block: fix warning on compile with CONFIG_BLOCK

struct io_context was not defined, just add an empty forward decl.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 71e7a847df..e18d4192f6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -825,6 +825,7 @@ static inline void exit_io_context(void)
 {
 }
 
+struct io_context;
 static inline int put_io_context(struct io_context *ioc)
 {
         return 1;