[PATCH v4 2/9] net: rds: use this_cpu_* per-cpu helper

[Shan Wei]

From: Shan Wei <davids...@tencent.com>


Signed-off-by: Shan Wei <davids...@tencent.com>
Reviewed-by: Christoph Lameter <c...@linux.com>
---
v4:
1. add missing __percpu annotations.
2. [read|write]ing fields of struct rds_ib_cache_head
using __this_cpu_* operation, drop per_cpu_ptr.
---
 net/rds/ib.h      |    2 +-
 net/rds/ib_recv.c |   24 +++++++++++++-----------
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/net/rds/ib.h b/net/rds/ib.h
index 8d2b3d5..7280ab8 100644
--- a/net/rds/ib.h
+++ b/net/rds/ib.h
@@ -50,7 +50,7 @@ struct rds_ib_cache_head {
 };
 
 struct rds_ib_refill_cache {
-       struct rds_ib_cache_head *percpu;
+       struct rds_ib_cache_head __percpu *percpu;
        struct list_head         *xfer;
        struct list_head         *ready;
 };
diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 8d19491..8c5bc85 100644
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -418,20 +418,21 @@ static void rds_ib_recv_cache_put(struct list_head 
*new_item,
                                 struct rds_ib_refill_cache *cache)
 {
        unsigned long flags;
-       struct rds_ib_cache_head *chp;
        struct list_head *old;
+       struct list_head __percpu *chpfirst;
 
        local_irq_save(flags);
 
-       chp = per_cpu_ptr(cache->percpu, smp_processor_id());
-       if (!chp->first)
+       chpfirst = __this_cpu_read(cache->percpu->first);
+       if (!chpfirst)
                INIT_LIST_HEAD(new_item);
        else /* put on front */
-               list_add_tail(new_item, chp->first);
-       chp->first = new_item;
-       chp->count++;
+               list_add_tail(new_item, chpfirst);
 
-       if (chp->count < RDS_IB_RECYCLE_BATCH_COUNT)
+       __this_cpu_write(chpfirst, new_item);
+       __this_cpu_inc(cache->percpu->count);
+
+       if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
                goto end;
 
        /*
@@ -443,12 +444,13 @@ static void rds_ib_recv_cache_put(struct list_head 
*new_item,
        do {
                old = xchg(&cache->xfer, NULL);
                if (old)
-                       list_splice_entire_tail(old, chp->first);
-               old = cmpxchg(&cache->xfer, NULL, chp->first);
+                       list_splice_entire_tail(old, chpfirst);
+               old = cmpxchg(&cache->xfer, NULL, chpfirst);
        } while (old);
 
-       chp->first = NULL;
-       chp->count = 0;
+
+       __this_cpu_write(chpfirst, NULL);
+       __this_cpu_write(cache->percpu->count, 0);
 end:
        local_irq_restore(flags);
 }
-- 
1.7.1


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