[PATCH rcu 2/9] rcu: rename PREEMPT_AUTO to PREEMPT_LAZY

[Paul E. McKenney]

From: Ankur Arora <ankur.a.ar...@oracle.com>

Replace mentions of PREEMPT_AUTO with PREEMPT_LAZY.

Also, since PREMPT_LAZY implies PREEMPTION, we can reduce the
TASKS_RCU selection criteria from:

  NEED_TASKS_RCU && (PREEMPTION || PREEMPT_AUTO)
to:
  NEED_TASKS_RCU && PREEMPTION

CC: Paul E. McKenney <paul...@kernel.org>
Reviewed-by: Frederic Weisbecker <frede...@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Signed-off-by: Ankur Arora <ankur.a.ar...@oracle.com>
Signed-off-by: Paul E. McKenney <paul...@kernel.org>
---
 include/linux/srcutiny.h |  2 +-
 kernel/rcu/Kconfig       |  2 +-
 kernel/rcu/srcutiny.c    | 14 +++++++-------
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h
index 1321da803274d..31b59b4be2a74 100644
--- a/include/linux/srcutiny.h
+++ b/include/linux/srcutiny.h
@@ -64,7 +64,7 @@ static inline int __srcu_read_lock(struct srcu_struct *ssp)
 {
        int idx;
 
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        idx = ((READ_ONCE(ssp->srcu_idx) + 1) & 0x2) >> 1;
        WRITE_ONCE(ssp->srcu_lock_nesting[idx], 
READ_ONCE(ssp->srcu_lock_nesting[idx]) + 1);
        preempt_enable();
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index 2bb22dac3b5a9..582d461c9ab7d 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -91,7 +91,7 @@ config NEED_TASKS_RCU
 
 config TASKS_RCU
        bool
-       default NEED_TASKS_RCU && (PREEMPTION || PREEMPT_AUTO)
+       default NEED_TASKS_RCU && PREEMPTION
        select IRQ_WORK
 
 config FORCE_TASKS_RUDE_RCU
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 4dcbf8aa80ff7..f688bdad293ed 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -98,7 +98,7 @@ void __srcu_read_unlock(struct srcu_struct *ssp, int idx)
 {
        int newval;
 
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        newval = READ_ONCE(ssp->srcu_lock_nesting[idx]) - 1;
        WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);
        preempt_enable();
@@ -120,7 +120,7 @@ void srcu_drive_gp(struct work_struct *wp)
        struct srcu_struct *ssp;
 
        ssp = container_of(wp, struct srcu_struct, srcu_work);
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        if (ssp->srcu_gp_running || ULONG_CMP_GE(ssp->srcu_idx, 
READ_ONCE(ssp->srcu_idx_max))) {
                preempt_enable();
                return; /* Already running or nothing to do. */
@@ -138,7 +138,7 @@ void srcu_drive_gp(struct work_struct *wp)
        WRITE_ONCE(ssp->srcu_gp_waiting, true);  /* srcu_read_unlock() wakes! */
        preempt_enable();
        swait_event_exclusive(ssp->srcu_wq, 
!READ_ONCE(ssp->srcu_lock_nesting[idx]));
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        WRITE_ONCE(ssp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */
        WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1);
        preempt_enable();
@@ -159,7 +159,7 @@ void srcu_drive_gp(struct work_struct *wp)
         * at interrupt level, but the ->srcu_gp_running checks will
         * straighten that out.
         */
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        WRITE_ONCE(ssp->srcu_gp_running, false);
        idx = ULONG_CMP_LT(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max));
        preempt_enable();
@@ -172,7 +172,7 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
 {
        unsigned long cookie;
 
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        cookie = get_state_synchronize_srcu(ssp);
        if (ULONG_CMP_GE(READ_ONCE(ssp->srcu_idx_max), cookie)) {
                preempt_enable();
@@ -199,7 +199,7 @@ void call_srcu(struct srcu_struct *ssp, struct rcu_head 
*rhp,
 
        rhp->func = func;
        rhp->next = NULL;
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        local_irq_save(flags);
        *ssp->srcu_cb_tail = rhp;
        ssp->srcu_cb_tail = &rhp->next;
@@ -261,7 +261,7 @@ unsigned long start_poll_synchronize_srcu(struct 
srcu_struct *ssp)
 {
        unsigned long ret;
 
-       preempt_disable();  // Needed for PREEMPT_AUTO
+       preempt_disable();  // Needed for PREEMPT_LAZY
        ret = get_state_synchronize_srcu(ssp);
        srcu_gp_start_if_needed(ssp);
        preempt_enable();
-- 
2.40.1