block: misc updates to blk_get_queue()

* blk_get_queue() is peculiar in that it returns 0 on success and 1 on
  failure instead of 0 / -errno or boolean.  Update it such that it
  returns %true on success and %false on failure.

* Make sure the caller checks for the return value.

* Separate out __blk_get_queue() which doesn't check whether @q is
  dead and put it in blk.h.  This will be used later.

This patch doesn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 02e9fca80825..c958169d24f0 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -615,7 +615,7 @@ void add_disk(struct gendisk *disk)
          * Take an extra ref on queue which will be put on disk_release()
          * so that it sticks around as long as @disk is there.
          */
-        WARN_ON_ONCE(blk_get_queue(disk->queue));
+        WARN_ON_ONCE(!blk_get_queue(disk->queue));
 
         retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
                                    "bdi");