[dm-devel] [PATCH RFC 4/7] block: define blk_qc_t as uintptr_t

[Jeffle Xu]

To support iopoll for bio-based device, the returned cookie is actually
a pointer to an implementation specific object, e.g. an object
maintaining all split bios.

In such case, blk_qc_t should be large enough to contain one pointer,
for which uintptr_t is used here. Since uintptr_t is actually an integer
type in essence, there's no need of type casting in the original mq
path, while type casting is indeed needed in bio-based routine.

Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
---
 include/linux/types.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/types.h b/include/linux/types.h
index da5ca7e1bea9..f6301014a459 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -126,7 +126,7 @@ typedef u64 sector_t;
 typedef u64 blkcnt_t;
 
 /* cookie used for IO polling */
-typedef unsigned int blk_qc_t;
+typedef uintptr_t blk_qc_t;
 
 /*
  * The type of an index into the pagecache.
-- 
2.27.0