Merge tag 'net-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Current release - regressions:

   - dsa: bcm_sf2: fix array overrun in bcm_sf2_num_active_ports()

  Previous releases - regressions:

   - introduce a shutdown method to mdio device drivers, and make DSA
     switch drivers compatible with masters disappearing on shutdown;
     preventing infinite reference wait

   - fix issues in mdiobus users related to ->shutdown vs ->remove

   - virtio-net: fix pages leaking when building skb in big mode

   - xen-netback: correct success/error reporting for the
     SKB-with-fraglist

   - dsa: tear down devlink port regions when tearing down the devlink
     port on error

   - nexthop: fix division by zero while replacing a resilient group

   - hns3: check queue, vf, vlan ids range before using

  Previous releases - always broken:

   - napi: fix race against netpoll causing NAPI getting stuck

   - mlx4_en: ensure link operstate is updated even if link comes up
     before netdev registration

   - bnxt_en: fix TX timeout when TX ring size is set to the smallest

   - enetc: fix illegal access when reading affinity_hint; prevent oops
     on sysfs access

   - mtk_eth_soc: avoid creating duplicate offload entries

  Misc:

   - core: correct the sock::sk_lock.owned lockdep annotations"

* tag 'net-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (51 commits)
  atlantic: Fix issue in the pm resume flow.
  net/mlx4_en: Don't allow aRFS for encapsulated packets
  net: mscc: ocelot: fix forwarding from BLOCKING ports remaining enabled
  net: ethernet: mtk_eth_soc: avoid creating duplicate offload entries
  nfc: st-nci: Add SPI ID matching DT compatible
  MAINTAINERS: remove Guvenc Gulce as net/smc maintainer
  nexthop: Fix memory leaks in nexthop notification chain listeners
  mptcp: ensure tx skbs always have the MPTCP ext
  qed: rdma - don't wait for resources under hw error recovery flow
  s390/qeth: fix deadlock during failing recovery
  s390/qeth: Fix deadlock in remove_discipline
  s390/qeth: fix NULL deref in qeth_clear_working_pool_list()
  net: dsa: realtek: register the MDIO bus under devres
  net: dsa: don't allocate the slave_mii_bus using devres
  Doc: networking: Fox a typo in ice.rst
  net: dsa: fix dsa_tree_setup error path
  net/smc: fix 'workqueue leaked lock' in smc_conn_abort_work
  net/smc: add missing error check in smc_clc_prfx_set()
  net: hns3: fix a return value error in hclge_get_reset_status()
  net: hns3: check vlan id before using it
  ...

1 files changed, 23 insertions, 14 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index 62627e868e03..512e629f9780 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3179,17 +3179,15 @@ EXPORT_SYMBOL(sock_init_data);
 
 void lock_sock_nested(struct sock *sk, int subclass)
 {
+	/* The sk_lock has mutex_lock() semantics here. */
+	mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);
+
 	might_sleep();
 	spin_lock_bh(&sk->sk_lock.slock);
 	if (sk->sk_lock.owned)
 		__lock_sock(sk);
 	sk->sk_lock.owned = 1;
-	spin_unlock(&sk->sk_lock.slock);
-	/*
-	 * The sk_lock has mutex_lock() semantics here:
-	 */
-	mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);
-	local_bh_enable();
+	spin_unlock_bh(&sk->sk_lock.slock);
 }
 EXPORT_SYMBOL(lock_sock_nested);
 
@@ -3227,24 +3225,35 @@ EXPORT_SYMBOL(release_sock);
  */
 bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock)
 {
+	/* The sk_lock has mutex_lock() semantics here. */
+	mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
+
 	might_sleep();
 	spin_lock_bh(&sk->sk_lock.slock);
 
-	if (!sk->sk_lock.owned)
+	if (!sk->sk_lock.owned) {
 		/*
-		 * Note : We must disable BH
+		 * Fast path return with bottom halves disabled and
+		 * sock::sk_lock.slock held.
+		 *
+		 * The 'mutex' is not contended and holding
+		 * sock::sk_lock.slock prevents all other lockers to
+		 * proceed so the corresponding unlock_sock_fast() can
+		 * avoid the slow path of release_sock() completely and
+		 * just release slock.
+		 *
+		 * From a semantical POV this is equivalent to 'acquiring'
+		 * the 'mutex', hence the corresponding lockdep
+		 * mutex_release() has to happen in the fast path of
+		 * unlock_sock_fast().
 		 */
 		return false;
+	}
 
 	__lock_sock(sk);
 	sk->sk_lock.owned = 1;
-	spin_unlock(&sk->sk_lock.slock);
-	/*
-	 * The sk_lock has mutex_lock() semantics here:
-	 */
-	mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
 	__acquire(&sk->sk_lock.slock);
-	local_bh_enable();
+	spin_unlock_bh(&sk->sk_lock.slock);
 	return true;
 }
 EXPORT_SYMBOL(lock_sock_fast);