1 files changed, 22 insertions, 184 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 32e6622767ad..65114e4d9f65 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -149,20 +149,9 @@ struct mapped_device {
         int flush_error;
 
         /*
-         * Protect barrier_error from concurrent endio processing
-         * in request-based dm.
-         */
-        spinlock_t barrier_error_lock;
-        int barrier_error;
-
-        /*
-         * Processing queue (flush/barriers)
+         * Processing queue (flush)
          */
         struct workqueue_struct *wq;
-        struct work_struct barrier_work;
-
-        /* A pointer to the currently processing pre/post flush request */
-        struct request *flush_request;
 
         /*
          * The current mapping.
@@ -750,23 +739,6 @@ static void end_clone_bio(struct bio *clone, int error)
         blk_update_request(tio->orig, 0, nr_bytes);
 }
 
-static void store_barrier_error(struct mapped_device *md, int error)
-{
-        unsigned long flags;
-
-        spin_lock_irqsave(&md->barrier_error_lock, flags);
-        /*
-         * Basically, the first error is taken, but:
-         *   -EOPNOTSUPP supersedes any I/O error.
-         *   Requeue request supersedes any I/O error but -EOPNOTSUPP.
-         */
-        if (!md->barrier_error || error == -EOPNOTSUPP ||
-            (md->barrier_error != -EOPNOTSUPP &&
-             error == DM_ENDIO_REQUEUE))
-                md->barrier_error = error;
-        spin_unlock_irqrestore(&md->barrier_error_lock, flags);
-}
-
 /*
  * Don't touch any member of the md after calling this function because
  * the md may be freed in dm_put() at the end of this function.
@@ -804,13 +776,11 @@ static void free_rq_clone(struct request *clone)
 static void dm_end_request(struct request *clone, int error)
 {
         int rw = rq_data_dir(clone);
-        int run_queue = 1;
-        bool is_barrier = clone->cmd_flags & REQ_HARDBARRIER;
         struct dm_rq_target_io *tio = clone->end_io_data;
         struct mapped_device *md = tio->md;
         struct request *rq = tio->orig;
 
-        if (rq->cmd_type == REQ_TYPE_BLOCK_PC && !is_barrier) {
+        if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
                 rq->errors = clone->errors;
                 rq->resid_len = clone->resid_len;
 
@@ -824,15 +794,8 @@ static void dm_end_request(struct request *clone, int error)
         }
 
         free_rq_clone(clone);
-
-        if (unlikely(is_barrier)) {
-                if (unlikely(error))
-                        store_barrier_error(md, error);
-                run_queue = 0;
-        } else
-                blk_end_request_all(rq, error);
-
-        rq_completed(md, rw, run_queue);
+        blk_end_request_all(rq, error);
+        rq_completed(md, rw, true);
 }
 
 static void dm_unprep_request(struct request *rq)
@@ -857,16 +820,6 @@ void dm_requeue_unmapped_request(struct request *clone)
         struct request_queue *q = rq->q;
         unsigned long flags;
 
-        if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) {
-                /*
-                 * Barrier clones share an original request.
-                 * Leave it to dm_end_request(), which handles this special
-                 * case.
-                 */
-                dm_end_request(clone, DM_ENDIO_REQUEUE);
-                return;
-        }
-
         dm_unprep_request(rq);
 
         spin_lock_irqsave(q->queue_lock, flags);
@@ -956,19 +909,6 @@ static void dm_complete_request(struct request *clone, int error)
         struct dm_rq_target_io *tio = clone->end_io_data;
         struct request *rq = tio->orig;
 
-        if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) {
-                /*
-                 * Barrier clones share an original request.  So can't use
-                 * softirq_done with the original.
-                 * Pass the clone to dm_done() directly in this special case.
-                 * It is safe (even if clone->q->queue_lock is held here)
-                 * because there is no I/O dispatching during the completion
-                 * of barrier clone.
-                 */
-                dm_done(clone, error, true);
-                return;
-        }
-
         tio->error = error;
         rq->completion_data = clone;
         blk_complete_request(rq);
@@ -985,17 +925,6 @@ void dm_kill_unmapped_request(struct request *clone, int error)
         struct dm_rq_target_io *tio = clone->end_io_data;
         struct request *rq = tio->orig;
 
-        if (unlikely(clone->cmd_flags & REQ_HARDBARRIER)) {
-                /*
-                 * Barrier clones share an original request.
-                 * Leave it to dm_end_request(), which handles this special
-                 * case.
-                 */
-                BUG_ON(error > 0);
-                dm_end_request(clone, error);
-                return;
-        }
-
         rq->cmd_flags |= REQ_FAILED;
         dm_complete_request(clone, error);
 }
@@ -1536,14 +1465,6 @@ static int dm_request(struct request_queue *q, struct bio *bio)
         return _dm_request(q, bio);
 }
 
-static bool dm_rq_is_flush_request(struct request *rq)
-{
-        if (rq->cmd_flags & REQ_FLUSH)
-                return true;
-        else
-                return false;
-}
-
 void dm_dispatch_request(struct request *rq)
 {
         int r;
@@ -1591,22 +1512,15 @@ static int setup_clone(struct request *clone, struct request *rq,
 {
         int r;
 
-        if (dm_rq_is_flush_request(rq)) {
-                blk_rq_init(NULL, clone);
-                clone->cmd_type = REQ_TYPE_FS;
-                clone->cmd_flags |= (REQ_HARDBARRIER | WRITE);
-        } else {
-                r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
-                                      dm_rq_bio_constructor, tio);
-                if (r)
-                        return r;
-
-                clone->cmd = rq->cmd;
-                clone->cmd_len = rq->cmd_len;
-                clone->sense = rq->sense;
-                clone->buffer = rq->buffer;
-        }
+        r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
+                              dm_rq_bio_constructor, tio);
+        if (r)
+                return r;
 
+        clone->cmd = rq->cmd;
+        clone->cmd_len = rq->cmd_len;
+        clone->sense = rq->sense;
+        clone->buffer = rq->buffer;
         clone->end_io = end_clone_request;
         clone->end_io_data = tio;
 
@@ -1647,9 +1561,6 @@ static int dm_prep_fn(struct request_queue *q, struct request *rq)
         struct mapped_device *md = q->queuedata;
         struct request *clone;
 
-        if (unlikely(dm_rq_is_flush_request(rq)))
-                return BLKPREP_OK;
-
         if (unlikely(rq->special)) {
                 DMWARN("Already has something in rq->special.");
                 return BLKPREP_KILL;
@@ -1726,6 +1637,7 @@ static void dm_request_fn(struct request_queue *q)
         struct dm_table *map = dm_get_live_table(md);
         struct dm_target *ti;
         struct request *rq, *clone;
+        sector_t pos;
 
         /*
          * For suspend, check blk_queue_stopped() and increment
@@ -1738,15 +1650,14 @@ static void dm_request_fn(struct request_queue *q)
                 if (!rq)
                         goto plug_and_out;
 
-                if (unlikely(dm_rq_is_flush_request(rq))) {
-                        BUG_ON(md->flush_request);
-                        md->flush_request = rq;
-                        blk_start_request(rq);
-                        queue_work(md->wq, &md->barrier_work);
-                        goto out;
-                }
+                /* always use block 0 to find the target for flushes for now */
+                pos = 0;
+                if (!(rq->cmd_flags & REQ_FLUSH))
+                        pos = blk_rq_pos(rq);
+
+                ti = dm_table_find_target(map, pos);
+                BUG_ON(!dm_target_is_valid(ti));
 
-                ti = dm_table_find_target(map, blk_rq_pos(rq));
                 if (ti->type->busy && ti->type->busy(ti))
                         goto plug_and_out;
 
@@ -1917,7 +1828,6 @@ out:
 static const struct block_device_operations dm_blk_dops;
 
 static void dm_wq_work(struct work_struct *work);
-static void dm_rq_barrier_work(struct work_struct *work);
 
 static void dm_init_md_queue(struct mapped_device *md)
 {
@@ -1972,7 +1882,6 @@ static struct mapped_device *alloc_dev(int minor)
         mutex_init(&md->suspend_lock);
         mutex_init(&md->type_lock);
         spin_lock_init(&md->deferred_lock);
-        spin_lock_init(&md->barrier_error_lock);
         rwlock_init(&md->map_lock);
         atomic_set(&md->holders, 1);
         atomic_set(&md->open_count, 0);
@@ -1995,7 +1904,6 @@ static struct mapped_device *alloc_dev(int minor)
         atomic_set(&md->pending[1], 0);
         init_waitqueue_head(&md->wait);
         INIT_WORK(&md->work, dm_wq_work);
-        INIT_WORK(&md->barrier_work, dm_rq_barrier_work);
         init_waitqueue_head(&md->eventq);
 
         md->disk->major = _major;
@@ -2245,8 +2153,6 @@ static int dm_init_request_based_queue(struct mapped_device *md)
         blk_queue_softirq_done(md->queue, dm_softirq_done);
         blk_queue_prep_rq(md->queue, dm_prep_fn);
         blk_queue_lld_busy(md->queue, dm_lld_busy);
-        /* no flush support for request based dm yet */
-        blk_queue_flush(md->queue, 0);
 
         elv_register_queue(md->queue);
 
@@ -2483,73 +2389,6 @@ static void dm_queue_flush(struct mapped_device *md)
         queue_work(md->wq, &md->work);
 }
 
-static void dm_rq_set_target_request_nr(struct request *clone, unsigned request_nr)
-{
-        struct dm_rq_target_io *tio = clone->end_io_data;
-
-        tio->info.target_request_nr = request_nr;
-}
-
-/* Issue barrier requests to targets and wait for their completion. */
-static int dm_rq_barrier(struct mapped_device *md)
-{
-        int i, j;
-        struct dm_table *map = dm_get_live_table(md);
-        unsigned num_targets = dm_table_get_num_targets(map);
-        struct dm_target *ti;
-        struct request *clone;
-
-        md->barrier_error = 0;
-
-        for (i = 0; i < num_targets; i++) {
-                ti = dm_table_get_target(map, i);
-                for (j = 0; j < ti->num_flush_requests; j++) {
-                        clone = clone_rq(md->flush_request, md, GFP_NOIO);
-                        dm_rq_set_target_request_nr(clone, j);
-                        atomic_inc(&md->pending[rq_data_dir(clone)]);
-                        map_request(ti, clone, md);
-                }
-        }
-
-        dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
-        dm_table_put(map);
-
-        return md->barrier_error;
-}
-
-static void dm_rq_barrier_work(struct work_struct *work)
-{
-        int error;
-        struct mapped_device *md = container_of(work, struct mapped_device,
-                                                barrier_work);
-        struct request_queue *q = md->queue;
-        struct request *rq;
-        unsigned long flags;
-
-        /*
-         * Hold the md reference here and leave it at the last part so that
-         * the md can't be deleted by device opener when the barrier request
-         * completes.
-         */
-        dm_get(md);
-
-        error = dm_rq_barrier(md);
-
-        rq = md->flush_request;
-        md->flush_request = NULL;
-
-        if (error == DM_ENDIO_REQUEUE) {
-                spin_lock_irqsave(q->queue_lock, flags);
-                blk_requeue_request(q, rq);
-                spin_unlock_irqrestore(q->queue_lock, flags);
-        } else
-                blk_end_request_all(rq, error);
-
-        blk_run_queue(q);
-
-        dm_put(md);
-}
-
 /*
  * Swap in a new table, returning the old one for the caller to destroy.
  */
@@ -2686,9 +2525,8 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
         up_write(&md->io_lock);
 
         /*
-         * Request-based dm uses md->wq for barrier (dm_rq_barrier_work) which
-         * can be kicked until md->queue is stopped.  So stop md->queue before
-         * flushing md->wq.
+         * Stop md->queue before flushing md->wq in case request-based
+         * dm defers requests to md->wq from md->queue.
          */
         if (dm_request_based(md))
                 stop_queue(md->queue);