From: Hannes Reinecke <hare@suse.de>
Date: Tue, 24 May 2022 07:56:30 +0200
Subject: [PATCH] block: document BLK_STS_AGAIN usage
Git-commit: 98d40e76652e9aeb3aec4065f600d633ed335e94
Patch-mainline: v5.19-rc1
References: jsc#PED-1183

BLK_STS_AGAIN should only be used if RQF_NOWAIT is set and the bio
would block. So we'd better document that to avoid accidental misuse.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220524055631.85480-2-hare@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 include/linux/blk_types.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 40e815400611..8b38367d1bc7 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -105,6 +105,10 @@ typedef u16 blk_short_t;
 /* hack for device mapper, don't use elsewhere: */
 #define BLK_STS_DM_REQUEUE    ((__force blk_status_t)11)
 
+/*
+ * BLK_STS_AGAIN should only be returned if RQF_NOWAIT is set
+ * and the bio would block (cf bio_wouldblock_error())
+ */
 #define BLK_STS_AGAIN		((__force blk_status_t)12)
 
 /*
-- 
2.35.3