net: rds: fix per-cpu helper usage

commit ae4b46e9d "net: rds: use this_cpu_* per-cpu helper" broke per-cpu
handling for rds. chpfirst is the result of __this_cpu_read(), so it is
an absolute pointer and not __percpu. Therefore, __this_cpu_write()
should not operate on chpfirst, but rather on cache->percpu->first, just
like __this_cpu_read() did before.

Cc: <stable@vger.kernel.org> # 3.8+
Signed-off-byd Gerald Schaefer <gerald.schaefer@de.ibm.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 8eb9501..b7ebe23 100644 (file)
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -421,8 +421,7 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
                                 struct rds_ib_refill_cache *cache)
 {
        unsigned long flags;
-       struct list_head *old;
-       struct list_head __percpu *chpfirst;
+       struct list_head *old, *chpfirst;
 
        local_irq_save(flags);
 
@@ -432,7 +431,7 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
        else /* put on front */
                list_add_tail(new_item, chpfirst);
 
-       __this_cpu_write(chpfirst, new_item);
+       __this_cpu_write(cache->percpu->first, new_item);
        __this_cpu_inc(cache->percpu->count);
 
        if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
@@ -452,7 +451,7 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
        } while (old);
 
 
-       __this_cpu_write(chpfirst, NULL);
+       __this_cpu_write(cache->percpu->first, NULL);
        __this_cpu_write(cache->percpu->count, 0);
 end:
        local_irq_restore(flags);