mctp: Return new key from mctp_alloc_local_tag

In a future change, we will want the key available for future use after
allocating a new tag. This change returns the key from
mctp_alloc_local_tag, rather than just key->tag.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mctp/route.c b/net/mctp/route.c
index c23ab35..82cc10a 100644 (file)
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -532,14 +532,14 @@ static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
 /* Allocate a locally-owned tag value for (saddr, daddr), and reserve
  * it for the socket msk
  */
-static int mctp_alloc_local_tag(struct mctp_sock *msk,
-                               mctp_eid_t saddr, mctp_eid_t daddr, u8 *tagp)
+static struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
+                                               mctp_eid_t saddr,
+                                               mctp_eid_t daddr, u8 *tagp)
 {
        struct net *net = sock_net(&msk->sk);
        struct netns_mctp *mns = &net->mctp;
        struct mctp_sk_key *key, *tmp;
        unsigned long flags;
-       int rc = -EAGAIN;
        u8 tagbits;
 
        /* for NULL destination EIDs, we may get a response from any peer */
@@ -549,7 +549,7 @@ static int mctp_alloc_local_tag(struct mctp_sock *msk,
        /* be optimistic, alloc now */
        key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL);
        if (!key)
-               return -ENOMEM;
+               return ERR_PTR(-ENOMEM);
 
        /* 8 possible tag values */
        tagbits = 0xff;
@@ -591,18 +591,16 @@ static int mctp_alloc_local_tag(struct mctp_sock *msk,
                trace_mctp_key_acquire(key);
 
                *tagp = key->tag;
-               /* done with the key in this scope */
-               mctp_key_unref(key);
-               key = NULL;
-               rc = 0;
        }
 
        spin_unlock_irqrestore(&mns->keys_lock, flags);
 
-       if (!tagbits)
+       if (!tagbits) {
                kfree(key);
+               return ERR_PTR(-EBUSY);
+       }
 
-       return rc;
+       return key;
 }
 
 /* routing lookups */
@@ -740,6 +738,7 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
        struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
        struct mctp_skb_cb *cb = mctp_cb(skb);
        struct mctp_route tmp_rt;
+       struct mctp_sk_key *key;
        struct net_device *dev;
        struct mctp_hdr *hdr;
        unsigned long flags;
@@ -799,11 +798,16 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
                goto out_release;
 
        if (req_tag & MCTP_HDR_FLAG_TO) {
-               rc = mctp_alloc_local_tag(msk, saddr, daddr, &tag);
-               if (rc)
+               key = mctp_alloc_local_tag(msk, saddr, daddr, &tag);
+               if (IS_ERR(key)) {
+                       rc = PTR_ERR(key);
                        goto out_release;
+               }
+               /* done with the key in this scope */
+               mctp_key_unref(key);
                tag |= MCTP_HDR_FLAG_TO;
        } else {
+               key = NULL;
                tag = req_tag;
        }