[PATCH net-next 02/10] net: sched: change tcf block offload counter type to atomic_t

[Vlad Buslov]

As a preparation for running proto ops functions without rtnl lock, change
offload counter type to atomic. This is necessary to allow updating the
counter by multiple concurrent users when offloading filters to hardware
from unlocked classifiers.

Signed-off-by: Vlad Buslov <vla...@mellanox.com>
Acked-by: Jiri Pirko <j...@mellanox.com>
---
 include/net/sch_generic.h | 7 ++++---
 net/sched/cls_api.c       | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index a3eaf5f9d28f..d778c502decd 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -14,6 +14,7 @@
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
+#include <linux/atomic.h>
 #include <net/gen_stats.h>
 #include <net/rtnetlink.h>
 #include <net/flow_offload.h>
@@ -401,7 +402,7 @@ struct tcf_block {
        struct flow_block flow_block;
        struct list_head owner_list;
        bool keep_dst;
-       unsigned int offloadcnt; /* Number of oddloaded filters */
+       atomic_t offloadcnt; /* Number of oddloaded filters */
        unsigned int nooffloaddevcnt; /* Number of devs unable to do offload */
        struct {
                struct tcf_chain *chain;
@@ -443,7 +444,7 @@ static inline void tcf_block_offload_inc(struct tcf_block 
*block, u32 *flags)
        if (*flags & TCA_CLS_FLAGS_IN_HW)
                return;
        *flags |= TCA_CLS_FLAGS_IN_HW;
-       block->offloadcnt++;
+       atomic_inc(&block->offloadcnt);
 }
 
 static inline void tcf_block_offload_dec(struct tcf_block *block, u32 *flags)
@@ -451,7 +452,7 @@ static inline void tcf_block_offload_dec(struct tcf_block 
*block, u32 *flags)
        if (!(*flags & TCA_CLS_FLAGS_IN_HW))
                return;
        *flags &= ~TCA_CLS_FLAGS_IN_HW;
-       block->offloadcnt--;
+       atomic_dec(&block->offloadcnt);
 }
 
 static inline void
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index a3b07c6e3f53..8502bd006b37 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -629,7 +629,7 @@ static void tc_indr_block_call(struct tcf_block *block,
 
 static bool tcf_block_offload_in_use(struct tcf_block *block)
 {
-       return block->offloadcnt;
+       return atomic_read(&block->offloadcnt);
 }
 
 static int tcf_block_offload_cmd(struct tcf_block *block,
-- 
2.21.0