Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Conflicts:
	drivers/net/usb/asix_common.c
	net/ipv4/inet_connection_sock.c
	net/switchdev/switchdev.c

In the inet_connection_sock.c case the request socket hashing scheme
is completely different in net-next.

The other two conflicts were overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 12 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 8f060d7f9a0e..0a49a8c7c564 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2785,6 +2785,7 @@ static int netlink_dump(struct sock *sk)
         struct sk_buff *skb = NULL;
         struct nlmsghdr *nlh;
         int len, err = -ENOBUFS;
+        int alloc_min_size;
         int alloc_size;
 
         mutex_lock(nlk->cb_mutex);
@@ -2793,9 +2794,6 @@ static int netlink_dump(struct sock *sk)
                 goto errout_skb;
         }
 
-        cb = &nlk->cb;
-        alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
-
         if (!netlink_rx_is_mmaped(sk) &&
             atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
                 goto errout_skb;
@@ -2805,23 +2803,35 @@ static int netlink_dump(struct sock *sk)
          * to reduce number of system calls on dump operations, if user
          * ever provided a big enough buffer.
          */
-        if (alloc_size < nlk->max_recvmsg_len) {
-                skb = netlink_alloc_skb(sk,
-                                        nlk->max_recvmsg_len,
-                                        nlk->portid,
+        cb = &nlk->cb;
+        alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
+
+        if (alloc_min_size < nlk->max_recvmsg_len) {
+                alloc_size = nlk->max_recvmsg_len;
+                skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
                                         GFP_KERNEL |
                                         __GFP_NOWARN |
                                         __GFP_NORETRY);
-                /* available room should be exact amount to avoid MSG_TRUNC */
-                if (skb)
-                        skb_reserve(skb, skb_tailroom(skb) -
-                                         nlk->max_recvmsg_len);
         }
-        if (!skb)
+        if (!skb) {
+                alloc_size = alloc_min_size;
                 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
                                         GFP_KERNEL);
+        }
         if (!skb)
                 goto errout_skb;
+
+        /* Trim skb to allocated size. User is expected to provide buffer as
+         * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
+         * netlink_recvmsg())). dump will pack as many smaller messages as
+         * could fit within the allocated skb. skb is typically allocated
+         * with larger space than required (could be as much as near 2x the
+         * requested size with align to next power of 2 approach). Allowing
+         * dump to use the excess space makes it difficult for a user to have a
+         * reasonable static buffer based on the expected largest dump of a
+         * single netdev. The outcome is MSG_TRUNC error.
+         */
+        skb_reserve(skb, skb_tailroom(skb) - alloc_size);
         netlink_skb_set_owner_r(skb, sk);
 
         len = cb->dump(skb, cb);