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| author | Jens Axboe <axboe@kernel.dk> | 2019-07-16 21:55:23 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-07-22 05:46:23 +0200 |
| commit | 893a1c97205a3ece0cbb3f571a3b972080f3b4c7 (patch) | |
| tree | 9173a99e83a6842a89b07fb7eeb26e816a0c8faa /include | |
| parent | io_uring: add a memory barrier before atomic_read (diff) | |
| download | linux-893a1c97205a3ece0cbb3f571a3b972080f3b4c7.tar.xz linux-893a1c97205a3ece0cbb3f571a3b972080f3b4c7.zip | |
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.h | 5 |
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) |