block: get rid of struct blk_issue_stat

struct blk_issue_stat squashes three things into one u64:

- The time the driver started working on a request
- The original size of the request (for the io.low controller)
- Flags for writeback throttling

It turns out that on x86_64, we have a 4 byte hole in struct request
which we can fill with the non-timestamp fields from blk_issue_stat,
simplifying things quite a bit.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 3 insertions, 3 deletions

diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index 0d6d25e32e1f..564967fafe5f 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -485,11 +485,11 @@ static void kyber_completed_request(struct request *rq)
         if (blk_stat_is_active(kqd->cb))
                 return;
 
-        now = __blk_stat_time(ktime_to_ns(ktime_get()));
-        if (now < blk_stat_time(&rq->issue_stat))
+        now = ktime_get_ns();
+        if (now < rq->io_start_time_ns)
                 return;
 
-        latency = now - blk_stat_time(&rq->issue_stat);
+        latency = now - rq->io_start_time_ns;
 
         if (latency > target)
                 blk_stat_activate_msecs(kqd->cb, 10);