md/raid5: add blktrace calls

This makes it easier to trace what raid5 is doing.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 35 insertions, 3 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 2cf23f23ddc..ffebc1e8f48 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -53,6 +53,8 @@
 #include <linux/cpu.h>
 #include <linux/slab.h>
 #include <linux/ratelimit.h>
+#include <trace/events/block.h>
+
 #include "md.h"
 #include "raid5.h"
 #include "raid0.h"
@@ -182,6 +184,8 @@ static void return_io(struct bio *return_bi)
                 return_bi = bi->bi_next;
                 bi->bi_next = NULL;
                 bi->bi_size = 0;
+                trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
+                                         bi, 0);
                 bio_endio(bi, 0);
                 bi = return_bi;
         }
@@ -671,6 +675,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
                         bi->bi_next = NULL;
                         if (rrdev)
                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
+                        trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
+                                              bi, disk_devt(conf->mddev->gendisk),
+                                              sh->dev[i].sector);
                         generic_make_request(bi);
                 }
                 if (rrdev) {
@@ -698,6 +705,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
                         rbi->bi_io_vec[0].bv_offset = 0;
                         rbi->bi_size = STRIPE_SIZE;
                         rbi->bi_next = NULL;
+                        trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
+                                              rbi, disk_devt(conf->mddev->gendisk),
+                                              sh->dev[i].sector);
                         generic_make_request(rbi);
                 }
                 if (!rdev && !rrdev) {
@@ -2855,8 +2865,10 @@ static void handle_stripe_dirtying(struct r5conf *conf,
         pr_debug("for sector %llu, rmw=%d rcw=%d\n",
                 (unsigned long long)sh->sector, rmw, rcw);
         set_bit(STRIPE_HANDLE, &sh->state);
-        if (rmw < rcw && rmw > 0)
+        if (rmw < rcw && rmw > 0) {
                 /* prefer read-modify-write, but need to get some data */
+                blk_add_trace_msg(conf->mddev->queue, "raid5 rmw %llu %d",
+                                  (unsigned long long)sh->sector, rmw);
                 for (i = disks; i--; ) {
                         struct r5dev *dev = &sh->dev[i];
                         if ((dev->towrite || i == sh->pd_idx) &&
@@ -2867,7 +2879,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
                                 if (
                                   test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
                                         pr_debug("Read_old block "
-                                                "%d for r-m-w\n", i);
+                                                 "%d for r-m-w\n", i);
                                         set_bit(R5_LOCKED, &dev->flags);
                                         set_bit(R5_Wantread, &dev->flags);
                                         s->locked++;
@@ -2877,8 +2889,10 @@ static void handle_stripe_dirtying(struct r5conf *conf,
                                 }
                         }
                 }
+        }
         if (rcw <= rmw && rcw > 0) {
                 /* want reconstruct write, but need to get some data */
+                int qread =0;
                 rcw = 0;
                 for (i = disks; i--; ) {
                         struct r5dev *dev = &sh->dev[i];
@@ -2897,12 +2911,17 @@ static void handle_stripe_dirtying(struct r5conf *conf,
                                         set_bit(R5_LOCKED, &dev->flags);
                                         set_bit(R5_Wantread, &dev->flags);
                                         s->locked++;
+                                        qread++;
                                 } else {
                                         set_bit(STRIPE_DELAYED, &sh->state);
                                         set_bit(STRIPE_HANDLE, &sh->state);
                                 }
                         }
                 }
+                if (rcw)
+                        blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
+                                          (unsigned long long)sh->sector,
+                                          rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
         }
         /* now if nothing is locked, and if we have enough data,
          * we can start a write request
@@ -3900,6 +3919,8 @@ static void raid5_align_endio(struct bio *bi, int error)
         rdev_dec_pending(rdev, conf->mddev);
 
         if (!error && uptodate) {
+                trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
+                                         raid_bi, 0);
                 bio_endio(raid_bi, 0);
                 if (atomic_dec_and_test(&conf->active_aligned_reads))
                         wake_up(&conf->wait_for_stripe);
@@ -4004,6 +4025,9 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
                 atomic_inc(&conf->active_aligned_reads);
                 spin_unlock_irq(&conf->device_lock);
 
+                trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
+                                      align_bi, disk_devt(mddev->gendisk),
+                                      raid_bio->bi_sector);
                 generic_make_request(align_bi);
                 return 1;
         } else {
@@ -4078,6 +4102,7 @@ static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
         struct stripe_head *sh;
         struct mddev *mddev = cb->cb.data;
         struct r5conf *conf = mddev->private;
+        int cnt = 0;
 
         if (cb->list.next && !list_empty(&cb->list)) {
                 spin_lock_irq(&conf->device_lock);
@@ -4092,9 +4117,11 @@ static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
                         smp_mb__before_clear_bit();
                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
                         __release_stripe(conf, sh);
+                        cnt++;
                 }
                 spin_unlock_irq(&conf->device_lock);
         }
+        trace_block_unplug(mddev->queue, cnt, !from_schedule);
         kfree(cb);
 }
 
@@ -4352,6 +4379,8 @@ static void make_request(struct mddev *mddev, struct bio * bi)
                 if ( rw == WRITE )
                         md_write_end(mddev);
 
+                trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
+                                         bi, 0);
                 bio_endio(bi, 0);
         }
 }
@@ -4728,8 +4757,11 @@ static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
                 handled++;
         }
         remaining = raid5_dec_bi_active_stripes(raid_bio);
-        if (remaining == 0)
+        if (remaining == 0) {
+                trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
+                                         raid_bio, 0);
                 bio_endio(raid_bio, 0);
+        }
         if (atomic_dec_and_test(&conf->active_aligned_reads))
                 wake_up(&conf->wait_for_stripe);
         return handled;