[PATCH net-next v2 3/7] mld: add a new delayed_work, mc_delrec_work

[Taehee Yoo]

The goal of mc_delrec_work delayed work is to call mld_clear_delrec().
The mld_clear_delrec() is called under both data path and control path.
So, the context of mld_clear_delrec() can be atomic.
But this function accesses struct ifmcaddr6 and struct ip6_sf_list.
These structures are going to be protected by RTNL.
So, this function should be called in a sleepable context.

Suggested-by: Cong Wang <xiyou.wangc...@gmail.com>
Signed-off-by: Taehee Yoo <ap420...@gmail.com>
---
v1 -> v2:
 - Separated from previous big one patch.

 include/net/if_inet6.h |  1 +
 net/ipv6/mcast.c       | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index bec372283ac0..5946b5d76f7b 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -182,6 +182,7 @@ struct inet6_dev {
        struct delayed_work     mc_gq_work;     /* general query work */
        struct delayed_work     mc_ifc_work;    /* interface change work */
        struct delayed_work     mc_dad_work;    /* dad complete mc work */
+       struct delayed_work     mc_delrec_work; /* delete records work */
 
        struct ifacaddr6        *ac_list;
        rwlock_t                lock;
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 1f7fd3fbb4b6..ca8ca6faca4e 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1067,6 +1067,22 @@ static void mld_dad_stop_work(struct inet6_dev *idev)
                __in6_dev_put(idev);
 }
 
+static void mld_clear_delrec_start_work(struct inet6_dev *idev)
+{
+       write_lock_bh(&idev->lock);
+       if (!mod_delayed_work(mld_wq, &idev->mc_delrec_work, 0))
+               in6_dev_hold(idev);
+       write_unlock_bh(&idev->lock);
+}
+
+static void mld_clear_delrec_stop_work(struct inet6_dev *idev)
+{
+       write_lock_bh(&idev->lock);
+       if (cancel_delayed_work(&idev->mc_delrec_work))
+               __in6_dev_put(idev);
+       write_unlock_bh(&idev->lock);
+}
+
 /*
  *     IGMP handling (alias multicast ICMPv6 messages)
  */
@@ -1304,7 +1320,7 @@ static int mld_process_v1(struct inet6_dev *idev, struct 
mld_msg *mld,
        /* cancel the interface change work */
        mld_ifc_stop_work(idev);
        /* clear deleted report items */
-       mld_clear_delrec(idev);
+       mld_clear_delrec_start_work(idev);
 
        return 0;
 }
@@ -2120,6 +2136,18 @@ static void mld_dad_work(struct work_struct *work)
        in6_dev_put(idev);
 }
 
+static void mld_clear_delrec_work(struct work_struct *work)
+{
+       struct inet6_dev *idev = container_of(to_delayed_work(work),
+                       struct inet6_dev,
+                       mc_delrec_work);
+
+       rtnl_lock();
+       mld_clear_delrec(idev);
+       rtnl_unlock();
+       in6_dev_put(idev);
+}
+
 static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
        const struct in6_addr *psfsrc)
 {
@@ -2553,6 +2581,7 @@ void ipv6_mc_down(struct inet6_dev *idev)
        mld_gq_stop_work(idev);
        mld_dad_stop_work(idev);
        read_unlock_bh(&idev->lock);
+       mld_clear_delrec_stop_work(idev);
 }
 
 static void ipv6_mc_reset(struct inet6_dev *idev)
@@ -2593,6 +2622,7 @@ void ipv6_mc_init_dev(struct inet6_dev *idev)
        idev->mc_ifc_count = 0;
        INIT_DELAYED_WORK(&idev->mc_ifc_work, mld_ifc_work);
        INIT_DELAYED_WORK(&idev->mc_dad_work, mld_dad_work);
+       INIT_DELAYED_WORK(&idev->mc_delrec_work, mld_clear_delrec_work);
        ipv6_mc_reset(idev);
        write_unlock_bh(&idev->lock);
 }
-- 
2.17.1