srcu: Renaming in preparation for additional reader flavor

Currently, there are only two flavors of readers, normal and NMI-safe.
A number of fields, functions, and types reflect this restriction.
This renaming-only commit prepares for the addition of light-weight
(as in memory-barrier-free) readers.  OK, OK, there is also a drive-by
white-space fixeup!

Signed-off-by: Paul E. McKenney <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: <[email protected]>
Reviewed-by: Neeraj Upadhyay <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>

Author: paulmckrcu

include/linux/srcu.h

@@ -181,10 +181,9 @@ static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
 #define SRCU_NMI_SAFE		0x2
 
 #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TREE_SRCU)
-void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe);
+void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);
 #else
-static inline void srcu_check_nmi_safety(struct srcu_struct *ssp,
-					 bool nmi_safe) { }
+static inline void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor) { }
 #endif
 
 
@@ -245,7 +244,7 @@ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)
 {
 	int retval;
 
-	srcu_check_nmi_safety(ssp, false);
+	srcu_check_read_flavor(ssp, false);
 	retval = __srcu_read_lock(ssp);
 	srcu_lock_acquire(&ssp->dep_map);
 	return retval;
@@ -262,7 +261,7 @@ static inline int srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp
 {
 	int retval;
 
-	srcu_check_nmi_safety(ssp, true);
+	srcu_check_read_flavor(ssp, true);
 	retval = __srcu_read_lock_nmisafe(ssp);
 	rcu_try_lock_acquire(&ssp->dep_map);
 	return retval;
@@ -274,7 +273,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
 {
 	int retval;
 
-	srcu_check_nmi_safety(ssp, false);
+	srcu_check_read_flavor(ssp, false);
 	retval = __srcu_read_lock(ssp);
 	return retval;
 }
@@ -303,7 +302,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
 static inline int srcu_down_read(struct srcu_struct *ssp) __acquires(ssp)
 {
 	WARN_ON_ONCE(in_nmi());
-	srcu_check_nmi_safety(ssp, false);
+	srcu_check_read_flavor(ssp, false);
 	return __srcu_read_lock(ssp);
 }
 
@@ -318,7 +317,7 @@ static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)
 	__releases(ssp)
 {
 	WARN_ON_ONCE(idx & ~0x1);
-	srcu_check_nmi_safety(ssp, false);
+	srcu_check_read_flavor(ssp, false);
 	srcu_lock_release(&ssp->dep_map);
 	__srcu_read_unlock(ssp, idx);
 }
@@ -334,7 +333,7 @@ static inline void srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx)
 	__releases(ssp)
 {
 	WARN_ON_ONCE(idx & ~0x1);
-	srcu_check_nmi_safety(ssp, true);
+	srcu_check_read_flavor(ssp, true);
 	rcu_lock_release(&ssp->dep_map);
 	__srcu_read_unlock_nmisafe(ssp, idx);
 }
@@ -343,7 +342,7 @@ static inline void srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx)
 static inline notrace void
 srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
 {
-	srcu_check_nmi_safety(ssp, false);
+	srcu_check_read_flavor(ssp, false);
 	__srcu_read_unlock(ssp, idx);
 }
 
@@ -360,7 +359,7 @@ static inline void srcu_up_read(struct srcu_struct *ssp, int idx)
 {
 	WARN_ON_ONCE(idx & ~0x1);
 	WARN_ON_ONCE(in_nmi());
-	srcu_check_nmi_safety(ssp, false);
+	srcu_check_read_flavor(ssp, false);
 	__srcu_read_unlock(ssp, idx);
 }
 

include/linux/srcutree.h

@@ -25,7 +25,7 @@ struct srcu_data {
 	/* Read-side state. */
 	atomic_long_t srcu_lock_count[2];	/* Locks per CPU. */
 	atomic_long_t srcu_unlock_count[2];	/* Unlocks per CPU. */
-	int srcu_nmi_safety;			/* NMI-safe srcu_struct structure? */
+	int srcu_reader_flavor;			/* Reader flavor for srcu_struct structure? */
 
 	/* Update-side state. */
 	spinlock_t __private lock ____cacheline_internodealigned_in_smp;

kernel/rcu/srcutree.c

@@ -460,7 +460,7 @@ static unsigned long srcu_readers_unlock_idx(struct srcu_struct *ssp, int idx)
 
 		sum += atomic_long_read(&cpuc->srcu_unlock_count[idx]);
 		if (IS_ENABLED(CONFIG_PROVE_RCU))
-			mask = mask | READ_ONCE(cpuc->srcu_nmi_safety);
+			mask = mask | READ_ONCE(cpuc->srcu_reader_flavor);
 	}
 	WARN_ONCE(IS_ENABLED(CONFIG_PROVE_RCU) && (mask & (mask >> 1)),
 		  "Mixed NMI-safe readers for srcu_struct at %ps.\n", ssp);
@@ -699,25 +699,25 @@ EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
 
 #ifdef CONFIG_PROVE_RCU
 /*
- * Check for consistent NMI safety.
+ * Check for consistent reader flavor.
  */
-void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe)
+void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor)
 {
-	int nmi_safe_mask = 1 << nmi_safe;
-	int old_nmi_safe_mask;
+	int reader_flavor_mask = 1 << read_flavor;
+	int old_reader_flavor_mask;
 	struct srcu_data *sdp;
 
 	/* NMI-unsafe use in NMI is a bad sign */
-	WARN_ON_ONCE(!nmi_safe && in_nmi());
+	WARN_ON_ONCE(!read_flavor && in_nmi());
 	sdp = raw_cpu_ptr(ssp->sda);
-	old_nmi_safe_mask = READ_ONCE(sdp->srcu_nmi_safety);
-	if (!old_nmi_safe_mask) {
-		WRITE_ONCE(sdp->srcu_nmi_safety, nmi_safe_mask);
+	old_reader_flavor_mask = READ_ONCE(sdp->srcu_reader_flavor);
+	if (!old_reader_flavor_mask) {
+		WRITE_ONCE(sdp->srcu_reader_flavor, reader_flavor_mask);
 		return;
 	}
-	WARN_ONCE(old_nmi_safe_mask != nmi_safe_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_nmi_safe_mask, nmi_safe_mask);
+	WARN_ONCE(old_reader_flavor_mask != reader_flavor_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_reader_flavor_mask, reader_flavor_mask);
 }
-EXPORT_SYMBOL_GPL(srcu_check_nmi_safety);
+EXPORT_SYMBOL_GPL(srcu_check_read_flavor);
 #endif /* CONFIG_PROVE_RCU */
 
 /*