Merge branches 'rcu/staging-core', 'rcu/staging-docs' and 'rcu/stagin…

…g-kfree', remote-tracking branches 'paul/srcu-cf.2023.04.04a', 'fbq/rcu/lockdep.2023.03.27a' and 'fbq/rcu/rcutorture.2023.03.20a' into rcu/staging

Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst

@@ -277,7 +277,7 @@ the following access functions:
 
 Again, only one request in a given batch need actually carry out a
 grace-period operation, which means there must be an efficient way to
-identify which of many concurrent reqeusts will initiate the grace
+identify which of many concurrent requests will initiate the grace
 period, and that there be an efficient way for the remaining requests to
 wait for that grace period to complete. However, that is the topic of
 the next section.
@@ -405,7 +405,7 @@ Use of Workqueues
 In earlier implementations, the task requesting the expedited grace
 period also drove it to completion. This straightforward approach had
 the disadvantage of needing to account for POSIX signals sent to user
-tasks, so more recent implemementations use the Linux kernel's
+tasks, so more recent implementations use the Linux kernel's
 workqueues (see Documentation/core-api/workqueue.rst).
 
 The requesting task still does counter snapshotting and funnel-lock
@@ -465,7 +465,7 @@ corresponding disadvantage that workqueues cannot be used until they are
 initialized, which does not happen until some time after the scheduler
 spawns the first task. Given that there are parts of the kernel that
 really do want to execute grace periods during this mid-boot “dead
-zone”, expedited grace periods must do something else during thie time.
+zone”, expedited grace periods must do something else during this time.
 
 What they do is to fall back to the old practice of requiring that the
 requesting task drive the expedited grace period, as was the case before

Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst

@@ -168,7 +168,7 @@ an ``atomic_add_return()`` of zero) to detect idle CPUs.
 +-----------------------------------------------------------------------+
 
 The approach must be extended to handle one final case, that of waking a
-task blocked in ``synchronize_rcu()``. This task might be affinitied to
+task blocked in ``synchronize_rcu()``. This task might be affined to
 a CPU that is not yet aware that the grace period has ended, and thus
 might not yet be subject to the grace period's memory ordering.
 Therefore, there is an ``smp_mb()`` after the return from

Documentation/RCU/RTFP.txt

@@ -201,7 +201,7 @@ work looked at debugging uses of RCU [Seyster:2011:RFA:2075416.2075425].
 In 2012, Josh Triplett received his Ph.D. with his dissertation
 covering RCU-protected resizable hash tables and the relationship
 between memory barriers and read-side traversal order:  If the updater
-is making changes in the opposite direction from the read-side traveral
+is making changes in the opposite direction from the read-side traversal
 order, the updater need only execute a memory-barrier instruction,
 but if in the same direction, the updater needs to wait for a grace
 period between the individual updates [JoshTriplettPhD].  Also in 2012,
@@ -1245,7 +1245,7 @@ Oregon Health and Sciences University"
 [Viewed September 5, 2005]"
 ,annotation={
 	First posting showing how RCU can be safely adapted for
-	preemptable RCU read side critical sections.
+	preemptible RCU read side critical sections.
 }
 }
 
@@ -1888,7 +1888,7 @@ Revised:
 \url{https://lore.kernel.org/r/20070910183004.GA3299@linux.vnet.ibm.com}
 [Viewed October 25, 2007]"
 ,annotation={
-	Final patch for preemptable RCU to -rt.  (Later patches were
+	Final patch for preemptible RCU to -rt.  (Later patches were
 	to mainline, eventually incorporated.)
 }
 }
@@ -2275,7 +2275,7 @@ lot of {Linux} into your technology!!!"
 \url{https://lore.kernel.org/r/20090724001429.GA17374@linux.vnet.ibm.com}
 [Viewed August 15, 2009]"
 ,annotation={
-	First posting of simple and fast preemptable RCU.
+	First posting of simple and fast preemptible RCU.
 }
 }
 
@@ -2639,7 +2639,7 @@ lot of {Linux} into your technology!!!"
 	RCU-protected hash tables, barriers vs. read-side traversal order.
 	.
 	If the updater is making changes in the opposite direction from
-	the read-side traveral order, the updater need only execute a
+	the read-side traversal order, the updater need only execute a
 	memory-barrier instruction, but if in the same direction, the
 	updater needs to wait for a grace period between the individual
 	updates.

Documentation/RCU/UP.rst

@@ -107,7 +107,7 @@ UP systems, including PREEMPT SMP builds running on UP systems.
 
 Quick Quiz #3:
 	Why can't synchronize_rcu() return immediately on UP systems running
-	preemptable RCU?
+	preemptible RCU?
 
 .. _answer_quick_quiz_up:
 
@@ -143,7 +143,7 @@ Answer to Quick Quiz #2:
 
 Answer to Quick Quiz #3:
 	Why can't synchronize_rcu() return immediately on UP systems
-	running preemptable RCU?
+	running preemptible RCU?
 
 	Because some other task might have been preempted in the middle
 	of an RCU read-side critical section.  If synchronize_rcu()

Documentation/RCU/checklist.rst

@@ -70,7 +70,7 @@ over a rather long period of time, but improvements are always welcome!
 	can serve as rcu_read_lock_sched(), but is less readable and
 	prevents lockdep from detecting locking issues.
 
-	Please not that you *cannot* rely on code known to be built
+	Please note that you *cannot* rely on code known to be built
 	only in non-preemptible kernels.  Such code can and will break,
 	especially in kernels built with CONFIG_PREEMPT_COUNT=y.
 

Documentation/RCU/lockdep.rst

@@ -65,7 +65,7 @@ checking of rcu_dereference() primitives:
 	rcu_access_pointer(p):
 		Return the value of the pointer and omit all barriers,
 		but retain the compiler constraints that prevent duplicating
-		or coalescsing.  This is useful when testing the
+		or coalescing.  This is useful when testing the
 		value of the pointer itself, for example, against NULL.
 
 The rcu_dereference_check() check expression can be any boolean

Documentation/RCU/torture.rst

@@ -216,7 +216,7 @@ Kernel boot arguments can also be supplied, for example, to control
 rcutorture's module parameters.  For example, to test a change to RCU's
 CPU stall-warning code, use "--bootargs 'rcutorture.stall_cpu=30'".
 This will of course result in the scripting reporting a failure, namely
-the resuling RCU CPU stall warning.  As noted above, reducing memory may
+the resulting RCU CPU stall warning.  As noted above, reducing memory may
 require disabling rcutorture's callback-flooding tests::
 
 	kvm.sh --cpus 448 --configs '56*TREE04' --memory 128M \
@@ -370,5 +370,5 @@ You can also re-run a previous remote run in a manner similar to kvm.sh:
 		tools/testing/selftests/rcutorture/res/2022.11.03-11.26.28-remote \
 		--duration 24h
 
-In this case, most of the kvm-again.sh parmeters may be supplied following
+In this case, most of the kvm-again.sh parameters may be supplied following
 the pathname of the old run-results directory.

Documentation/RCU/whatisRCU.rst

@@ -597,10 +597,10 @@ to avoid having to write your own callback::
 If the occasional sleep is permitted, the single-argument form may
 be used, omitting the rcu_head structure from struct foo.
 
-	kfree_rcu(old_fp);
+	kfree_rcu_mightsleep(old_fp);
 
-This variant of kfree_rcu() almost never blocks, but might do so by
-invoking synchronize_rcu() in response to memory-allocation failure.
+This variant almost never blocks, but might do so by invoking
+synchronize_rcu() in response to memory-allocation failure.
 
 Again, see checklist.rst for additional rules governing the use of RCU.
 

drivers/block/drbd/drbd_nl.c

@@ -1615,7 +1615,7 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 			drbd_send_sync_param(peer_device);
 	}
 
-	kvfree_rcu(old_disk_conf);
+	kvfree_rcu_mightsleep(old_disk_conf);
 	kfree(old_plan);
 	mod_timer(&device->request_timer, jiffies + HZ);
 	goto success;
@@ -2446,7 +2446,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 
 	mutex_unlock(&connection->resource->conf_update);
 	mutex_unlock(&connection->data.mutex);
-	kvfree_rcu(old_net_conf);
+	kvfree_rcu_mightsleep(old_net_conf);
 
 	if (connection->cstate >= C_WF_REPORT_PARAMS) {
 		struct drbd_peer_device *peer_device;
@@ -2860,7 +2860,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 		new_disk_conf->disk_size = (sector_t)rs.resize_size;
 		rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
 		mutex_unlock(&device->resource->conf_update);
-		kvfree_rcu(old_disk_conf);
+		kvfree_rcu_mightsleep(old_disk_conf);
 		new_disk_conf = NULL;
 	}
 

drivers/block/drbd/drbd_receiver.c

@@ -3759,7 +3759,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in
 		drbd_info(connection, "peer data-integrity-alg: %s\n",
 			  integrity_alg[0] ? integrity_alg : "(none)");
 
-	kvfree_rcu(old_net_conf);
+	kvfree_rcu_mightsleep(old_net_conf);
 	return 0;
 
 disconnect_rcu_unlock:
@@ -4127,7 +4127,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 
 			rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
 			mutex_unlock(&connection->resource->conf_update);
-			kvfree_rcu(old_disk_conf);
+			kvfree_rcu_mightsleep(old_disk_conf);
 
 			drbd_info(device, "Peer sets u_size to %lu sectors (old: %lu)\n",
 				 (unsigned long)p_usize, (unsigned long)my_usize);

drivers/block/drbd/drbd_state.c

@@ -2071,7 +2071,7 @@ static int w_after_conn_state_ch(struct drbd_work *w, int unused)
 		conn_free_crypto(connection);
 		mutex_unlock(&connection->resource->conf_update);
 
-		kvfree_rcu(old_conf);
+		kvfree_rcu_mightsleep(old_conf);
 	}
 
 	if (ns_max.susp_fen) {

drivers/misc/vmw_vmci/vmci_context.c

@@ -687,7 +687,7 @@ int vmci_ctx_remove_notification(u32 context_id, u32 remote_cid)
 	spin_unlock(&context->lock);
 
 	if (notifier)
-		kvfree_rcu(notifier);
+		kvfree_rcu_mightsleep(notifier);
 
 	vmci_ctx_put(context);
 

drivers/misc/vmw_vmci/vmci_event.c

@@ -209,7 +209,7 @@ int vmci_event_unsubscribe(u32 sub_id)
 	if (!s)
 		return VMCI_ERROR_NOT_FOUND;
 
-	kvfree_rcu(s);
+	kvfree_rcu_mightsleep(s);
 
 	return VMCI_SUCCESS;
 }

drivers/net/ethernet/mellanox/mlx5/core/en/tc/int_port.c

@@ -242,7 +242,7 @@ mlx5e_int_port_remove(struct mlx5e_tc_int_port_priv *priv,
 		mlx5_del_flow_rules(int_port->rx_rule);
 	mapping_remove(ctx, int_port->mapping);
 	mlx5e_int_port_metadata_free(priv, int_port->match_metadata);
-	kfree_rcu(int_port);
+	kfree_rcu_mightsleep(int_port);
 	priv->num_ports--;
 }
 

drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c

@@ -670,7 +670,7 @@ static int mlx5e_macsec_del_txsa(struct macsec_context *ctx)
 
 	mlx5e_macsec_cleanup_sa(macsec, tx_sa, true);
 	mlx5_destroy_encryption_key(macsec->mdev, tx_sa->enc_key_id);
-	kfree_rcu(tx_sa);
+	kfree_rcu_mightsleep(tx_sa);
 	macsec_device->tx_sa[assoc_num] = NULL;
 
 out:
@@ -849,7 +849,7 @@ static void macsec_del_rxsc_ctx(struct mlx5e_macsec *macsec, struct mlx5e_macsec
 	xa_erase(&macsec->sc_xarray, rx_sc->sc_xarray_element->fs_id);
 	metadata_dst_free(rx_sc->md_dst);
 	kfree(rx_sc->sc_xarray_element);
-	kfree_rcu(rx_sc);
+	kfree_rcu_mightsleep(rx_sc);
 }
 
 static int mlx5e_macsec_del_rxsc(struct macsec_context *ctx)

fs/ext4/super.c

@@ -2500,7 +2500,7 @@ static void ext4_apply_quota_options(struct fs_context *fc,
 			qname = rcu_replace_pointer(sbi->s_qf_names[i], qname,
 						lockdep_is_held(&sb->s_umount));
 			if (qname)
-				kfree_rcu(qname);
+				kfree_rcu_mightsleep(qname);
 		}
 	}
 

include/linux/lockdep.h

@@ -134,7 +134,8 @@ struct held_lock {
 	unsigned int read:2;        /* see lock_acquire() comment */
 	unsigned int check:1;       /* see lock_acquire() comment */
 	unsigned int hardirqs_off:1;
-	unsigned int references:12;					/* 32 bits */
+	unsigned int sync:1;
+	unsigned int references:11;					/* 32 bits */
 	unsigned int pin_count;
 };
 
@@ -268,6 +269,10 @@ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 
 extern void lock_release(struct lockdep_map *lock, unsigned long ip);
 
+extern void lock_sync(struct lockdep_map *lock, unsigned int subclass,
+		      int read, int check, struct lockdep_map *nest_lock,
+		      unsigned long ip);
+
 /* lock_is_held_type() returns */
 #define LOCK_STATE_UNKNOWN	-1
 #define LOCK_STATE_NOT_HELD	0
@@ -554,6 +559,7 @@ do {									\
 #define lock_map_acquire_read(l)		lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
 #define lock_map_acquire_tryread(l)		lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
 #define lock_map_release(l)			lock_release(l, _THIS_IP_)
+#define lock_map_sync(l)			lock_sync(l, 0, 0, 1, NULL, _THIS_IP_)
 
 #ifdef CONFIG_PROVE_LOCKING
 # define might_lock(lock)						\

include/linux/notifier.h

@@ -73,6 +73,9 @@ struct raw_notifier_head {
 
 struct srcu_notifier_head {
 	struct mutex mutex;
+#ifdef CONFIG_TREE_SRCU
+	struct srcu_usage srcuu;
+#endif
 	struct srcu_struct srcu;
 	struct notifier_block __rcu *head;
 };
@@ -107,7 +110,7 @@ extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
 	{							\
 		.mutex = __MUTEX_INITIALIZER(name.mutex),	\
 		.head = NULL,					\
-		.srcu = __SRCU_STRUCT_INIT(name.srcu, pcpu),	\
+		.srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
 	}
 
 #define ATOMIC_NOTIFIER_HEAD(name)				\

include/linux/srcu.h

@@ -102,13 +102,43 @@ static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
 	return lock_is_held(&ssp->dep_map);
 }
 
+/*
+ * Annotations provide deadlock detection for SRCU.
+ *
+ * Similar to other lockdep annotations, except there is an additional
+ * srcu_lock_sync(), which is basically an empty *write*-side critical section,
+ * see lock_sync() for more information.
+ */
+
+/* Annotates a srcu_read_lock() */
+static inline void srcu_lock_acquire(struct lockdep_map *map)
+{
+	lock_map_acquire_read(map);
+}
+
+/* Annotates a srcu_read_lock() */
+static inline void srcu_lock_release(struct lockdep_map *map)
+{
+	lock_map_release(map);
+}
+
+/* Annotates a synchronize_srcu() */
+static inline void srcu_lock_sync(struct lockdep_map *map)
+{
+	lock_map_sync(map);
+}
+
 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
 static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
 {
 	return 1;
 }
 
+#define srcu_lock_acquire(m) do { } while (0)
+#define srcu_lock_release(m) do { } while (0)
+#define srcu_lock_sync(m) do { } while (0)
+
 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
 #define SRCU_NMI_UNKNOWN	0x0
@@ -182,7 +212,7 @@ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)
 
 	srcu_check_nmi_safety(ssp, false);
 	retval = __srcu_read_lock(ssp);
-	rcu_lock_acquire(&(ssp)->dep_map);
+	srcu_lock_acquire(&(ssp)->dep_map);
 	return retval;
 }
 
@@ -254,7 +284,7 @@ static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)
 {
 	WARN_ON_ONCE(idx & ~0x1);
 	srcu_check_nmi_safety(ssp, false);
-	rcu_lock_release(&(ssp)->dep_map);
+	srcu_lock_release(&(ssp)->dep_map);
 	__srcu_read_unlock(ssp, idx);
 }
 

include/linux/srcutiny.h

@@ -31,7 +31,7 @@ struct srcu_struct {
 
 void srcu_drive_gp(struct work_struct *wp);
 
-#define __SRCU_STRUCT_INIT(name, __ignored)				\
+#define __SRCU_STRUCT_INIT(name, __ignored, ___ignored)			\
 {									\
 	.srcu_wq = __SWAIT_QUEUE_HEAD_INITIALIZER(name.srcu_wq),	\
 	.srcu_cb_tail = &name.srcu_cb_head,				\
@@ -44,9 +44,9 @@ void srcu_drive_gp(struct work_struct *wp);
  * Tree SRCU, which needs some per-CPU data.
  */
 #define DEFINE_SRCU(name) \
-	struct srcu_struct name = __SRCU_STRUCT_INIT(name, name)
+	struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name)
 #define DEFINE_STATIC_SRCU(name) \
-	static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name)
+	static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name)
 
 void synchronize_srcu(struct srcu_struct *ssp);