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authorJens Axboe <axboe@kernel.dk>2019-07-16 13:55:23 -0600
committerJens Axboe <axboe@kernel.dk>2019-07-21 21:46:23 -0600
commit893a1c97205a3ece0cbb3f571a3b972080f3b4c7 (patch)
tree9173a99e83a6842a89b07fb7eeb26e816a0c8faa /include
parentc0e48f9dea9129aa11bec3ed13803bcc26e96e49 (diff)
downloadlinux-893a1c97205a3ece0cbb3f571a3b972080f3b4c7.tar.bz2
blk-mq: allow REQ_NOWAIT to return an error inline
By default, if a caller sets REQ_NOWAIT and we need to block, we'll return -EAGAIN through the bio->bi_end_io() callback. For some use cases, this makes it hard to use. Allow a caller to ask for inline return of errors related to blocking by also setting REQ_NOWAIT_INLINE. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
-rw-r--r--include/linux/blk_types.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index feff3fe4467e..1b1fa1557e68 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -311,6 +311,7 @@ enum req_flag_bits {
__REQ_RAHEAD, /* read ahead, can fail anytime */
__REQ_BACKGROUND, /* background IO */
__REQ_NOWAIT, /* Don't wait if request will block */
+ __REQ_NOWAIT_INLINE, /* Return would-block error inline */
/*
* When a shared kthread needs to issue a bio for a cgroup, doing
* so synchronously can lead to priority inversions as the kthread
@@ -345,6 +346,7 @@ enum req_flag_bits {
#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
#define REQ_BACKGROUND (1ULL << __REQ_BACKGROUND)
#define REQ_NOWAIT (1ULL << __REQ_NOWAIT)
+#define REQ_NOWAIT_INLINE (1ULL << __REQ_NOWAIT_INLINE)
#define REQ_CGROUP_PUNT (1ULL << __REQ_CGROUP_PUNT)
#define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP)
@@ -418,12 +420,13 @@ static inline int op_stat_group(unsigned int op)
typedef unsigned int blk_qc_t;
#define BLK_QC_T_NONE -1U
+#define BLK_QC_T_EAGAIN -2U
#define BLK_QC_T_SHIFT 16
#define BLK_QC_T_INTERNAL (1U << 31)
static inline bool blk_qc_t_valid(blk_qc_t cookie)
{
- return cookie != BLK_QC_T_NONE;
+ return cookie != BLK_QC_T_NONE && cookie != BLK_QC_T_EAGAIN;
}
static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)