The top bits of bio->bi_flags are reserved for keeping the
allocation pool, set aside the next 16 bits for carrying
a stream ID. That leaves us with support for 64k - 1 streams,
0 is reserved as a "stream not set" value.
Add helpers for setting/getting stream ID of a bio.
Signed-off-by: Jens Axboe <axboe@xxxxxx>
---
block/bio.c | 5 ++++
block/blk-core.c | 4 ++++
include/linux/blk_types.h | 60 ++++++++++++++++++++++++++++++++++-------------
3 files changed, 53 insertions(+), 16 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index cf7591551b17..d42e69c23271 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -584,6 +584,7 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
bio->bi_rw = bio_src->bi_rw;
bio->bi_iter = bio_src->bi_iter;
bio->bi_io_vec = bio_src->bi_io_vec;
+ bio_set_streamid(bio, bio_get_streamid(bio_src));
}
EXPORT_SYMBOL(__bio_clone_fast);
@@ -689,6 +690,7 @@ integrity_clone:
}
}
+ bio_set_streamid(bio, bio_get_streamid(bio_src));
return bio;
}
EXPORT_SYMBOL(bio_clone_bioset);
@@ -2037,6 +2039,9 @@ static void __init biovec_init_slabs(void)
static int __init init_bio(void)
{
+ BUILD_BUG_ON(BIO_FLAG_LAST > ((8 * sizeof(unsigned int)) -
+ BIO_POOL_BITS - BIO_STREAM_BITS));
+
bio_slab_max = 2;
bio_slab_nr = 0;
bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
diff --git a/block/blk-core.c b/block/blk-core.c
index b83d29755b5a..e4b12693c567 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2071,6 +2071,10 @@ blk_qc_t generic_make_request(struct bio *bio)
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
if (likely(blk_queue_enter(q, false) == 0)) {
+ if (bio_streamid_valid(bio))
+ blk_add_trace_msg(q, "StreamID=%u",
+ bio_get_streamid(bio));
+
ret = q->make_request_fn(q, bio);
blk_queue_exit(q);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 86a38ea1823f..fc63a82a9944 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -112,21 +112,23 @@ struct bio {
/*
* bio flags
*/
-#define BIO_SEG_VALID 1 /* bi_phys_segments valid */
-#define BIO_CLONED 2 /* doesn't own data */
-#define BIO_BOUNCED 3 /* bio is a bounce bio */
-#define BIO_USER_MAPPED 4 /* contains user pages */
-#define BIO_NULL_MAPPED 5 /* contains invalid user pages */
-#define BIO_QUIET 6 /* Make BIO Quiet */
-#define BIO_CHAIN 7 /* chained bio, ->bi_remaining in effect */
-#define BIO_REFFED 8 /* bio has elevated ->bi_cnt */
-
-/*
- * Flags starting here get preserved by bio_reset() - this includes
- * BIO_POOL_IDX()
- */
-#define BIO_RESET_BITS 13
-#define BIO_OWNS_VEC 13 /* bio_free() should free bvec */
+enum {
+ BIO_SEG_VALID = 0, /* bi_phys_segments valid */
+ BIO_CLONED, /* doesn't own data */
+ BIO_BOUNCED, /* bio is a bounce bio */
+ BIO_USER_MAPPED, /* contains user pages */
+ BIO_NULL_MAPPED, /* contains invalid user pages */
+ BIO_QUIET, /* Mnake BIO Quiet */
+ BIO_CHAIN, /* chained bio, ->bi_remaining in effect */
+ BIO_REFFED, /* bio has elevated ->bi_cnt */
+ BIO_OWNS_VEC, /* bio_free() should free bvec */
+ BIO_FLAG_LAST, /* end of bits */
+ /*
+ * Flags starting here get preserved by bio_reset() - this includes
+ * BIO_POOL_IDX()
+ */
+ BIO_RESET_BITS = BIO_FLAG_LAST,
+};
/*
* top 4 bits of bio flags indicate the pool this bio came from
@@ -134,9 +136,35 @@ struct bio {
#define BIO_POOL_BITS (4)
#define BIO_POOL_NONE ((1UL << BIO_POOL_BITS) - 1)
#define BIO_POOL_OFFSET (32 - BIO_POOL_BITS)
-#define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET)
#define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET)
+/*
+ * after the pool bits, next 16 bits are for the stream id
+ */
+#define BIO_STREAM_BITS (16)
+#define BIO_STREAM_OFFSET (BIO_POOL_OFFSET - BIO_STREAM_BITS)
+#define BIO_STREAM_MASK ((1 << BIO_STREAM_BITS) - 1)
+
+static inline unsigned long streamid_to_flags(unsigned int id)
+{
+ return (unsigned long) (id & BIO_STREAM_MASK) << BIO_STREAM_OFFSET;
+}
+
+static inline void bio_set_streamid(struct bio *bio, unsigned int id)
+{
+ bio->bi_flags |= streamid_to_flags(id);
+}
+
+static inline unsigned int bio_get_streamid(struct bio *bio)
+{
+ return (bio->bi_flags >> BIO_STREAM_OFFSET) & BIO_STREAM_MASK;
+}
+
+static inline bool bio_streamid_valid(struct bio *bio)
+{
+ return bio_get_streamid(bio) != 0;
+}
+
#endif /* CONFIG_BLOCK */
/*
--
2.4.1.168.g1ea28e1
--
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