Re: [PATCH v2] rtrs-clt: silence kbuild test inconsistent intenting smatch warning

[Bart Van Assche <bvanassche@xxxxxxx>]

On 2020-05-19 04:29, Danil Kipnis wrote:
> Kbuild test robot reports a smatch warning:
> drivers/infiniband/ulp/rtrs/rtrs-clt.c:1196 rtrs_clt_failover_req() warn: inconsistent indenting
> drivers/infiniband/ulp/rtrs/rtrs-clt.c:2890 rtrs_clt_request() warn: inconsistent indenting
> 
> To get rid of the warning, move the while_each_path() macro to a newline.
> Rename the macro to end_each_path() to avoid the "while should follow close
> brace '}'" checkpatch error.
> 
> Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
> 
> Signed-off-by: Danil Kipnis <danil.kipnis@xxxxxxxxxxxxxxx>
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> ---
>  v1->v2 Add fixes line
>  drivers/infiniband/ulp/rtrs/rtrs-clt.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> index 468fdd0d8713..0fa3a229d90e 100644
> --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> @@ -734,7 +734,7 @@ struct path_it {
>  			  (it)->i < (it)->clt->paths_num;		\
>  	     (it)->i++)
>  
> -#define while_each_path(it)						\
> +#define end_each_path(it)						\
>  	path_it_deinit(it);						\
>  	rcu_read_unlock();						\
>  	}
> @@ -1193,7 +1193,8 @@ static int rtrs_clt_failover_req(struct rtrs_clt *clt,
>  		/* Success path */
>  		rtrs_clt_inc_failover_cnt(alive_sess->stats);
>  		break;
> -	} while_each_path(&it);
> +	}
> +	end_each_path(&it);
>  
>  	return err;
>  }
> @@ -2887,7 +2888,8 @@ int rtrs_clt_request(int dir, struct rtrs_clt_req_ops *ops,
>  		}
>  		/* Success path */
>  		break;
> -	} while_each_path(&it);
> +	}
> +	end_each_path(&it);
>  
>  	return err;
>  }

I don't like the do_each_path() and end_each_path() macros because these do not
follow the pattern that is used elsewhere in the kernel to use a single macro
to iterate over a custom container. Has it been considered to combine these two
macros into a single macro, e.g. something like the following (untested) patch?


Subject: [PATCH] Combine while_each_path() and do_each_path() into
 for_each_path()

---
 drivers/infiniband/ulp/rtrs/rtrs-clt.c | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 468fdd0d8713..8dfa56dc32bc 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -727,18 +727,13 @@ struct path_it {
 	struct rtrs_clt_sess *(*next_path)(struct path_it *it);
 };

-#define do_each_path(path, clt, it) {					\
-	path_it_init(it, clt);						\
-	rcu_read_lock();						\
-	for ((it)->i = 0; ((path) = ((it)->next_path)(it)) &&		\
-			  (it)->i < (it)->clt->paths_num;		\
+#define for_each_path(path, clt, it)					\
+	for (path_it_init((it), (clt)), rcu_read_lock(), (it)->i = 0;	\
+	     (((path) = ((it)->next_path)(it)) &&			\
+	      (it)->i < (it)->clt->paths_num) ||			\
+		     (path_it_deinit(it), rcu_read_unlock(), 0);	\
 	     (it)->i++)

-#define while_each_path(it)						\
-	path_it_deinit(it);						\
-	rcu_read_unlock();						\
-	}
-
 /**
  * list_next_or_null_rr_rcu - get next list element in round-robin fashion.
  * @head:	the head for the list.
@@ -1177,7 +1172,7 @@ static int rtrs_clt_failover_req(struct rtrs_clt *clt,
 	int err = -ECONNABORTED;
 	struct path_it it;

-	do_each_path(alive_sess, clt, &it) {
+	for_each_path(alive_sess, clt, &it) {
 		if (unlikely(READ_ONCE(alive_sess->state) !=
 			     RTRS_CLT_CONNECTED))
 			continue;
@@ -1193,7 +1188,7 @@ static int rtrs_clt_failover_req(struct rtrs_clt *clt,
 		/* Success path */
 		rtrs_clt_inc_failover_cnt(alive_sess->stats);
 		break;
-	} while_each_path(&it);
+	}

 	return err;
 }
@@ -2862,7 +2857,7 @@ int rtrs_clt_request(int dir, struct rtrs_clt_req_ops *ops,
 		dma_dir = DMA_TO_DEVICE;
 	}

-	do_each_path(sess, clt, &it) {
+	for_each_path(sess, clt, &it) {
 		if (unlikely(READ_ONCE(sess->state) != RTRS_CLT_CONNECTED))
 			continue;

@@ -2887,7 +2882,7 @@ int rtrs_clt_request(int dir, struct rtrs_clt_req_ops *ops,
 		}
 		/* Success path */
 		break;
-	} while_each_path(&it);
+	}

 	return err;
 }