[PATCH v2] blk-mq: fix incorrect blk_status_t casts

[Vasily Averin <vvs@openvz.org>]

Fixes sparse warnings:
block/blk-mq.c:1163:36: sparse:
 warning: cast from restricted blk_status_t
block/blk-mq.c:1251:17: sparse:
 warning: cast to restricted blk_status_t

blk_status_t type is bitwaise and requires __force for any casts.

Signed-off-by: Vasily Averin <vvs@openvz.org>
---
v2: introduced request_blk_status_en/decode helpers
	thanks Christoph Hellwig for the hint
---
 block/blk-mq.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 84d749511f55..8f067b021af3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1151,6 +1151,16 @@ void blk_mq_start_request(struct request *rq)
 }
 EXPORT_SYMBOL(blk_mq_start_request);
 
+static void *request_blk_status_encode(blk_status_t status)
+{
+	return (void *)(__force uintptr_t)status;
+}
+
+static blk_status_t request_blk_status_decode(void *ptr)
+{
+	return (__force blk_status_t)(uintptr_t)ptr;
+}
+
 /**
  * blk_end_sync_rq - executes a completion event on a request
  * @rq: request to complete
@@ -1160,7 +1170,7 @@ static void blk_end_sync_rq(struct request *rq, blk_status_t error)
 {
 	struct completion *waiting = rq->end_io_data;
 
-	rq->end_io_data = (void *)(uintptr_t)error;
+	rq->end_io_data = request_blk_status_encode(error);
 
 	/*
 	 * complete last, if this is a stack request the process (and thus
@@ -1228,6 +1238,7 @@ static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
  *    for execution and wait for completion.
  * Return: The blk_status_t result provided to blk_mq_end_request().
  */
+
 blk_status_t blk_execute_rq(struct request *rq, bool at_head)
 {
 	DECLARE_COMPLETION_ONSTACK(wait);
@@ -1248,7 +1259,7 @@ blk_status_t blk_execute_rq(struct request *rq, bool at_head)
 	else
 		wait_for_completion_io(&wait);
 
-	return (blk_status_t)(uintptr_t)rq->end_io_data;
+	return request_blk_status_decode(rq->end_io_data);
 }
 EXPORT_SYMBOL(blk_execute_rq);
 
-- 
2.31.1