ipv4: ipmr: convert struct mfc_cache to struct list_head

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 64 insertions, 67 deletions

diff --git a/include/linux/mroute.h b/include/linux/mroute.h
index de7780a6dd32..7ff6c77d6008 100644
--- a/include/linux/mroute.h
+++ b/include/linux/mroute.h
@@ -191,7 +191,7 @@ struct vif_device {
 #define VIFF_STATIC 0x8000
 
 struct mfc_cache {
-        struct mfc_cache *next;                 /* Next entry on cache line     */
+        struct list_head list;
         __be32 mfc_mcastgrp;                    /* Group the entry belongs to   */
         __be32 mfc_origin;                      /* Source of packet             */
         vifi_t mfc_parent;                      /* Source interface             */
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index b15e518f952a..5d06429968d5 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -61,8 +61,8 @@ struct netns_ipv4 {
 #ifdef CONFIG_IP_MROUTE
         struct sock             *mroute_sk;
         struct timer_list       ipmr_expire_timer;
-        struct mfc_cache        *mfc_unres_queue;
-        struct mfc_cache        **mfc_cache_array;
+        struct list_head        mfc_unres_queue;
+        struct list_head        *mfc_cache_array;
         struct vif_device       *vif_table;
         int                     maxvif;
         atomic_t                cache_resolve_queue_len;
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index f8e25c8ba070..21b5edc2f343 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -367,35 +367,32 @@ static void ipmr_expire_process(unsigned long arg)
         struct net *net = (struct net *)arg;
         unsigned long now;
         unsigned long expires;
-        struct mfc_cache *c, **cp;
+        struct mfc_cache *c, *next;
 
         if (!spin_trylock(&mfc_unres_lock)) {
                 mod_timer(&net->ipv4.ipmr_expire_timer, jiffies+HZ/10);
                 return;
         }
 
-        if (net->ipv4.mfc_unres_queue == NULL)
+        if (list_empty(&net->ipv4.mfc_unres_queue))
                 goto out;
 
         now = jiffies;
         expires = 10*HZ;
-        cp = &net->ipv4.mfc_unres_queue;
 
-        while ((c=*cp) != NULL) {
+        list_for_each_entry_safe(c, next, &net->ipv4.mfc_unres_queue, list) {
                 if (time_after(c->mfc_un.unres.expires, now)) {
                         unsigned long interval = c->mfc_un.unres.expires - now;
                         if (interval < expires)
                                 expires = interval;
-                        cp = &c->next;
                         continue;
                 }
 
-                *cp = c->next;
-
+                list_del(&c->list);
                 ipmr_destroy_unres(net, c);
         }
 
-        if (net->ipv4.mfc_unres_queue != NULL)
+        if (!list_empty(&net->ipv4.mfc_unres_queue))
                 mod_timer(&net->ipv4.ipmr_expire_timer, jiffies + expires);
 
 out:
@@ -537,11 +534,11 @@ static struct mfc_cache *ipmr_cache_find(struct net *net,
         int line = MFC_HASH(mcastgrp, origin);
         struct mfc_cache *c;
 
-        for (c = net->ipv4.mfc_cache_array[line]; c; c = c->next) {
-                if (c->mfc_origin==origin && c->mfc_mcastgrp==mcastgrp)
-                        break;
+        list_for_each_entry(c, &net->ipv4.mfc_cache_array[line], list) {
+                if (c->mfc_origin == origin && c->mfc_mcastgrp == mcastgrp)
+                        return c;
         }
-        return c;
+        return NULL;
 }
 
 /*
@@ -699,18 +696,21 @@ static int ipmr_cache_report(struct net *net,
 static int
 ipmr_cache_unresolved(struct net *net, vifi_t vifi, struct sk_buff *skb)
 {
+        bool found = false;
         int err;
         struct mfc_cache *c;
         const struct iphdr *iph = ip_hdr(skb);
 
         spin_lock_bh(&mfc_unres_lock);
-        for (c=net->ipv4.mfc_unres_queue; c; c=c->next) {
+        list_for_each_entry(c, &net->ipv4.mfc_unres_queue, list) {
                 if (c->mfc_mcastgrp == iph->daddr &&
-                    c->mfc_origin == iph->saddr)
+                    c->mfc_origin == iph->saddr) {
+                        found = true;
                         break;
+                }
         }
 
-        if (c == NULL) {
+        if (!found) {
                 /*
                  *      Create a new entry if allowable
                  */
@@ -746,8 +746,7 @@ ipmr_cache_unresolved(struct net *net, vifi_t vifi, struct sk_buff *skb)
                 }
 
                 atomic_inc(&net->ipv4.cache_resolve_queue_len);
-                c->next = net->ipv4.mfc_unres_queue;
-                net->ipv4.mfc_unres_queue = c;
+                list_add(&c->list, &net->ipv4.mfc_unres_queue);
 
                 mod_timer(&net->ipv4.ipmr_expire_timer, c->mfc_un.unres.expires);
         }
@@ -774,16 +773,15 @@ ipmr_cache_unresolved(struct net *net, vifi_t vifi, struct sk_buff *skb)
 static int ipmr_mfc_delete(struct net *net, struct mfcctl *mfc)
 {
         int line;
-        struct mfc_cache *c, **cp;
+        struct mfc_cache *c, *next;
 
         line = MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr);
 
-        for (cp = &net->ipv4.mfc_cache_array[line];
-             (c = *cp) != NULL; cp = &c->next) {
+        list_for_each_entry_safe(c, next, &net->ipv4.mfc_cache_array[line], list) {
                 if (c->mfc_origin == mfc->mfcc_origin.s_addr &&
                     c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) {
                         write_lock_bh(&mrt_lock);
-                        *cp = c->next;
+                        list_del(&c->list);
                         write_unlock_bh(&mrt_lock);
 
                         ipmr_cache_free(c);
@@ -795,22 +793,24 @@ static int ipmr_mfc_delete(struct net *net, struct mfcctl *mfc)
 
 static int ipmr_mfc_add(struct net *net, struct mfcctl *mfc, int mrtsock)
 {
+        bool found = false;
         int line;
-        struct mfc_cache *uc, *c, **cp;
+        struct mfc_cache *uc, *c;
 
         if (mfc->mfcc_parent >= MAXVIFS)
                 return -ENFILE;
 
         line = MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr);
 
-        for (cp = &net->ipv4.mfc_cache_array[line];
-             (c = *cp) != NULL; cp = &c->next) {
+        list_for_each_entry(c, &net->ipv4.mfc_cache_array[line], list) {
                 if (c->mfc_origin == mfc->mfcc_origin.s_addr &&
-                    c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr)
+                    c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) {
+                        found = true;
                         break;
+                }
         }
 
-        if (c != NULL) {
+        if (found) {
                 write_lock_bh(&mrt_lock);
                 c->mfc_parent = mfc->mfcc_parent;
                 ipmr_update_thresholds(net, c, mfc->mfcc_ttls);
@@ -835,8 +835,7 @@ static int ipmr_mfc_add(struct net *net, struct mfcctl *mfc, int mrtsock)
                 c->mfc_flags |= MFC_STATIC;
 
         write_lock_bh(&mrt_lock);
-        c->next = net->ipv4.mfc_cache_array[line];
-        net->ipv4.mfc_cache_array[line] = c;
+        list_add(&c->list, &net->ipv4.mfc_cache_array[line]);
         write_unlock_bh(&mrt_lock);
 
         /*
@@ -844,16 +843,15 @@ static int ipmr_mfc_add(struct net *net, struct mfcctl *mfc, int mrtsock)
          *      need to send on the frames and tidy up.
          */
         spin_lock_bh(&mfc_unres_lock);
-        for (cp = &net->ipv4.mfc_unres_queue; (uc=*cp) != NULL;
-             cp = &uc->next) {
+        list_for_each_entry(uc, &net->ipv4.mfc_unres_queue, list) {
                 if (uc->mfc_origin == c->mfc_origin &&
                     uc->mfc_mcastgrp == c->mfc_mcastgrp) {
-                        *cp = uc->next;
+                        list_del(&uc->list);
                         atomic_dec(&net->ipv4.cache_resolve_queue_len);
                         break;
                 }
         }
-        if (net->ipv4.mfc_unres_queue == NULL)
+        if (list_empty(&net->ipv4.mfc_unres_queue))
                 del_timer(&net->ipv4.ipmr_expire_timer);
         spin_unlock_bh(&mfc_unres_lock);
 
@@ -872,6 +870,7 @@ static void mroute_clean_tables(struct net *net)
 {
         int i;
         LIST_HEAD(list);
+        struct mfc_cache *c, *next;
 
         /*
          *      Shut down all active vif entries
@@ -885,17 +884,12 @@ static void mroute_clean_tables(struct net *net)
         /*
          *      Wipe the cache
          */
-        for (i=0; i<MFC_LINES; i++) {
-                struct mfc_cache *c, **cp;
-
-                cp = &net->ipv4.mfc_cache_array[i];
-                while ((c = *cp) != NULL) {
-                        if (c->mfc_flags&MFC_STATIC) {
-                                cp = &c->next;
+        for (i = 0; i < MFC_LINES; i++) {
+                list_for_each_entry_safe(c, next, &net->ipv4.mfc_cache_array[i], list) {
+                        if (c->mfc_flags&MFC_STATIC)
                                 continue;
-                        }
                         write_lock_bh(&mrt_lock);
-                        *cp = c->next;
+                        list_del(&c->list);
                         write_unlock_bh(&mrt_lock);
 
                         ipmr_cache_free(c);
@@ -903,12 +897,9 @@ static void mroute_clean_tables(struct net *net)
         }
 
         if (atomic_read(&net->ipv4.cache_resolve_queue_len) != 0) {
-                struct mfc_cache *c, **cp;
-
                 spin_lock_bh(&mfc_unres_lock);
-                cp = &net->ipv4.mfc_unres_queue;
-                while ((c = *cp) != NULL) {
-                        *cp = c->next;
+                list_for_each_entry_safe(c, next, &net->ipv4.mfc_unres_queue, list) {
+                        list_del(&c->list);
                         ipmr_destroy_unres(net, c);
                 }
                 spin_unlock_bh(&mfc_unres_lock);
@@ -1789,7 +1780,7 @@ static const struct file_operations ipmr_vif_fops = {
 
 struct ipmr_mfc_iter {
         struct seq_net_private p;
-        struct mfc_cache **cache;
+        struct list_head *cache;
         int ct;
 };
 
@@ -1799,18 +1790,18 @@ static struct mfc_cache *ipmr_mfc_seq_idx(struct net *net,
 {
         struct mfc_cache *mfc;
 
-        it->cache = net->ipv4.mfc_cache_array;
         read_lock(&mrt_lock);
-        for (it->ct = 0; it->ct < MFC_LINES; it->ct++)
-                for (mfc = net->ipv4.mfc_cache_array[it->ct];
-                     mfc; mfc = mfc->next)
+        for (it->ct = 0; it->ct < MFC_LINES; it->ct++) {
+                it->cache = &net->ipv4.mfc_cache_array[it->ct];
+                list_for_each_entry(mfc, it->cache, list)
                         if (pos-- == 0)
                                 return mfc;
+        }
         read_unlock(&mrt_lock);
 
-        it->cache = &net->ipv4.mfc_unres_queue;
         spin_lock_bh(&mfc_unres_lock);
-        for (mfc = net->ipv4.mfc_unres_queue; mfc; mfc = mfc->next)
+        it->cache = &net->ipv4.mfc_unres_queue;
+        list_for_each_entry(mfc, it->cache, list)
                 if (pos-- == 0)
                         return mfc;
         spin_unlock_bh(&mfc_unres_lock);
@@ -1842,18 +1833,19 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
         if (v == SEQ_START_TOKEN)
                 return ipmr_mfc_seq_idx(net, seq->private, 0);
 
-        if (mfc->next)
-                return mfc->next;
+        if (mfc->list.next != it->cache)
+                return list_entry(mfc->list.next, struct mfc_cache, list);
 
         if (it->cache == &net->ipv4.mfc_unres_queue)
                 goto end_of_list;
 
-        BUG_ON(it->cache != net->ipv4.mfc_cache_array);
+        BUG_ON(it->cache != &net->ipv4.mfc_cache_array[it->ct]);
 
         while (++it->ct < MFC_LINES) {
-                mfc = net->ipv4.mfc_cache_array[it->ct];
-                if (mfc)
-                        return mfc;
+                it->cache = &net->ipv4.mfc_cache_array[it->ct];
+                if (list_empty(it->cache))
+                        continue;
+                return list_first_entry(it->cache, struct mfc_cache, list);
         }
 
         /* exhausted cache_array, show unresolved */
@@ -1862,9 +1854,8 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
         it->ct = 0;
 
         spin_lock_bh(&mfc_unres_lock);
-        mfc = net->ipv4.mfc_unres_queue;
-        if (mfc)
-                return mfc;
+        if (!list_empty(it->cache))
+                return list_first_entry(it->cache, struct mfc_cache, list);
 
  end_of_list:
         spin_unlock_bh(&mfc_unres_lock);
@@ -1880,7 +1871,7 @@ static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
 
         if (it->cache == &net->ipv4.mfc_unres_queue)
                 spin_unlock_bh(&mfc_unres_lock);
-        else if (it->cache == net->ipv4.mfc_cache_array)
+        else if (it->cache == &net->ipv4.mfc_cache_array[it->ct])
                 read_unlock(&mrt_lock);
 }
 
@@ -1960,6 +1951,7 @@ static const struct net_protocol pim_protocol = {
  */
 static int __net_init ipmr_net_init(struct net *net)
 {
+        unsigned int i;
         int err = 0;
 
         net->ipv4.vif_table = kcalloc(MAXVIFS, sizeof(struct vif_device),
@@ -1971,13 +1963,18 @@ static int __net_init ipmr_net_init(struct net *net)
 
         /* Forwarding cache */
         net->ipv4.mfc_cache_array = kcalloc(MFC_LINES,
-                                            sizeof(struct mfc_cache *),
+                                            sizeof(struct list_head),
                                             GFP_KERNEL);
         if (!net->ipv4.mfc_cache_array) {
                 err = -ENOMEM;
                 goto fail_mfc_cache;
         }
 
+        for (i = 0; i < MFC_LINES; i++)
+                INIT_LIST_HEAD(&net->ipv4.mfc_cache_array[i]);
+
+        INIT_LIST_HEAD(&net->ipv4.mfc_unres_queue);
+
         setup_timer(&net->ipv4.ipmr_expire_timer, ipmr_expire_process,
                     (unsigned long)net);