Merge branches 'doc.2022.10.18c', 'fixes.2022.10.18c', 'lazy.2022.10.18c', 'srcunmisafe.2022.10.18b', 'torture.2022.10.18c' and 'torturescript.2022.10.18c' into HEAD

doc.2022.10.18c: Documentation updates.
fixes.2022.10.18c: Miscellaneous fixes.
lazy.2022.10.18c: Lazy call_rcu() and NOCB updates.
srcunmisafe.2022.10.18b: NMI-safe SRCU readers.
torture.2022.10.18c: Torture-test updates.
torturescript.2022.10.18c: Torture-test scripting updates.

Author: paulmckrcu

arch/Kconfig

@@ -468,6 +468,9 @@ config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
 config ARCH_HAVE_NMI_SAFE_CMPXCHG
 	bool
 
+config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
+	bool
+
 config HAVE_ALIGNED_STRUCT_PAGE
 	bool
 	help

arch/arm64/Kconfig

@@ -31,6 +31,7 @@ config ARM64
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_KEEPINITRD
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
+	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PTE_DEVMAP
 	select ARCH_HAS_PTE_SPECIAL

arch/loongarch/Kconfig

@@ -10,6 +10,7 @@ config LOONGARCH
 	select ARCH_ENABLE_MEMORY_HOTPLUG
 	select ARCH_ENABLE_MEMORY_HOTREMOVE
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
+	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_INLINE_READ_LOCK if !PREEMPTION

arch/s390/Kconfig

@@ -73,6 +73,7 @@ config S390
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MEM_ENCRYPT
+	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SCALED_CPUTIME
 	select ARCH_HAS_SET_MEMORY

arch/x86/Kconfig

@@ -81,6 +81,7 @@ config X86
 	select ARCH_HAS_KCOV			if X86_64
 	select ARCH_HAS_MEM_ENCRYPT
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
+	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PMEM_API		if X86_64
 	select ARCH_HAS_PTE_DEVMAP		if X86_64

drivers/scsi/scsi_error.c

@@ -312,7 +312,7 @@ void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
 	 * Ensure that all tasks observe the host state change before the
 	 * host_failed change.
 	 */
-	call_rcu(&scmd->rcu, scsi_eh_inc_host_failed);
+	call_rcu_flush(&scmd->rcu, scsi_eh_inc_host_failed);
 }
 
 /**

include/linux/kvm_host.h

@@ -416,7 +416,7 @@ static __always_inline void guest_context_enter_irqoff(void)
 	 */
 	if (!context_tracking_guest_enter()) {
 		instrumentation_begin();
-		rcu_virt_note_context_switch(smp_processor_id());
+		rcu_virt_note_context_switch();
 		instrumentation_end();
 	}
 }

include/linux/rcupdate.h

@@ -108,6 +108,15 @@ static inline int rcu_preempt_depth(void)
 
 #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
 
+#ifdef CONFIG_RCU_LAZY
+void call_rcu_flush(struct rcu_head *head, rcu_callback_t func);
+#else
+static inline void call_rcu_flush(struct rcu_head *head, rcu_callback_t func)
+{
+	call_rcu(head, func);
+}
+#endif
+
 /* Internal to kernel */
 void rcu_init(void);
 extern int rcu_scheduler_active;

include/linux/rcutiny.h

@@ -142,12 +142,10 @@ static inline int rcu_needs_cpu(void)
  * Take advantage of the fact that there is only one CPU, which
  * allows us to ignore virtualization-based context switches.
  */
-static inline void rcu_virt_note_context_switch(int cpu) { }
+static inline void rcu_virt_note_context_switch(void) { }
 static inline void rcu_cpu_stall_reset(void) { }
 static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; }
 static inline void rcu_irq_exit_check_preempt(void) { }
-#define rcu_is_idle_cpu(cpu) \
-	(is_idle_task(current) && !in_nmi() && !in_hardirq() && !in_serving_softirq())
 static inline void exit_rcu(void) { }
 static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t)
 {

include/linux/rcutree.h

@@ -27,7 +27,7 @@ void rcu_cpu_stall_reset(void);
  * wrapper around rcu_note_context_switch(), which allows TINY_RCU
  * to save a few bytes. The caller must have disabled interrupts.
  */
-static inline void rcu_virt_note_context_switch(int cpu)
+static inline void rcu_virt_note_context_switch(void)
 {
 	rcu_note_context_switch(false);
 }
@@ -87,8 +87,6 @@ bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
 void cond_synchronize_rcu(unsigned long oldstate);
 void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
 
-bool rcu_is_idle_cpu(int cpu);
-
 #ifdef CONFIG_PROVE_RCU
 void rcu_irq_exit_check_preempt(void);
 #else