[PATCH V7 3/4] softirq: Rewrite softirq processing loop

[qianjun . kernel]

From: jun qian <qianjun.ker...@gmail.com>

Simplify the softirq processing loop by using the bitmap APIs

Signed-off-by: jun qian <qianjun.ker...@gmail.com>
---
 kernel/softirq.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 5a627cd..cbb59b5 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -260,9 +260,9 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
        unsigned long old_flags = current->flags;
        unsigned int max_restart = MAX_SOFTIRQ_RESTART;
        struct softirq_action *h;
+       unsigned long pending;
+       unsigned int vec_nr;
        bool in_hardirq;
-       __u32 pending;
-       int softirq_bit;
 
        /*
         * Mask out PF_MEMALLOC as the current task context is borrowed for the
@@ -283,15 +283,13 @@ asmlinkage __visible void __softirq_entry 
__do_softirq(void)
 
        local_irq_enable();
 
-       h = softirq_vec;
-
-       while ((softirq_bit = ffs(pending))) {
-               unsigned int vec_nr;
+       for_each_set_bit(vec_nr, &pending, NR_SOFTIRQS) {
                int prev_count;
 
-               h += softirq_bit - 1;
+               __clear_bit(vec_nr, &pending);
+
+               h = softirq_vec + vec_nr;
 
-               vec_nr = h - softirq_vec;
                prev_count = preempt_count();
 
                kstat_incr_softirqs_this_cpu(vec_nr);
@@ -305,8 +303,6 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
                               prev_count, preempt_count());
                        preempt_count_set(prev_count);
                }
-               h++;
-               pending >>= softirq_bit;
        }
 
        if (__this_cpu_read(ksoftirqd) == current)
-- 
1.8.3.1