ipv6: flowlabel: do not disable BH where not needed

struct ip6_flowlabel are rcu managed, and call_rcu() is used
to delay fl_free_rcu() after RCU grace period.

There is no point disabling BH for pure RCU lookups.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index 18481eb..b3ca4be 100644 (file)
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -58,18 +58,18 @@ DEFINE_STATIC_KEY_DEFERRED_FALSE(ipv6_flowlabel_exclusive, HZ);
 EXPORT_SYMBOL(ipv6_flowlabel_exclusive);
 
 #define for_each_fl_rcu(hash, fl)                              \
-       for (fl = rcu_dereference_bh(fl_ht[(hash)]);            \
+       for (fl = rcu_dereference(fl_ht[(hash)]);               \
             fl != NULL;                                        \
-            fl = rcu_dereference_bh(fl->next))
+            fl = rcu_dereference(fl->next))
 #define for_each_fl_continue_rcu(fl)                           \
-       for (fl = rcu_dereference_bh(fl->next);                 \
+       for (fl = rcu_dereference(fl->next);                    \
             fl != NULL;                                        \
-            fl = rcu_dereference_bh(fl->next))
+            fl = rcu_dereference(fl->next))
 
 #define for_each_sk_fl_rcu(np, sfl)                            \
-       for (sfl = rcu_dereference_bh(np->ipv6_fl_list);        \
+       for (sfl = rcu_dereference(np->ipv6_fl_list);   \
             sfl != NULL;                                       \
-            sfl = rcu_dereference_bh(sfl->next))
+            sfl = rcu_dereference(sfl->next))
 
 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
 {
@@ -86,11 +86,11 @@ static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
 {
        struct ip6_flowlabel *fl;
 
-       rcu_read_lock_bh();
+       rcu_read_lock();
        fl = __fl_lookup(net, label);
        if (fl && !atomic_inc_not_zero(&fl->users))
                fl = NULL;
-       rcu_read_unlock_bh();
+       rcu_read_unlock();
        return fl;
 }
 
@@ -217,6 +217,7 @@ static struct ip6_flowlabel *fl_intern(struct net *net,
 
        fl->label = label & IPV6_FLOWLABEL_MASK;
 
+       rcu_read_lock();
        spin_lock_bh(&ip6_fl_lock);
        if (label == 0) {
                for (;;) {
@@ -240,6 +241,7 @@ static struct ip6_flowlabel *fl_intern(struct net *net,
                if (lfl) {
                        atomic_inc(&lfl->users);
                        spin_unlock_bh(&ip6_fl_lock);
+                       rcu_read_unlock();
                        return lfl;
                }
        }
@@ -249,6 +251,7 @@ static struct ip6_flowlabel *fl_intern(struct net *net,
        rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);
        atomic_inc(&fl_size);
        spin_unlock_bh(&ip6_fl_lock);
+       rcu_read_unlock();
        return NULL;
 }
 
@@ -263,17 +266,17 @@ struct ip6_flowlabel *__fl6_sock_lookup(struct sock *sk, __be32 label)
 
        label &= IPV6_FLOWLABEL_MASK;
 
-       rcu_read_lock_bh();
+       rcu_read_lock();
        for_each_sk_fl_rcu(np, sfl) {
                struct ip6_flowlabel *fl = sfl->fl;
 
                if (fl->label == label && atomic_inc_not_zero(&fl->users)) {
                        fl->lastuse = jiffies;
-                       rcu_read_unlock_bh();
+                       rcu_read_unlock();
                        return fl;
                }
        }
-       rcu_read_unlock_bh();
+       rcu_read_unlock();
        return NULL;
 }
 EXPORT_SYMBOL_GPL(__fl6_sock_lookup);
@@ -475,10 +478,10 @@ static int mem_check(struct sock *sk)
        if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
                return 0;
 
-       rcu_read_lock_bh();
+       rcu_read_lock();
        for_each_sk_fl_rcu(np, sfl)
                count++;
-       rcu_read_unlock_bh();
+       rcu_read_unlock();
 
        if (room <= 0 ||
            ((count >= FL_MAX_PER_SOCK ||
@@ -515,7 +518,7 @@ int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
                return 0;
        }
 
-       rcu_read_lock_bh();
+       rcu_read_lock();
 
        for_each_sk_fl_rcu(np, sfl) {
                if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
@@ -527,11 +530,11 @@ int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
                        freq->flr_linger = sfl->fl->linger / HZ;
 
                        spin_unlock_bh(&ip6_fl_lock);
-                       rcu_read_unlock_bh();
+                       rcu_read_unlock();
                        return 0;
                }
        }
-       rcu_read_unlock_bh();
+       rcu_read_unlock();
 
        return -ENOENT;
 }
@@ -581,16 +584,16 @@ static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq)
        struct ipv6_fl_socklist *sfl;
        int err;
 
-       rcu_read_lock_bh();
+       rcu_read_lock();
        for_each_sk_fl_rcu(np, sfl) {
                if (sfl->fl->label == freq->flr_label) {
                        err = fl6_renew(sfl->fl, freq->flr_linger,
                                        freq->flr_expires);
-                       rcu_read_unlock_bh();
+                       rcu_read_unlock();
                        return err;
                }
        }
-       rcu_read_unlock_bh();
+       rcu_read_unlock();
 
        if (freq->flr_share == IPV6_FL_S_NONE &&
            ns_capable(net->user_ns, CAP_NET_ADMIN)) {
@@ -641,11 +644,11 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 
        if (freq->flr_label) {
                err = -EEXIST;
-               rcu_read_lock_bh();
+               rcu_read_lock();
                for_each_sk_fl_rcu(np, sfl) {
                        if (sfl->fl->label == freq->flr_label) {
                                if (freq->flr_flags & IPV6_FL_F_EXCL) {
-                                       rcu_read_unlock_bh();
+                                       rcu_read_unlock();
                                        goto done;
                                }
                                fl1 = sfl->fl;
@@ -654,7 +657,7 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
                                break;
                        }
                }
-               rcu_read_unlock_bh();
+               rcu_read_unlock();
 
                if (!fl1)
                        fl1 = fl_lookup(net, freq->flr_label);
@@ -809,7 +812,7 @@ static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 
        state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb);
 
-       rcu_read_lock_bh();
+       rcu_read_lock();
        return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 }
 
@@ -828,7 +831,7 @@ static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
        __releases(RCU)
 {
-       rcu_read_unlock_bh();
+       rcu_read_unlock();
 }
 
 static int ip6fl_seq_show(struct seq_file *seq, void *v)