[PATCH] rdma: delete the useless casting value returned

[PATCH] rdma: delete the useless casting value returned

[Wang Qing]

Fix the following coccicheck warning:
WARNING: casting value returned by memory allocation function is useless.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 include/rdma/ib_verbs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index ca28fca..f4d24d8
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -2259,7 +2259,7 @@ struct iw_cm_conn_param;
 				      struct ib_struct)))
 
 #define rdma_zalloc_drv_obj_gfp(ib_dev, ib_type, gfp)                         \
-	((struct ib_type *)kzalloc(ib_dev->ops.size_##ib_type, gfp))
+	kzalloc(ib_dev->ops.size_##ib_type, gfp)
 
 #define rdma_zalloc_drv_obj(ib_dev, ib_type)                                   \
 	rdma_zalloc_drv_obj_gfp(ib_dev, ib_type, GFP_KERNEL)
-- 
2.7.4

Re: [PATCH] rdma: delete the useless casting value returned

[Jason Gunthorpe]

On Fri, Mar 12, 2021 at 10:19:30AM +0800, Wang Qing wrote:
> Fix the following coccicheck warning:
> WARNING: casting value returned by memory allocation function is useless.

This warning is wrong in this specific case.

The #define is creating a helper function that enforces strict type
safety on the user

So eg,

  struct bar *obj = rdma_zalloc_drv_obj(ibdev, ib_ah);

Will fail to compile because 'obj' is not the required ib_ah type

Jason