[PATCH] srcu: Remove srcu_cblist_invoking member from sdp

[qiang . zhang]

From: Zqiang <qiang.zh...@windriver.com>

Workqueue can ensure the multiple same sdp->work sequential
execution in rcu_gp_wq, not need srcu_cblist_invoking to
prevent concurrent execution, so remove it.

Signed-off-by: Zqiang <qiang.zh...@windriver.com>
---
 include/linux/srcutree.h | 1 -
 kernel/rcu/srcutree.c    | 8 ++------
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
index 9cfcc8a756ae..62d8312b5451 100644
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -31,7 +31,6 @@ struct srcu_data {
        struct rcu_segcblist srcu_cblist;       /* List of callbacks.*/
        unsigned long srcu_gp_seq_needed;       /* Furthest future GP needed. */
        unsigned long srcu_gp_seq_needed_exp;   /* Furthest future exp GP. */
-       bool srcu_cblist_invoking;              /* Invoking these CBs? */
        struct timer_list delay_work;           /* Delay for CB invoking */
        struct work_struct work;                /* Context for CB invoking. */
        struct rcu_head srcu_barrier_head;      /* For srcu_barrier() use. */
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 3c5e2806e0b9..c4d5cd2567a6 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -134,7 +134,6 @@ static void init_srcu_struct_nodes(struct srcu_struct *ssp, 
bool is_static)
                sdp = per_cpu_ptr(ssp->sda, cpu);
                spin_lock_init(&ACCESS_PRIVATE(sdp, lock));
                rcu_segcblist_init(&sdp->srcu_cblist);
-               sdp->srcu_cblist_invoking = false;
                sdp->srcu_gp_seq_needed = ssp->srcu_gp_seq;
                sdp->srcu_gp_seq_needed_exp = ssp->srcu_gp_seq;
                sdp->mynode = &snp_first[cpu / levelspread[level]];
@@ -1254,14 +1253,11 @@ static void srcu_invoke_callbacks(struct work_struct 
*work)
        spin_lock_irq_rcu_node(sdp);
        rcu_segcblist_advance(&sdp->srcu_cblist,
                              rcu_seq_current(&ssp->srcu_gp_seq));
-       if (sdp->srcu_cblist_invoking ||
-           !rcu_segcblist_ready_cbs(&sdp->srcu_cblist)) {
+       if (!rcu_segcblist_ready_cbs(&sdp->srcu_cblist)) {
                spin_unlock_irq_rcu_node(sdp);
                return;  /* Someone else on the job or nothing to do. */
        }
 
-       /* We are on the job!  Extract and invoke ready callbacks. */
-       sdp->srcu_cblist_invoking = true;
        rcu_segcblist_extract_done_cbs(&sdp->srcu_cblist, &ready_cbs);
        len = ready_cbs.len;
        spin_unlock_irq_rcu_node(sdp);
@@ -1282,7 +1278,7 @@ static void srcu_invoke_callbacks(struct work_struct 
*work)
        rcu_segcblist_add_len(&sdp->srcu_cblist, -len);
        (void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
                                       rcu_seq_snap(&ssp->srcu_gp_seq));
-       sdp->srcu_cblist_invoking = false;
+
        more = rcu_segcblist_ready_cbs(&sdp->srcu_cblist);
        spin_unlock_irq_rcu_node(sdp);
        if (more)
-- 
2.17.1