block: Add and use op_stat_group() for indexing disk_stat fields.

Add and use a new op_stat_group() function for indexing partition stat
fields rather than indexing them by rq_data_dir() or bio_data_dir().
This function works similarly to op_is_sync() in that it takes the
request::cmd_flags or bio::bi_opf flags and determines which stats
should et updated.

In addition, the second parameter to generic_start_io_acct() and
generic_end_io_acct() is now a REQ_OP rather than simply a read or
write bit and it uses op_stat_group() on the parameter to determine
the stat group.

Note that the partition in_flight counts are not part of the per-cpu
statistics and as such are not indexed via this function.  It's now
indexed by op_is_write().

tj: Refreshed on top of v4.17.  Updated to pass around REQ_OP.

Signed-off-by: Michael Callahan <michaelcallahan@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Matias Bjorling <mb@lightnvm.io>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

2 files changed, 6 insertions, 4 deletions

diff --git a/drivers/lightnvm/pblk-cache.c b/drivers/lightnvm/pblk-cache.c
index 77d811962818..f565a56b898a 100644
--- a/drivers/lightnvm/pblk-cache.c
+++ b/drivers/lightnvm/pblk-cache.c
@@ -27,7 +27,8 @@ int pblk_write_to_cache(struct pblk *pblk, struct bio *bio, unsigned long flags)
         int nr_entries = pblk_get_secs(bio);
         int i, ret;
 
-        generic_start_io_acct(q, WRITE, bio_sectors(bio), &pblk->disk->part0);
+        generic_start_io_acct(q, REQ_OP_WRITE, bio_sectors(bio),
+                              &pblk->disk->part0);
 
         /* Update the write buffer head (mem) with the entries that we can
          * write. The write in itself cannot fail, so there is no need to
@@ -75,7 +76,7 @@ retry:
         pblk_rl_inserted(&pblk->rl, nr_entries);
 
 out:
-        generic_end_io_acct(q, WRITE, &pblk->disk->part0, start_time);
+        generic_end_io_acct(q, REQ_OP_WRITE, &pblk->disk->part0, start_time);
         pblk_write_should_kick(pblk);
         return ret;
 }
diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
index 26d414ae25b6..5a46d7f9302f 100644
--- a/drivers/lightnvm/pblk-read.c
+++ b/drivers/lightnvm/pblk-read.c
@@ -199,7 +199,7 @@ static void __pblk_end_io_read(struct pblk *pblk, struct nvm_rq *rqd,
         struct bio *int_bio = rqd->bio;
         unsigned long start_time = r_ctx->start_time;
 
-        generic_end_io_acct(dev->q, READ, &pblk->disk->part0, start_time);
+        generic_end_io_acct(dev->q, REQ_OP_READ, &pblk->disk->part0, start_time);
 
         if (rqd->error)
                 pblk_log_read_err(pblk, rqd);
@@ -461,7 +461,8 @@ int pblk_submit_read(struct pblk *pblk, struct bio *bio)
                 return NVM_IO_ERR;
         }
 
-        generic_start_io_acct(q, READ, bio_sectors(bio), &pblk->disk->part0);
+        generic_start_io_acct(q, REQ_OP_READ, bio_sectors(bio),
+                              &pblk->disk->part0);
 
         bitmap_zero(read_bitmap, nr_secs);