md/raid1: submit IO from originating thread instead of md thread.

queuing writes to the md thread means that all requests go through the
one processor which may not be able to keep up with very high request
rates.

So use the plugging infrastructure to submit all requests on unplug.
If a 'schedule' is needed, we fall back on the old approach of handing
the requests to the thread for it to handle.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 15dbe03117e4..94e7f6ba2e11 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1305,7 +1305,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
                                         TASK_UNINTERRUPTIBLE);
                         spin_unlock_irq(&bitmap->counts.lock);
-                        io_schedule();
+                        schedule();
                         finish_wait(&bitmap->overflow_wait, &__wait);
                         continue;
                 }