struct sctp_sockaddr_entry,
> - list);
> - if (!laddr->use_as_src)
> + rcu_read_lock();
> + list_for_each_entry_rcu(laddr, &bp->address_list, list) {
> + if (!laddr->valid || !laddr->use_as_src)
> continue;
> sctp_v4_dst_saddr(&dst_saddr, dst, htons(bp->port));
> if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
> goto out_unlock;
> }
> - sctp_read_unlock(addr_lock);
> + rcu_read_unlock();
>
> /* None of the bound addresses match the source address of the
> * dst. So release it.
> @@ -487,10 +482,10 @@ static struct dst_entry *sctp_v4_get_dst(struct sctp_association *asoc,
> /* Walk through the bind address list and try to get a dst that
> * matches a bind address as the source address.
> */
> - sctp_read_lock(addr_lock);
> - list_for_each(pos, &bp->address_list) {
> - laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
> -
> + rcu_read_lock();
> + list_for_each_entry_rcu(laddr, &bp->address_list, list) {
> + if (!laddr->valid)
> + continue;
> if ((laddr->use_as_src) &&
> (AF_INET == laddr->a.sa.sa_family)) {
> fl.fl4_src = laddr->a.v4.sin_addr.s_addr;
> @@ -502,7 +497,7 @@ static struct dst_entry *sctp_v4_get_dst(struct sctp_association *asoc,
> }
>
> out_unlock:
> - sctp_read_unlock(addr_lock);
> + rcu_read_unlock();
> out:
> if (dst)
> SCTP_DEBUG_PRINTK("rt_dst:%u.%u.%u.%u, rt_src:%u.%u.%u.%u\n",
> diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
> index 79856c9..2e34220 100644
> --- a/net/sctp/sm_make_chunk.c
> +++ b/net/sctp/sm_make_chunk.c
> @@ -1531,7 +1531,7 @@ no_hmac:
> /* Also, add the destination address. */
> if (list_empty(&retval->base.bind_addr.address_list)) {
> sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest, 1,
> - GFP_ATOMIC);
> + GFP_ATOMIC);
> }
>
> retval->next_tsn = retval->c.initial_tsn;
> @@ -2613,22 +2613,16 @@ static int sctp_asconf_param_success(struct sctp_association *asoc,
>
> switch (asconf_param->param_hdr.type) {
> case SCTP_PARAM_ADD_IP:
> - sctp_local_bh_disable();
> - sctp_write_lock(&asoc->base.addr_lock);
> - list_for_each(pos, &bp->address_list) {
> - saddr = list_entry(pos, struct sctp_sockaddr_entry, list);
> + /* This is always done in BH context with a socket lock
> + * held, so the list can not change.
> + */
> + list_for_each_entry(saddr, &bp->address_list, list) {
> if (sctp_cmp_addr_exact(&saddr->a, &addr))
> saddr->use_as_src = 1;
> }
> - sctp_write_unlock(&asoc->base.addr_lock);
> - sctp_local_bh_enable();
> break;
> case SCTP_PARAM_DEL_IP:
> - sctp_local_bh_disable();
> - sctp_write_lock(&asoc->base.addr_lock);
> - retval = sctp_del_bind_addr(bp, &addr);
> - sctp_write_unlock(&asoc->base.addr_lock);
> - sctp_local_bh_enable();
> + retval = sctp_del_bind_addr(bp, &addr, call_rcu_bh);
> list_for_each(pos, &asoc->peer.transport_addr_list) {
> transport = list_entry(pos, struct sctp_transport,
> transports);
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index a3acf78..772fbfb 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -367,14 +367,10 @@ SCTP_STATIC int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
> if (!bp->port)
> bp->port = inet_sk(sk)->num;
>
> - /* Add the address to the bind address list. */
> - sctp_local_bh_disable();
> - sctp_write_lock(&ep->base.addr_lock);
> -
> - /* Use GFP_ATOMIC since BHs are disabled. */
> + /* Add the address to the bind address list.
> + * Use GFP_ATOMIC since BHs will be disabled.
> + */
> ret = sctp_add_bind_addr(bp, addr, 1, GFP_ATOMIC);
> - sctp_write_unlock(&ep->base.addr_lock);
> - sctp_local_bh_enable();
>
> /* Copy back into socket for getsockname() use. */
> if (!ret) {
> @@ -544,15 +540,12 @@ static int sctp_send_asconf_add_ip(struct sock *sk,
> if (i < addrcnt)
> continue;
>
> - /* Use the first address in bind addr list of association as
> - * Address Parameter of ASCONF CHUNK.
> + /* Use the first valid address in bind addr list of
> + * association as Address Parameter of ASCONF CHUNK.
> */
> - sctp_read_lock(&asoc->base.addr_lock);
> bp = &asoc->base.bind_addr;
> p = bp->address_list.next;
> laddr = list_entry(p, struct sctp_sockaddr_entry, list);
> - sctp_read_unlock(&asoc->base.addr_lock);
> -
> chunk = sctp_make_asconf_update_ip(asoc, &laddr->a, addrs,
> addrcnt, SCTP_PARAM_ADD_IP);
> if (!chunk) {
> @@ -567,8 +560,6 @@ static int sctp_send_asconf_add_ip(struct sock *sk,
> /* Add the new addresses to the bind address list with
> * use_as_src set to 0.
> */
> - sctp_local_bh_disable();
> - sctp_write_lock(&asoc->base.addr_lock);
> addr_buf = addrs;
> for (i = 0; i < addrcnt; i++) {
> addr = (union sctp_addr *)addr_buf;
> @@ -578,8 +569,6 @@ static int sctp_send_asconf_add_ip(struct sock *sk,
> GFP_ATOMIC);
> addr_buf += af->sockaddr_len;
> }
> - sctp_write_unlock(&asoc->base.addr_lock);
> - sctp_local_bh_enable();
> }
>
> out:
> @@ -651,13 +640,7 @@ static int sctp_bindx_rem(struct sock *sk, struct sockaddr *addrs, int addrcnt)
> * socket routing and failover schemes. Refer to comments in
> * sctp_do_bind(). -daisy
> */
> - sctp_local_bh_disable();
> - sctp_write_lock(&ep->base.addr_lock);
> -
> - retval = sctp_del_bind_addr(bp, sa_addr);
> -
> - sctp_write_unlock(&ep->base.addr_lock);
> - sctp_local_bh_enable();
> + retval = sctp_del_bind_addr(bp, sa_addr, call_rcu);
>
> addr_buf += af->sockaddr_len;
> err_bindx_rem:
> @@ -748,14 +731,16 @@ static int sctp_send_asconf_del_ip(struct sock *sk,
> * make sure that we do not delete all the addresses in the
> * association.
> */
> - sctp_read_lock(&asoc->base.addr_lock);
> bp = &asoc->base.bind_addr;
> laddr = sctp_find_unmatch_addr(bp, (union sctp_addr *)addrs,
> addrcnt, sp);
> - sctp_read_unlock(&asoc->base.addr_lock);
> if (!laddr)
> continue;
>
> + /* We do not need RCU protection throughout this loop
> + * because this is done under a socket lock from the
> + * setsockopt call.
> + */
> chunk = sctp_make_asconf_update_ip(asoc, laddr, addrs, addrcnt,
> SCTP_PARAM_DEL_IP);
> if (!chunk) {
> @@ -766,23 +751,16 @@ static int sctp_send_asconf_del_ip(struct sock *sk,
> /* Reset use_as_src flag for the addresses in the bind address
> * list that are to be deleted.
> */
> - sctp_local_bh_disable();
> - sctp_write_lock(&asoc->base.addr_lock);
> addr_buf = addrs;
> for (i = 0; i < addrcnt; i++) {
> laddr = (union sctp_addr *)addr_buf;
> af = sctp_get_af_specific(laddr->v4.sin_family);
> - list_for_each(pos1, &bp->address_list) {
> - saddr = list_entry(pos1,
> - struct sctp_sockaddr_entry,
> - list);
> + list_for_each_entry(saddr, &bp->address_list, list) {
> if (sctp_cmp_addr_exact(&saddr->a, laddr))
> saddr->use_as_src = 0;
> }
> addr_buf += af->sockaddr_len;
> }
> - sctp_write_unlock(&asoc->base.addr_lock);
> - sctp_local_bh_enable();
>
> /* Update the route and saddr entries for all the transports
> * as some of the addresses in the bind address list are
> @@ -4057,11 +4035,9 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
> int __user *optlen)
> {
> sctp_assoc_t id;
> - struct list_head *pos;
> struct sctp_bind_addr *bp;
> struct sctp_association *asoc;
> struct sctp_sockaddr_entry *addr;
> - rwlock_t *addr_lock;
> int cnt = 0;
>
> if (len < sizeof(sctp_assoc_t))
> @@ -4078,17 +4054,13 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
> */
> if (0 == id) {
> bp = &sctp_sk(sk)->ep->base.bind_addr;
> - addr_lock = &sctp_sk(sk)->ep->base.addr_lock;
> } else {
> asoc = sctp_id2assoc(sk, id);
> if (!asoc)
> return -EINVAL;
> bp = &asoc->base.bind_addr;
> - addr_lock = &asoc->base.addr_lock;
> }
>
> - sctp_read_lock(addr_lock);
> -
> /* If the endpoint is bound to 0.0.0.0 or ::0, count the valid
> * addresses from the global local address list.
> */
> @@ -4115,12 +4087,14 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
> goto done;
> }
>
> - list_for_each(pos, &bp->address_list) {
> + /* Protection on the bound address list is not needed,
> + * since in the socket option context we hold the socket lock,
> + * so there is no way that the bound address list can change.
> + */
> + list_for_each_entry(addr, &bp->address_list, list) {
> cnt ++;
> }
> -
> done:
> - sctp_read_unlock(addr_lock);
> return cnt;
> }
>
> @@ -4204,7 +4178,6 @@ static int sctp_getsockopt_local_addrs_old(struct sock *sk, int len,
> {
> struct sctp_bind_addr *bp;
> struct sctp_association *asoc;
> - struct list_head *pos;
> int cnt = 0;
> struct sctp_getaddrs_old getaddrs;
> struct sctp_sockaddr_entry *addr;
> @@ -4212,7 +4185,6 @@ static int sctp_getsockopt_local_addrs_old(struct sock *sk, int len,
> union sctp_addr temp;
> struct sctp_sock *sp = sctp_sk(sk);
> int addrlen;
> - rwlock_t *addr_lock;
> int err = 0;
> void *addrs;
> void *buf;
> @@ -4234,13 +4206,11 @@ static int sctp_getsockopt_local_addrs_old(struct sock *sk, int len,
> */
> if (0 == getaddrs.assoc_id) {
> bp = &sctp_sk(sk)->ep->base.bind_addr;
> - addr_lock = &sctp_sk(sk)->ep->base.addr_lock;
> } else {
> asoc = sctp_id2assoc(sk, getaddrs.assoc_id);
> if (!asoc)
> return -EINVAL;
> bp = &asoc->base.bind_addr;
> - addr_lock = &asoc->base.addr_lock;
> }
>
> to = getaddrs.addrs;
> @@ -4254,8 +4224,6 @@ static int sctp_getsockopt_local_addrs_old(struct sock *sk, int len,
> if (!addrs)
> return -ENOMEM;
>
> - sctp_read_lock(addr_lock);
> -
> /* If the endpoint is bound to 0.0.0.0 or ::0, get the valid
> * addresses from the global local address list.
> */
> @@ -4271,8 +4239,11 @@ static int sctp_getsockopt_local_addrs_old(struct sock *sk, int len,
> }
>
> buf = addrs;
> - list_for_each(pos, &bp->address_list) {
> - addr = list_entry(pos, struct sctp_sockaddr_entry, list);
> + /* Protection on the bound address list is not needed since
> + * in the socket option context we hold a socket lock and
> + * thus the bound address list can't change.
> + */
> + list_for_each_entry(addr, &bp->address_list, list) {
> memcpy(&temp, &addr->a, sizeof(temp));
> sctp_get_pf_specific(sk->sk_family)->addr_v4map(sp, &temp);
> addrlen = sctp_get_af_specific(temp.sa.sa_family)->sockaddr_len;
> @@ -4284,8 +4255,6 @@ static int sctp_getsockopt_local_addrs_old(struct sock *sk, int len,
> }
>
> copy_getaddrs:
> - sctp_read_unlock(addr_lock);
> -
> /* copy the entire address list into the user provided space */
> if (copy_to_user(to, addrs, bytes_copied)) {
> err = -EFAULT;
> @@ -4307,7 +4276,6 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len,
> {
> struct sctp_bind_addr *bp;
> struct sctp_association *asoc;
> - struct list_head *pos;
> int cnt = 0;
> struct sctp_getaddrs getaddrs;
> struct sctp_sockaddr_entry *addr;
> @@ -4315,7 +4283,6 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len,
> union sctp_addr temp;
> struct sctp_sock *sp = sctp_sk(sk);
> int addrlen;
> - rwlock_t *addr_lock;
> int err = 0;
> size_t space_left;
> int bytes_copied = 0;
> @@ -4336,13 +4303,11 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len,
> */
> if (0 == getaddrs.assoc_id) {
> bp = &sctp_sk(sk)->ep->base.bind_addr;
> - addr_lock = &sctp_sk(sk)->ep->base.addr_lock;
> } else {
> asoc = sctp_id2assoc(sk, getaddrs.assoc_id);
> if (!asoc)
> return -EINVAL;
> bp = &asoc->base.bind_addr;
> - addr_lock = &asoc->base.addr_lock;
> }
>
> to = optval + offsetof(struct sctp_getaddrs,addrs);
> @@ -4352,8 +4317,6 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len,
> if (!addrs)
> return -ENOMEM;
>
> - sctp_read_lock(addr_lock);
> -
> /* If the endpoint is bound to 0.0.0.0 or ::0, get the valid
> * addresses from the global local address list.
> */
> @@ -4365,21 +4328,24 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len,
> space_left, &bytes_copied);
> if (cnt < 0) {
> err = cnt;
> - goto error_lock;
> + goto out;
> }
> goto copy_getaddrs;
> }
> }
>
> buf = addrs;
> - list_for_each(pos, &bp->address_list) {
> - addr = list_entry(pos, struct sctp_sockaddr_entry, list);
> + /* Protection on the bound address list is not needed since
> + * in the socket option context we hold a socket lock and
> + * thus the bound address list can't change.
> + */
> + list_for_each_entry(addr, &bp->address_list, list) {
> memcpy(&temp, &addr->a, sizeof(temp));
> sctp_get_pf_specific(sk->sk_family)->addr_v4map(sp, &temp);
> addrlen = sctp_get_af_specific(temp.sa.sa_family)->sockaddr_len;
> if (space_left < addrlen) {
> err = -ENOMEM; /*fixme: right error?*/
> - goto error_lock;
> + goto out;
> }
> memcpy(buf, &temp, addrlen);
> buf += addrlen;
> @@ -4389,8 +4355,6 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len,
> }
>
> copy_getaddrs:
> - sctp_read_unlock(addr_lock);
> -
> if (copy_to_user(to, addrs, bytes_copied)) {
> err = -EFAULT;
> goto out;
> @@ -4401,12 +4365,6 @@ copy_getaddrs:
> }
> if (put_user(bytes_copied, optlen))
> err = -EFAULT;
> -
> - goto out;
> -
> -error_lock:
> - sctp_read_unlock(addr_lock);
> -
> out:
> kfree(addrs);
> return err;
-
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