netns: ipmr: declare counter cache_resolve_queue_len per-namespace

Preliminary work to make IPv4 multicast routing netns-aware.

Declare variable cache_resolve_queue_len per-namespace: move it into
struct netns_ipv4.

This variable counts the number of unresolved cache entries queued in the
list mfc_unres_queue. This list is kept global to all netns as the number
of entries per namespace is limited to 10 (hardcoded in routine
ipmr_cache_unresolved).
Entries belonging to different namespaces in mfc_unres_queue will be
identified by matching the mfc_net member introduced previously in
struct mfc_cache.

Keeping this list global to all netns, also allows us to keep a single
timer (ipmr_expire_timer) to handle their expiration.
In some places cache_resolve_queue_len value was tested for arming
or deleting the timer. These tests were equivalent to testing
mfc_unres_queue value instead and are replaced in this patch.

At the moment, cache_resolve_queue_len is only referenced in init_net.

Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 18 deletions

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 35b868dd3bfd..feafd14eb7b9 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -83,7 +83,6 @@ static int mroute_do_assert;				/* Set in PIM assert	*/
 static int mroute_do_pim;
 
 static struct mfc_cache *mfc_unres_queue;               /* Queue of unresolved entries */
-static atomic_t cache_resolve_queue_len;                /* Size of unresolved   */
 
 /* Special spinlock for queue of unresolved entries */
 static DEFINE_SPINLOCK(mfc_unres_lock);
@@ -340,7 +339,7 @@ static void ipmr_destroy_unres(struct mfc_cache *c)
         struct sk_buff *skb;
         struct nlmsgerr *e;
 
-        atomic_dec(&cache_resolve_queue_len);
+        atomic_dec(&init_net.ipv4.cache_resolve_queue_len);
 
         while ((skb = skb_dequeue(&c->mfc_un.unres.unresolved))) {
                 if (ip_hdr(skb)->version == 0) {
@@ -374,7 +373,7 @@ static void ipmr_expire_process(unsigned long dummy)
                 return;
         }
 
-        if (atomic_read(&cache_resolve_queue_len) == 0)
+        if (mfc_unres_queue == NULL)
                 goto out;
 
         now = jiffies;
@@ -395,7 +394,7 @@ static void ipmr_expire_process(unsigned long dummy)
                 ipmr_destroy_unres(c);
         }
 
-        if (atomic_read(&cache_resolve_queue_len))
+        if (mfc_unres_queue != NULL)
                 mod_timer(&ipmr_expire_timer, jiffies + expires);
 
 out:
@@ -690,7 +689,8 @@ ipmr_cache_unresolved(vifi_t vifi, struct sk_buff *skb)
 
         spin_lock_bh(&mfc_unres_lock);
         for (c=mfc_unres_queue; c; c=c->next) {
-                if (c->mfc_mcastgrp == iph->daddr &&
+                if (net_eq(mfc_net(c), &init_net) &&
+                    c->mfc_mcastgrp == iph->daddr &&
                     c->mfc_origin == iph->saddr)
                         break;
         }
@@ -700,7 +700,7 @@ ipmr_cache_unresolved(vifi_t vifi, struct sk_buff *skb)
                  *      Create a new entry if allowable
                  */
 
-                if (atomic_read(&cache_resolve_queue_len) >= 10 ||
+                if (atomic_read(&init_net.ipv4.cache_resolve_queue_len) >= 10 ||
                     (c = ipmr_cache_alloc_unres(&init_net)) == NULL) {
                         spin_unlock_bh(&mfc_unres_lock);
 
@@ -729,7 +729,7 @@ ipmr_cache_unresolved(vifi_t vifi, struct sk_buff *skb)
                         return err;
                 }
 
-                atomic_inc(&cache_resolve_queue_len);
+                atomic_inc(&init_net.ipv4.cache_resolve_queue_len);
                 c->next = mfc_unres_queue;
                 mfc_unres_queue = c;
 
@@ -827,14 +827,16 @@ static int ipmr_mfc_add(struct mfcctl *mfc, int mrtsock)
         spin_lock_bh(&mfc_unres_lock);
         for (cp = &mfc_unres_queue; (uc=*cp) != NULL;
              cp = &uc->next) {
-                if (uc->mfc_origin == c->mfc_origin &&
+                if (net_eq(mfc_net(uc), &init_net) &&
+                    uc->mfc_origin == c->mfc_origin &&
                     uc->mfc_mcastgrp == c->mfc_mcastgrp) {
                         *cp = uc->next;
-                        if (atomic_dec_and_test(&cache_resolve_queue_len))
-                                del_timer(&ipmr_expire_timer);
+                        atomic_dec(&init_net.ipv4.cache_resolve_queue_len);
                         break;
                 }
         }
+        if (mfc_unres_queue == NULL)
+                del_timer(&ipmr_expire_timer);
         spin_unlock_bh(&mfc_unres_lock);
 
         if (uc) {
@@ -880,18 +882,19 @@ static void mroute_clean_tables(struct sock *sk)
                 }
         }
 
-        if (atomic_read(&cache_resolve_queue_len) != 0) {
-                struct mfc_cache *c;
+        if (atomic_read(&init_net.ipv4.cache_resolve_queue_len) != 0) {
+                struct mfc_cache *c, **cp;
 
                 spin_lock_bh(&mfc_unres_lock);
-                while (mfc_unres_queue != NULL) {
-                        c = mfc_unres_queue;
-                        mfc_unres_queue = c->next;
-                        spin_unlock_bh(&mfc_unres_lock);
+                cp = &mfc_unres_queue;
+                while ((c = *cp) != NULL) {
+                        if (!net_eq(mfc_net(c), &init_net)) {
+                                cp = &c->next;
+                                continue;
+                        }
+                        *cp = c->next;
 
                         ipmr_destroy_unres(c);
-
-                        spin_lock_bh(&mfc_unres_lock);
                 }
                 spin_unlock_bh(&mfc_unres_lock);
         }