block: use the same failfast bits for bio and request
bio and request use the same set of failfast bits. This patch makes
the following changes to simplify things.
* enumify BIO_RW* bits and reorder bits such that BIOS_RW_FAILFAST_*
bits coincide with __REQ_FAILFAST_* bits.
* The above pushes BIO_RW_AHEAD out of sync with __REQ_FAILFAST_DEV
but the matching is useless anyway. init_request_from_bio() is
responsible for setting FAILFAST bits on FS requests and non-FS
requests never use BIO_RW_AHEAD. Drop the code and comment from
blk_rq_bio_prep().
* Define REQ_FAILFAST_MASK which is OR of all FAILFAST bits and
simplify FAILFAST flags handling in init_request_from_bio().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 2892b71..a299ed3 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -142,37 +142,40 @@
*
* bit 0 -- data direction
* If not set, bio is a read from device. If set, it's a write to device.
- * bit 1 -- rw-ahead when set
- * bit 2 -- barrier
+ * bit 1 -- fail fast device errors
+ * bit 2 -- fail fast transport errors
+ * bit 3 -- fail fast driver errors
+ * bit 4 -- rw-ahead when set
+ * bit 5 -- barrier
* Insert a serialization point in the IO queue, forcing previously
* submitted IO to be completed before this one is issued.
- * bit 3 -- synchronous I/O hint.
- * bit 4 -- Unplug the device immediately after submitting this bio.
- * bit 5 -- metadata request
+ * bit 6 -- synchronous I/O hint.
+ * bit 7 -- Unplug the device immediately after submitting this bio.
+ * bit 8 -- metadata request
* Used for tracing to differentiate metadata and data IO. May also
* get some preferential treatment in the IO scheduler
- * bit 6 -- discard sectors
+ * bit 9 -- discard sectors
* Informs the lower level device that this range of sectors is no longer
* used by the file system and may thus be freed by the device. Used
* for flash based storage.
- * bit 7 -- fail fast device errors
- * bit 8 -- fail fast transport errors
- * bit 9 -- fail fast driver errors
* Don't want driver retries for any fast fail whatever the reason.
* bit 10 -- Tell the IO scheduler not to wait for more requests after this
one has been submitted, even if it is a SYNC request.
*/
-#define BIO_RW 0 /* Must match RW in req flags (blkdev.h) */
-#define BIO_RW_AHEAD 1 /* Must match FAILFAST in req flags */
-#define BIO_RW_BARRIER 2
-#define BIO_RW_SYNCIO 3
-#define BIO_RW_UNPLUG 4
-#define BIO_RW_META 5
-#define BIO_RW_DISCARD 6
-#define BIO_RW_FAILFAST_DEV 7
-#define BIO_RW_FAILFAST_TRANSPORT 8
-#define BIO_RW_FAILFAST_DRIVER 9
-#define BIO_RW_NOIDLE 10
+enum bio_rw_flags {
+ BIO_RW,
+ BIO_RW_FAILFAST_DEV,
+ BIO_RW_FAILFAST_TRANSPORT,
+ BIO_RW_FAILFAST_DRIVER,
+ /* above flags must match REQ_* */
+ BIO_RW_AHEAD,
+ BIO_RW_BARRIER,
+ BIO_RW_SYNCIO,
+ BIO_RW_UNPLUG,
+ BIO_RW_META,
+ BIO_RW_DISCARD,
+ BIO_RW_NOIDLE,
+};
#define bio_rw_flagged(bio, flag) ((bio)->bi_rw & (1 << (flag)))