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-rw-r--r--include/linux/bio.h33
1 files changed, 24 insertions, 9 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h
index ff5b4cf9e2d..1c91a176b9a 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -79,6 +79,13 @@ struct bio {
unsigned int bi_size; /* residual I/O count */
+ /*
+ * To keep track of the max segment size, we account for the
+ * sizes of the first and last mergeable segments in this bio.
+ */
+ unsigned int bi_seg_front_size;
+ unsigned int bi_seg_back_size;
+
unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
unsigned int bi_comp_cpu; /* completion CPU */
@@ -129,25 +136,30 @@ struct bio {
* bit 2 -- barrier
* Insert a serialization point in the IO queue, forcing previously
* submitted IO to be completed before this oen is issued.
- * bit 3 -- fail fast, don't want low level driver retries
- * bit 4 -- synchronous I/O hint: the block layer will unplug immediately
+ * bit 3 -- synchronous I/O hint: the block layer will unplug immediately
* Note that this does NOT indicate that the IO itself is sync, just
* that the block layer will not postpone issue of this IO by plugging.
- * bit 5 -- metadata request
+ * bit 4 -- 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 5 -- 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 6 -- fail fast device errors
+ * bit 7 -- fail fast transport errors
+ * bit 8 -- fail fast driver errors
+ * Don't want driver retries for any fast fail whatever the reason.
*/
#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_FAILFAST 3
-#define BIO_RW_SYNC 4
-#define BIO_RW_META 5
-#define BIO_RW_DISCARD 6
+#define BIO_RW_SYNC 3
+#define BIO_RW_META 4
+#define BIO_RW_DISCARD 5
+#define BIO_RW_FAILFAST_DEV 6
+#define BIO_RW_FAILFAST_TRANSPORT 7
+#define BIO_RW_FAILFAST_DRIVER 8
/*
* upper 16 bits of bi_rw define the io priority of this bio
@@ -174,7 +186,10 @@ struct bio {
#define bio_sectors(bio) ((bio)->bi_size >> 9)
#define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER))
#define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC))
-#define bio_failfast(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
+#define bio_failfast_dev(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST_DEV))
+#define bio_failfast_transport(bio) \
+ ((bio)->bi_rw & (1 << BIO_RW_FAILFAST_TRANSPORT))
+#define bio_failfast_driver(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST_DRIVER))
#define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
#define bio_rw_meta(bio) ((bio)->bi_rw & (1 << BIO_RW_META))
#define bio_discard(bio) ((bio)->bi_rw & (1 << BIO_RW_DISCARD))