block: Add fallthrough markers to switch statements

This patch suppresses gcc 7 warnings about falling through in switch
statements when building with W=1. From the gcc documentation: The
-Wimplicit-fallthrough=3 warning is enabled by -Wextra. See also
https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Warning-Options.html.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 4 insertions, 1 deletions

diff --git a/block/badblocks.c b/block/badblocks.c
index 6ebcef282314..43c71166e1e2 100644
--- a/block/badblocks.c
+++ b/block/badblocks.c
@@ -533,6 +533,7 @@ ssize_t badblocks_store(struct badblocks *bb, const char *page, size_t len,
         case 3:
                 if (newline != '\n')
                         return -EINVAL;
+                /* fall through */
         case 2:
                 if (length <= 0)
                         return -EINVAL;
diff --git a/block/elevator.c b/block/elevator.c
index dac99fbfc273..4bb2f0c93fa6 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -681,6 +681,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
                  */
                 if (elv_attempt_insert_merge(q, rq))
                         break;
+                /* fall through */
         case ELEVATOR_INSERT_SORT:
                 BUG_ON(blk_rq_is_passthrough(rq));
                 rq->rq_flags |= RQF_SORTED;
diff --git a/block/ioprio.c b/block/ioprio.c
index 4b120c9cf7e8..6f5d0b6625e3 100644
--- a/block/ioprio.c
+++ b/block/ioprio.c
@@ -75,7 +75,8 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
                 case IOPRIO_CLASS_RT:
                         if (!capable(CAP_SYS_ADMIN))
                                 return -EPERM;
-                        /* fall through, rt has prio field too */
+                        /* fall through */
+                        /* rt has prio field too */
                 case IOPRIO_CLASS_BE:
                         if (data >= IOPRIO_BE_NR || data < 0)
                                 return -EINVAL;