[PATCHv3 2/4] block: introduce rq_list_for_each_safe macro

[Keith Busch]

While iterating a list, a particular request may need to be removed for
special handling. Provide an iterator that can safely handle that.

Reviewed-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Keith Busch <kbusch at kernel.org>
---
 include/linux/blk-mq.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index bf64b94cd64e..1467f0fa2142 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -242,6 +242,10 @@ static inline unsigned short req_get_ioprio(struct request *req)
 #define rq_list_for_each(listptr, pos)			\
 	for (pos = rq_list_peek((listptr)); pos; pos = rq_list_next(pos))
 
+#define rq_list_for_each_safe(listptr, pos, nxt)			\
+	for (pos = rq_list_peek((listptr)), nxt = rq_list_next(pos);	\
+		pos; pos = nxt, nxt = pos ? rq_list_next(pos) : NULL)
+
 #define rq_list_next(rq)	(rq)->rq_next
 #define rq_list_empty(list)	((list) == (struct request *) NULL)
 
-- 
2.25.4