md/raid5: call bio_endio() directly rather than queueing for later.

We currently gather bios that need to be returned into a bio_list
and call bio_endio() on them all together.
The original reason for this was to avoid making the calls while
holding a spinlock.
Locking has changed a lot since then, and that reason is no longer
valid.

So discard return_io() and various return_bi lists, and just call
bio_endio() directly as needed.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index f5034ec..5be8dbc 100644 (file)
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -308,8 +308,7 @@ static void __r5l_set_io_unit_state(struct r5l_io_unit *io,
 }
 
 static void
-r5c_return_dev_pending_writes(struct r5conf *conf, struct r5dev *dev,
-                             struct bio_list *return_bi)
+r5c_return_dev_pending_writes(struct r5conf *conf, struct r5dev *dev)
 {
        struct bio *wbi, *wbi2;
 
@@ -319,23 +318,21 @@ r5c_return_dev_pending_writes(struct r5conf *conf, struct r5dev *dev,
               dev->sector + STRIPE_SECTORS) {
                wbi2 = r5_next_bio(wbi, dev->sector);
                md_write_end(conf->mddev);
-               if (!raid5_dec_bi_active_stripes(wbi)) {
-                       bio_list_add(return_bi, wbi);
-               }
+               if (!raid5_dec_bi_active_stripes(wbi))
+                       bio_endio(wbi);
                wbi = wbi2;
        }
 }
 
 void r5c_handle_cached_data_endio(struct r5conf *conf,
-         struct stripe_head *sh, int disks, struct bio_list *return_bi)
+                                 struct stripe_head *sh, int disks)
 {
        int i;
 
        for (i = sh->disks; i--; ) {
                if (sh->dev[i].written) {
                        set_bit(R5_UPTODATE, &sh->dev[i].flags);
-                       r5c_return_dev_pending_writes(conf, &sh->dev[i],
-                                                     return_bi);
+                       r5c_return_dev_pending_writes(conf, &sh->dev[i]);
                        bitmap_endwrite(conf->mddev->bitmap, sh->sector,
                                        STRIPE_SECTORS,
                                        !test_bit(STRIPE_DEGRADED, &sh->state),

diff --git a/drivers/md/raid5-log.h b/drivers/md/raid5-log.h
index 4f5a0f4..738930f 100644 (file)
--- a/drivers/md/raid5-log.h
+++ b/drivers/md/raid5-log.h
@@ -21,7 +21,7 @@ extern void r5c_release_extra_page(struct stripe_head *sh);
 extern void r5c_use_extra_page(struct stripe_head *sh);
 extern void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
 extern void r5c_handle_cached_data_endio(struct r5conf *conf,
-       struct stripe_head *sh, int disks, struct bio_list *return_bi);
+       struct stripe_head *sh, int disks);
 extern int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh);
 extern void r5c_make_stripe_write_out(struct stripe_head *sh);
 extern void r5c_flush_cache(struct r5conf *conf, int num);

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a2c9ddc..44c8ceb 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -158,17 +158,6 @@ static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
        return slot;
 }
 
-static void return_io(struct bio_list *return_bi)
-{
-       struct bio *bi;
-       while ((bi = bio_list_pop(return_bi)) != NULL) {
-               bi->bi_iter.bi_size = 0;
-               trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
-                                        bi, 0);
-               bio_endio(bi);
-       }
-}
-
 static void print_raid5_conf (struct r5conf *conf);
 
 static int stripe_operations_active(struct stripe_head *sh)
@@ -1310,7 +1299,6 @@ async_copy_data(int frombio, struct bio *bio, struct page **page,
 static void ops_complete_biofill(void *stripe_head_ref)
 {
        struct stripe_head *sh = stripe_head_ref;
-       struct bio_list return_bi = BIO_EMPTY_LIST;
        int i;
 
        pr_debug("%s: stripe %llu\n", __func__,
@@ -1335,15 +1323,13 @@ static void ops_complete_biofill(void *stripe_head_ref)
                                dev->sector + STRIPE_SECTORS) {
                                rbi2 = r5_next_bio(rbi, dev->sector);
                                if (!raid5_dec_bi_active_stripes(rbi))
-                                       bio_list_add(&return_bi, rbi);
+                                       bio_endio(rbi);
                                rbi = rbi2;
                        }
                }
        }
        clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
 
-       return_io(&return_bi);
-
        set_bit(STRIPE_HANDLE, &sh->state);
        raid5_release_stripe(sh);
 }
@@ -3351,8 +3337,7 @@ static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 
 static void
 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
-                               struct stripe_head_state *s, int disks,
-                               struct bio_list *return_bi)
+                    struct stripe_head_state *s, int disks)
 {
        int i;
        BUG_ON(sh->batch_head);
@@ -3400,7 +3385,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                        bi->bi_error = -EIO;
                        md_write_end(conf->mddev);
                        if (!raid5_dec_bi_active_stripes(bi))
-                               bio_list_add(return_bi, bi);
+                               bio_endio(bi);
                        bi = nextbi;
                }
                if (bitmap_end)
@@ -3423,7 +3408,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                        bi->bi_error = -EIO;
                        md_write_end(conf->mddev);
                        if (!raid5_dec_bi_active_stripes(bi))
-                               bio_list_add(return_bi, bi);
+                               bio_endio(bi);
                        bi = bi2;
                }
 
@@ -3449,7 +3434,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
 
                                bi->bi_error = -EIO;
                                if (!raid5_dec_bi_active_stripes(bi))
-                                       bio_list_add(return_bi, bi);
+                                       bio_endio(bi);
                                bi = nextbi;
                        }
                }
@@ -3748,7 +3733,7 @@ static void break_stripe_batch_list(struct stripe_head *head_sh,
  * never LOCKED, so we don't need to test 'failed' directly.
  */
 static void handle_stripe_clean_event(struct r5conf *conf,
-       struct stripe_head *sh, int disks, struct bio_list *return_bi)
+       struct stripe_head *sh, int disks)
 {
        int i;
        struct r5dev *dev;
@@ -3782,7 +3767,7 @@ returnbi:
                                        wbi2 = r5_next_bio(wbi, dev->sector);
                                        md_write_end(conf->mddev);
                                        if (!raid5_dec_bi_active_stripes(wbi))
-                                               bio_list_add(return_bi, wbi);
+                                               bio_endio(wbi);
                                        wbi = wbi2;
                                }
                                bitmap_endwrite(conf->mddev->bitmap, sh->sector,
@@ -4725,7 +4710,7 @@ static void handle_stripe(struct stripe_head *sh)
                sh->reconstruct_state = 0;
                break_stripe_batch_list(sh, 0);
                if (s.to_read+s.to_write+s.written)
-                       handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);
+                       handle_failed_stripe(conf, sh, &s, disks);
                if (s.syncing + s.replacing)
                        handle_failed_sync(conf, sh, &s);
        }
@@ -4791,10 +4776,10 @@ static void handle_stripe(struct stripe_head *sh)
                             && !test_bit(R5_LOCKED, &qdev->flags)
                             && (test_bit(R5_UPTODATE, &qdev->flags) ||
                                 test_bit(R5_Discard, &qdev->flags))))))
-               handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
+               handle_stripe_clean_event(conf, sh, disks);
 
        if (s.just_cached)
-               r5c_handle_cached_data_endio(conf, sh, disks, &s.return_bi);
+               r5c_handle_cached_data_endio(conf, sh, disks);
        log_stripe_write_finished(sh);
 
        /* Now we might consider reading some blocks, either to check/generate
@@ -5022,9 +5007,6 @@ finish:
                        md_wakeup_thread(conf->mddev->thread);
        }
 
-       if (!bio_list_empty(&s.return_bi))
-               return_io(&s.return_bi);
-
        clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
 }
 

diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 13800dc..fd5c21c 100644 (file)
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -278,7 +278,6 @@ struct stripe_head_state {
        int dec_preread_active;
        unsigned long ops_request;
 
-       struct bio_list return_bi;
        struct md_rdev *blocked_rdev;
        int handle_bad_blocks;
        int log_failed;