Merge branch 'for-linus' of git://git.kernel.dk/linux-block

Says Jens:

 "Time to push off some of the pending items.  I really wanted to wait
  until we had the regression nailed, but alas it's not quite there yet.
  But I'm very confident that it's "just" a missing expire on exit, so
  fix from Tejun should be fairly trivial.  I'm headed out for a week on
  the slopes.

  - Killing the barrier part of mtip32xx.  It doesn't really support
    barriers, and it doesn't need them (writes are fully ordered).

  - A few fixes from Dan Carpenter, preventing overflows of integer
    multiplication.

  - A fixup for loop, fixing a previous commit that didn't quite solve
    the partial read problem from Dave Young.

  - A bio integer overflow fix from Kent Overstreet.

  - Improvement/fix of the door "keep locked" part of the cdrom shared
    code from Paolo Benzini.

  - A few cfq fixes from Shaohua Li.

  - A fix for bsg sysfs warning when removing a file it did not create
    from Stanislaw Gruszka.

  - Two fixes for floppy from Vivek, preventing a crash.

  - A few block core fixes from Tejun.  One killing the over-optimized
    ioc exit path, cleaning that up nicely.  Two others fixing an oops
    on elevator switch, due to calling into the scheduler merge check
    code without holding the queue lock."

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix lockdep warning on io_context release put_io_context()
  relay: prevent integer overflow in relay_open()
  loop: zero fill bio instead of return -EIO for partial read
  bio: don't overflow in bio_get_nr_vecs()
  floppy: Fix a crash during rmmod
  floppy: Cleanup disk->queue before caling put_disk() if add_disk() was never called
  cdrom: move shared static to cdrom_device_info
  bsg: fix sysfs link remove warning
  block: don't call elevator callbacks for plug merges
  block: separate out blk_rq_merge_ok() and blk_try_merge() from elevator functions
  mtip32xx: removed the irrelevant argument of mtip_hw_submit_io() and the unused member of struct driver_data
  block: strip out locking optimization in put_io_context()
  cdrom: use copy_to_user() without the underscores
  block: fix ioc locking warning
  block: fix NULL icq_cache reference
  block,cfq: change code order

21 files changed, 155 insertions, 233 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index fa8f26309444..75642a352a8f 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1659,7 +1659,7 @@ static void blkiocg_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
 		ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
 		if (ioc) {
 			ioc_cgroup_changed(ioc);
-			put_io_context(ioc, NULL);
+			put_io_context(ioc);
 		}
 	}
 }
diff --git a/block/blk-core.c b/block/blk-core.c
index e6c05a97ee2b..3a78b00edd71 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -642,7 +642,7 @@ static inline void blk_free_request(struct request_queue *q, struct request *rq)
 	if (rq->cmd_flags & REQ_ELVPRIV) {
 		elv_put_request(q, rq);
 		if (rq->elv.icq)
-			put_io_context(rq->elv.icq->ioc, q);
+			put_io_context(rq->elv.icq->ioc);
 	}
 
 	mempool_free(rq, q->rq.rq_pool);
@@ -872,13 +872,15 @@ retry:
 	spin_unlock_irq(q->queue_lock);
 
 	/* create icq if missing */
-	if (unlikely(et->icq_cache && !icq))
+	if ((rw_flags & REQ_ELVPRIV) && unlikely(et->icq_cache && !icq)) {
 		icq = ioc_create_icq(q, gfp_mask);
+		if (!icq)
+			goto fail_icq;
+	}
 
-	/* rqs are guaranteed to have icq on elv_set_request() if requested */
-	if (likely(!et->icq_cache || icq))
-		rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
+	rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
 
+fail_icq:
 	if (unlikely(!rq)) {
 		/*
 		 * Allocation failed presumably due to memory. Undo anything
@@ -1210,7 +1212,6 @@ static bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
 	req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
 
 	drive_stat_acct(req, 0);
-	elv_bio_merged(q, req, bio);
 	return true;
 }
 
@@ -1241,7 +1242,6 @@ static bool bio_attempt_front_merge(struct request_queue *q,
 	req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
 
 	drive_stat_acct(req, 0);
-	elv_bio_merged(q, req, bio);
 	return true;
 }
 
@@ -1255,13 +1255,12 @@ static bool bio_attempt_front_merge(struct request_queue *q,
  * on %current's plugged list.  Returns %true if merge was successful,
  * otherwise %false.
  *
- * This function is called without @q->queue_lock; however, elevator is
- * accessed iff there already are requests on the plugged list which in
- * turn guarantees validity of the elevator.
- *
- * Note that, on successful merge, elevator operation
- * elevator_bio_merged_fn() will be called without queue lock.  Elevator
- * must be ready for this.
+ * Plugging coalesces IOs from the same issuer for the same purpose without
+ * going through @q->queue_lock.  As such it's more of an issuing mechanism
+ * than scheduling, and the request, while may have elvpriv data, is not
+ * added on the elevator at this point.  In addition, we don't have
+ * reliable access to the elevator outside queue lock.  Only check basic
+ * merging parameters without querying the elevator.
  */
 static bool attempt_plug_merge(struct request_queue *q, struct bio *bio,
 			       unsigned int *request_count)
@@ -1280,10 +1279,10 @@ static bool attempt_plug_merge(struct request_queue *q, struct bio *bio,
 
 		(*request_count)++;
 
-		if (rq->q != q)
+		if (rq->q != q || !blk_rq_merge_ok(rq, bio))
 			continue;
 
-		el_ret = elv_try_merge(rq, bio);
+		el_ret = blk_try_merge(rq, bio);
 		if (el_ret == ELEVATOR_BACK_MERGE) {
 			ret = bio_attempt_back_merge(q, rq, bio);
 			if (ret)
@@ -1345,12 +1344,14 @@ void blk_queue_bio(struct request_queue *q, struct bio *bio)
 	el_ret = elv_merge(q, &req, bio);
 	if (el_ret == ELEVATOR_BACK_MERGE) {
 		if (bio_attempt_back_merge(q, req, bio)) {
+			elv_bio_merged(q, req, bio);
 			if (!attempt_back_merge(q, req))
 				elv_merged_request(q, req, el_ret);
 			goto out_unlock;
 		}
 	} else if (el_ret == ELEVATOR_FRONT_MERGE) {
 		if (bio_attempt_front_merge(q, req, bio)) {
+			elv_bio_merged(q, req, bio);
 			if (!attempt_front_merge(q, req))
 				elv_merged_request(q, req, el_ret);
 			goto out_unlock;
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 27a06e00eaec..8b782a63c297 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -29,21 +29,6 @@ void get_io_context(struct io_context *ioc)
 }
 EXPORT_SYMBOL(get_io_context);
 
-/*
- * Releasing ioc may nest into another put_io_context() leading to nested
- * fast path release.  As the ioc's can't be the same, this is okay but
- * makes lockdep whine.  Keep track of nesting and use it as subclass.
- */
-#ifdef CONFIG_LOCKDEP
-#define ioc_release_depth(q)		((q) ? (q)->ioc_release_depth : 0)
-#define ioc_release_depth_inc(q)	(q)->ioc_release_depth++
-#define ioc_release_depth_dec(q)	(q)->ioc_release_depth--
-#else
-#define ioc_release_depth(q)		0
-#define ioc_release_depth_inc(q)	do { } while (0)
-#define ioc_release_depth_dec(q)	do { } while (0)
-#endif
-
 static void icq_free_icq_rcu(struct rcu_head *head)
 {
 	struct io_cq *icq = container_of(head, struct io_cq, __rcu_head);
@@ -75,11 +60,8 @@ static void ioc_exit_icq(struct io_cq *icq)
 	if (rcu_dereference_raw(ioc->icq_hint) == icq)
 		rcu_assign_pointer(ioc->icq_hint, NULL);
 
-	if (et->ops.elevator_exit_icq_fn) {
-		ioc_release_depth_inc(q);
+	if (et->ops.elevator_exit_icq_fn)
 		et->ops.elevator_exit_icq_fn(icq);
-		ioc_release_depth_dec(q);
-	}
 
 	/*
 	 * @icq->q might have gone away by the time RCU callback runs
@@ -98,8 +80,15 @@ static void ioc_release_fn(struct work_struct *work)
 	struct io_context *ioc = container_of(work, struct io_context,
 					      release_work);
 	struct request_queue *last_q = NULL;
+	unsigned long flags;
 
-	spin_lock_irq(&ioc->lock);
+	/*
+	 * Exiting icq may call into put_io_context() through elevator
+	 * which will trigger lockdep warning.  The ioc's are guaranteed to
+	 * be different, use a different locking subclass here.  Use
+	 * irqsave variant as there's no spin_lock_irq_nested().
+	 */
+	spin_lock_irqsave_nested(&ioc->lock, flags, 1);
 
 	while (!hlist_empty(&ioc->icq_list)) {
 		struct io_cq *icq = hlist_entry(ioc->icq_list.first,
@@ -121,15 +110,15 @@ static void ioc_release_fn(struct work_struct *work)
 			 */
 			if (last_q) {
 				spin_unlock(last_q->queue_lock);
-				spin_unlock_irq(&ioc->lock);
+				spin_unlock_irqrestore(&ioc->lock, flags);
 				blk_put_queue(last_q);
 			} else {
-				spin_unlock_irq(&ioc->lock);
+				spin_unlock_irqrestore(&ioc->lock, flags);
 			}
 
 			last_q = this_q;
-			spin_lock_irq(this_q->queue_lock);
-			spin_lock(&ioc->lock);
+			spin_lock_irqsave(this_q->queue_lock, flags);
+			spin_lock_nested(&ioc->lock, 1);
 			continue;
 		}
 		ioc_exit_icq(icq);
@@ -137,10 +126,10 @@ static void ioc_release_fn(struct work_struct *work)
 
 	if (last_q) {
 		spin_unlock(last_q->queue_lock);
-		spin_unlock_irq(&ioc->lock);
+		spin_unlock_irqrestore(&ioc->lock, flags);
 		blk_put_queue(last_q);
 	} else {
-		spin_unlock_irq(&ioc->lock);
+		spin_unlock_irqrestore(&ioc->lock, flags);
 	}
 
 	kmem_cache_free(iocontext_cachep, ioc);
@@ -149,79 +138,29 @@ static void ioc_release_fn(struct work_struct *work)
 /**
  * put_io_context - put a reference of io_context
  * @ioc: io_context to put
- * @locked_q: request_queue the caller is holding queue_lock of (hint)
  *
  * Decrement reference count of @ioc and release it if the count reaches
- * zero.  If the caller is holding queue_lock of a queue, it can indicate
- * that with @locked_q.  This is an optimization hint and the caller is
- * allowed to pass in %NULL even when it's holding a queue_lock.
+ * zero.
  */
-void put_io_context(struct io_context *ioc, struct request_queue *locked_q)
+void put_io_context(struct io_context *ioc)
 {
-	struct request_queue *last_q = locked_q;
 	unsigned long flags;
 
 	if (ioc == NULL)
 		return;
 
 	BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
-	if (locked_q)
-		lockdep_assert_held(locked_q->queue_lock);
-
-	if (!atomic_long_dec_and_test(&ioc->refcount))
-		return;
 
 	/*
-	 * Destroy @ioc.  This is a bit messy because icq's are chained
-	 * from both ioc and queue, and ioc->lock nests inside queue_lock.
-	 * The inner ioc->lock should be held to walk our icq_list and then
-	 * for each icq the outer matching queue_lock should be grabbed.
-	 * ie. We need to do reverse-order double lock dancing.
-	 *
-	 * Another twist is that we are often called with one of the
-	 * matching queue_locks held as indicated by @locked_q, which
-	 * prevents performing double-lock dance for other queues.
-	 *
-	 * So, we do it in two stages.  The fast path uses the queue_lock
-	 * the caller is holding and, if other queues need to be accessed,
-	 * uses trylock to avoid introducing locking dependency.  This can
-	 * handle most cases, especially if @ioc was performing IO on only
-	 * single device.
-	 *
-	 * If trylock doesn't cut it, we defer to @ioc->release_work which
-	 * can do all the double-locking dancing.
+	 * Releasing ioc requires reverse order double locking and we may
+	 * already be holding a queue_lock.  Do it asynchronously from wq.
 	 */
-	spin_lock_irqsave_nested(&ioc->lock, flags,
-				 ioc_release_depth(locked_q));
-
-	while (!hlist_empty(&ioc->icq_list)) {
-		struct io_cq *icq = hlist_entry(ioc->icq_list.first,
-						struct io_cq, ioc_node);
-		struct request_queue *this_q = icq->q;
-
-		if (this_q != last_q) {
-			if (last_q && last_q != locked_q)
-				spin_unlock(last_q->queue_lock);
-			last_q = NULL;
-
-			if (!spin_trylock(this_q->queue_lock))
-				break;
-			last_q = this_q;
-			continue;
-		}
-		ioc_exit_icq(icq);
+	if (atomic_long_dec_and_test(&ioc->refcount)) {
+		spin_lock_irqsave(&ioc->lock, flags);
+		if (!hlist_empty(&ioc->icq_list))
+			schedule_work(&ioc->release_work);
+		spin_unlock_irqrestore(&ioc->lock, flags);
 	}
-
-	if (last_q && last_q != locked_q)
-		spin_unlock(last_q->queue_lock);
-
-	spin_unlock_irqrestore(&ioc->lock, flags);
-
-	/* if no icq is left, we're done; otherwise, kick release_work */
-	if (hlist_empty(&ioc->icq_list))
-		kmem_cache_free(iocontext_cachep, ioc);
-	else
-		schedule_work(&ioc->release_work);
 }
 EXPORT_SYMBOL(put_io_context);
 
@@ -236,7 +175,7 @@ void exit_io_context(struct task_struct *task)
 	task_unlock(task);
 
 	atomic_dec(&ioc->nr_tasks);
-	put_io_context(ioc, NULL);
+	put_io_context(ioc);
 }
 
 /**
diff --git a/block/blk-merge.c b/block/blk-merge.c
index cfcc37cb222b..160035f54882 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -471,3 +471,40 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 {
 	return attempt_merge(q, rq, next);
 }
+
+bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
+{
+	if (!rq_mergeable(rq))
+		return false;
+
+	/* don't merge file system requests and discard requests */
+	if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD))
+		return false;
+
+	/* don't merge discard requests and secure discard requests */
+	if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
+		return false;
+
+	/* different data direction or already started, don't merge */
+	if (bio_data_dir(bio) != rq_data_dir(rq))
+		return false;
+
+	/* must be same device and not a special request */
+	if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
+		return false;
+
+	/* only merge integrity protected bio into ditto rq */
+	if (bio_integrity(bio) != blk_integrity_rq(rq))
+		return false;
+
+	return true;
+}
+
+int blk_try_merge(struct request *rq, struct bio *bio)
+{
+	if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_sector)
+		return ELEVATOR_BACK_MERGE;
+	else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_sector)
+		return ELEVATOR_FRONT_MERGE;
+	return ELEVATOR_NO_MERGE;
+}
diff --git a/block/blk.h b/block/blk.h
index 7efd772336de..9c12f80882b0 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -137,6 +137,8 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 				struct request *next);
 void blk_recalc_rq_segments(struct request *rq);
 void blk_rq_set_mixed_merge(struct request *rq);
+bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
+int blk_try_merge(struct request *rq, struct bio *bio);
 
 void blk_queue_congestion_threshold(struct request_queue *q);
 
diff --git a/block/bsg.c b/block/bsg.c
index 4cf703fd98bb..ff64ae3bacee 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -983,7 +983,8 @@ void bsg_unregister_queue(struct request_queue *q)
 
 	mutex_lock(&bsg_mutex);
 	idr_remove(&bsg_minor_idr, bcd->minor);
-	sysfs_remove_link(&q->kobj, "bsg");
+	if (q->kobj.sd)
+		sysfs_remove_link(&q->kobj, "bsg");
 	device_unregister(bcd->class_dev);
 	bcd->class_dev = NULL;
 	kref_put(&bcd->ref, bsg_kref_release_function);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index ee55019066a1..d0ba50533668 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1699,18 +1699,11 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
 
 	/*
 	 * Lookup the cfqq that this bio will be queued with and allow
-	 * merge only if rq is queued there.  This function can be called
-	 * from plug merge without queue_lock.  In such cases, ioc of @rq
-	 * and %current are guaranteed to be equal.  Avoid lookup which
-	 * requires queue_lock by using @rq's cic.
+	 * merge only if rq is queued there.
 	 */
-	if (current->io_context == RQ_CIC(rq)->icq.ioc) {
-		cic = RQ_CIC(rq);
-	} else {
-		cic = cfq_cic_lookup(cfqd, current->io_context);
-		if (!cic)
-			return false;
-	}
+	cic = cfq_cic_lookup(cfqd, current->io_context);
+	if (!cic)
+		return false;
 
 	cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
 	return cfqq == RQ_CFQQ(rq);
@@ -1794,7 +1787,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		cfqd->active_queue = NULL;
 
 	if (cfqd->active_cic) {
-		put_io_context(cfqd->active_cic->icq.ioc, cfqd->queue);
+		put_io_context(cfqd->active_cic->icq.ioc);
 		cfqd->active_cic = NULL;
 	}
 }
@@ -3117,17 +3110,18 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
  */
 static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
+	enum wl_type_t old_type = cfqq_type(cfqd->active_queue);
+
 	cfq_log_cfqq(cfqd, cfqq, "preempt");
+	cfq_slice_expired(cfqd, 1);
 
 	/*
 	 * workload type is changed, don't save slice, otherwise preempt
 	 * doesn't happen
 	 */
-	if (cfqq_type(cfqd->active_queue) != cfqq_type(cfqq))
+	if (old_type != cfqq_type(cfqq))
 		cfqq->cfqg->saved_workload_slice = 0;
 
-	cfq_slice_expired(cfqd, 1);
-
 	/*
 	 * Put the new queue at the front of the of the current list,
 	 * so we know that it will be selected next.
diff --git a/block/elevator.c b/block/elevator.c
index 91e18f8af9be..f016855a46b0 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -70,39 +70,9 @@ static int elv_iosched_allow_merge(struct request *rq, struct bio *bio)
 /*
  * can we safely merge with this request?
  */
-int elv_rq_merge_ok(struct request *rq, struct bio *bio)
+bool elv_rq_merge_ok(struct request *rq, struct bio *bio)
 {
-	if (!rq_mergeable(rq))
-		return 0;
-
-	/*
-	 * Don't merge file system requests and discard requests
-	 */
-	if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD))
-		return 0;
-
-	/*
-	 * Don't merge discard requests and secure discard requests
-	 */
-	if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
-		return 0;
-
-	/*
-	 * different data direction or already started, don't merge
-	 */
-	if (bio_data_dir(bio) != rq_data_dir(rq))
-		return 0;
-
-	/*
-	 * must be same device and not a special request
-	 */
-	if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
-		return 0;
-
-	/*
-	 * only merge integrity protected bio into ditto rq
-	 */
-	if (bio_integrity(bio) != blk_integrity_rq(rq))
+	if (!blk_rq_merge_ok(rq, bio))
 		return 0;
 
 	if (!elv_iosched_allow_merge(rq, bio))
@@ -112,23 +82,6 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio)
 }
 EXPORT_SYMBOL(elv_rq_merge_ok);
 
-int elv_try_merge(struct request *__rq, struct bio *bio)
-{
-	int ret = ELEVATOR_NO_MERGE;
-
-	/*
-	 * we can merge and sequence is ok, check if it's possible
-	 */
-	if (elv_rq_merge_ok(__rq, bio)) {
-		if (blk_rq_pos(__rq) + blk_rq_sectors(__rq) == bio->bi_sector)
-			ret = ELEVATOR_BACK_MERGE;
-		else if (blk_rq_pos(__rq) - bio_sectors(bio) == bio->bi_sector)
-			ret = ELEVATOR_FRONT_MERGE;
-	}
-
-	return ret;
-}
-
 static struct elevator_type *elevator_find(const char *name)
 {
 	struct elevator_type *e;
@@ -478,8 +431,8 @@ int elv_merge(struct request_queue *q, struct request **req, struct bio *bio)
 	/*
 	 * First try one-hit cache.
 	 */
-	if (q->last_merge) {
-		ret = elv_try_merge(q->last_merge, bio);
+	if (q->last_merge && elv_rq_merge_ok(q->last_merge, bio)) {
+		ret = blk_try_merge(q->last_merge, bio);
 		if (ret != ELEVATOR_NO_MERGE) {
 			*req = q->last_merge;
 			return ret;
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 510fb10ec45a..9baf11e86362 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4368,8 +4368,14 @@ out_unreg_blkdev:
 out_put_disk:
 	while (dr--) {
 		del_timer_sync(&motor_off_timer[dr]);
-		if (disks[dr]->queue)
+		if (disks[dr]->queue) {
 			blk_cleanup_queue(disks[dr]->queue);
+			/*
+			 * put_disk() is not paired with add_disk() and
+			 * will put queue reference one extra time. fix it.
+			 */
+			disks[dr]->queue = NULL;
+		}
 		put_disk(disks[dr]);
 	}
 	return err;
@@ -4579,6 +4585,15 @@ static void __exit floppy_module_exit(void)
 			platform_device_unregister(&floppy_device[drive]);
 		}
 		blk_cleanup_queue(disks[drive]->queue);
+
+		/*
+		 * These disks have not called add_disk().  Don't put down
+		 * queue reference in put_disk().
+		 */
+		if (!(allowed_drive_mask & (1 << drive)) ||
+		    fdc_state[FDC(drive)].version == FDC_NONE)
+			disks[drive]->queue = NULL;
+
 		put_disk(disks[drive]);
 	}
 
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f00257782fcc..cd504353b278 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -356,14 +356,14 @@ lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)
 	return __splice_from_pipe(pipe, sd, lo_splice_actor);
 }
 
-static int
+static ssize_t
 do_lo_receive(struct loop_device *lo,
 	      struct bio_vec *bvec, int bsize, loff_t pos)
 {
 	struct lo_read_data cookie;
 	struct splice_desc sd;
 	struct file *file;
-	long retval;
+	ssize_t retval;
 
 	cookie.lo = lo;
 	cookie.page = bvec->bv_page;
@@ -379,26 +379,28 @@ do_lo_receive(struct loop_device *lo,
 	file = lo->lo_backing_file;
 	retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);
 
-	if (retval < 0)
-		return retval;
-	if (retval != bvec->bv_len)
-		return -EIO;
-	return 0;
+	return retval;
 }
 
 static int
 lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
 {
 	struct bio_vec *bvec;
-	int i, ret = 0;
+	ssize_t s;
+	int i;
 
 	bio_for_each_segment(bvec, bio, i) {
-		ret = do_lo_receive(lo, bvec, bsize, pos);
-		if (ret < 0)
+		s = do_lo_receive(lo, bvec, bsize, pos);
+		if (s < 0)
+			return s;
+
+		if (s != bvec->bv_len) {
+			zero_fill_bio(bio);
 			break;
+		}
 		pos += bvec->bv_len;
 	}
-	return ret;
+	return 0;
 }
 
 static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index b74eab70c3d0..8eb81c96608f 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -2068,8 +2068,6 @@ static int mtip_hw_ioctl(struct driver_data *dd, unsigned int cmd,
  *	     when the read completes.
  * @data     Callback data passed to the callback function
  *	     when the read completes.
- * @barrier  If non-zero, this command must be completed before
- *	     issuing any other commands.
  * @dir      Direction (read or write)
  *
  * return value
@@ -2077,7 +2075,7 @@ static int mtip_hw_ioctl(struct driver_data *dd, unsigned int cmd,
  */
 static void mtip_hw_submit_io(struct driver_data *dd, sector_t start,
 			      int nsect, int nents, int tag, void *callback,
-			      void *data, int barrier, int dir)
+			      void *data, int dir)
 {
 	struct host_to_dev_fis	*fis;
 	struct mtip_port *port = dd->port;
@@ -2108,8 +2106,6 @@ static void mtip_hw_submit_io(struct driver_data *dd, sector_t start,
 	*((unsigned int *) &fis->lba_low) = (start & 0xFFFFFF);
 	*((unsigned int *) &fis->lba_low_ex) = ((start >> 24) & 0xFFFFFF);
 	fis->device	 = 1 << 6;
-	if (barrier)
-		fis->device |= FUA_BIT;
 	fis->features    = nsect & 0xFF;
 	fis->features_ex = (nsect >> 8) & 0xFF;
 	fis->sect_count  = ((tag << 3) | (tag >> 5));
@@ -3087,7 +3083,6 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio)
 				tag,
 				bio_endio,
 				bio,
-				bio->bi_rw & REQ_FUA,
 				bio_data_dir(bio));
 	} else
 		bio_io_error(bio);
@@ -3187,6 +3182,10 @@ skip_create_disk:
 	blk_queue_max_segments(dd->queue, MTIP_MAX_SG);
 	blk_queue_physical_block_size(dd->queue, 4096);
 	blk_queue_io_min(dd->queue, 4096);
+	/*
+	 * write back cache is not supported in the device. FUA depends on
+	 * write back cache support, hence setting flush support to zero.
+	 */
 	blk_queue_flush(dd->queue, 0);
 
 	/* Set the capacity of the device in 512 byte sectors. */
diff --git a/drivers/block/mtip32xx/mtip32xx.h b/drivers/block/mtip32xx/mtip32xx.h
index 723d7c4946dc..e0554a8f2233 100644
--- a/drivers/block/mtip32xx/mtip32xx.h
+++ b/drivers/block/mtip32xx/mtip32xx.h
@@ -104,9 +104,6 @@
 /* BAR number used to access the HBA registers. */
 #define MTIP_ABAR		5
 
-/* Forced Unit Access Bit */
-#define FUA_BIT			0x80
-
 #ifdef DEBUG
  #define dbg_printk(format, arg...)	\
 	printk(pr_fmt(format), ##arg);
@@ -415,8 +412,6 @@ struct driver_data {
 
 	atomic_t resumeflag; /* Atomic variable to track suspend/resume */
 
-	atomic_t eh_active; /* Flag for error handling tracking */
-
 	struct task_struct *mtip_svc_handler; /* task_struct of svc thd */
 };
 
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 55eaf474d32c..d620b4495745 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -286,8 +286,6 @@
 
 /* used to tell the module to turn on full debugging messages */
 static bool debug;
-/* used to keep tray locked at all times */
-static int keeplocked;
 /* default compatibility mode */
 static bool autoclose=1;
 static bool autoeject;
@@ -1204,7 +1202,7 @@ void cdrom_release(struct cdrom_device_info *cdi, fmode_t mode)
 		cdinfo(CD_CLOSE, "Use count for \"/dev/%s\" now zero\n", cdi->name);
 		cdrom_dvd_rw_close_write(cdi);
 
-		if ((cdo->capability & CDC_LOCK) && !keeplocked) {
+		if ((cdo->capability & CDC_LOCK) && !cdi->keeplocked) {
 			cdinfo(CD_CLOSE, "Unlocking door!\n");
 			cdo->lock_door(cdi, 0);
 		}
@@ -1371,7 +1369,7 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
 	curslot = info->hdr.curslot;
 	kfree(info);
 
-	if (cdi->use_count > 1 || keeplocked) {
+	if (cdi->use_count > 1 || cdi->keeplocked) {
 		if (slot == CDSL_CURRENT) {
 	    		return curslot;
 		} else {
@@ -2119,11 +2117,6 @@ static int cdrom_read_cdda_old(struct cdrom_device_info *cdi, __u8 __user *ubuf,
 	if (!nr)
 		return -ENOMEM;
 
-	if (!access_ok(VERIFY_WRITE, ubuf, nframes * CD_FRAMESIZE_RAW)) {
-		ret = -EFAULT;
-		goto out;
-	}
-
 	cgc.data_direction = CGC_DATA_READ;
 	while (nframes > 0) {
 		if (nr > nframes)
@@ -2132,7 +2125,7 @@ static int cdrom_read_cdda_old(struct cdrom_device_info *cdi, __u8 __user *ubuf,
 		ret = cdrom_read_block(cdi, &cgc, lba, nr, 1, CD_FRAMESIZE_RAW);
 		if (ret)
 			break;
-		if (__copy_to_user(ubuf, cgc.buffer, CD_FRAMESIZE_RAW * nr)) {
+		if (copy_to_user(ubuf, cgc.buffer, CD_FRAMESIZE_RAW * nr)) {
 			ret = -EFAULT;
 			break;
 		}
@@ -2140,7 +2133,6 @@ static int cdrom_read_cdda_old(struct cdrom_device_info *cdi, __u8 __user *ubuf,
 		nframes -= nr;
 		lba += nr;
 	}
-out:
 	kfree(cgc.buffer);
 	return ret;
 }
@@ -2295,7 +2287,7 @@ static int cdrom_ioctl_eject(struct cdrom_device_info *cdi)
 
 	if (!CDROM_CAN(CDC_OPEN_TRAY))
 		return -ENOSYS;
-	if (cdi->use_count != 1 || keeplocked)
+	if (cdi->use_count != 1 || cdi->keeplocked)
 		return -EBUSY;
 	if (CDROM_CAN(CDC_LOCK)) {
 		int ret = cdi->ops->lock_door(cdi, 0);
@@ -2322,7 +2314,7 @@ static int cdrom_ioctl_eject_sw(struct cdrom_device_info *cdi,
 
 	if (!CDROM_CAN(CDC_OPEN_TRAY))
 		return -ENOSYS;
-	if (keeplocked)
+	if (cdi->keeplocked)
 		return -EBUSY;
 
 	cdi->options &= ~(CDO_AUTO_CLOSE | CDO_AUTO_EJECT);
@@ -2453,7 +2445,7 @@ static int cdrom_ioctl_lock_door(struct cdrom_device_info *cdi,
 	if (!CDROM_CAN(CDC_LOCK))
 		return -EDRIVE_CANT_DO_THIS;
 
-	keeplocked = arg ? 1 : 0;
+	cdi->keeplocked = arg ? 1 : 0;
 
 	/*
 	 * Don't unlock the door on multiple opens by default, but allow
diff --git a/fs/bio.c b/fs/bio.c
index b1fe82cf88cf..b980ecde026a 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -505,13 +505,9 @@ EXPORT_SYMBOL(bio_clone);
 int bio_get_nr_vecs(struct block_device *bdev)
 {
 	struct request_queue *q = bdev_get_queue(bdev);
-	int nr_pages;
-
-	nr_pages = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	if (nr_pages > queue_max_segments(q))
-		nr_pages = queue_max_segments(q);
-
-	return nr_pages;
+	return min_t(unsigned,
+		     queue_max_segments(q),
+		     queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
 }
 EXPORT_SYMBOL(bio_get_nr_vecs);
 
diff --git a/fs/ioprio.c b/fs/ioprio.c
index f84b380d65e5..0f1b9515213b 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -51,7 +51,7 @@ int set_task_ioprio(struct task_struct *task, int ioprio)
 	ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
 	if (ioc) {
 		ioc_ioprio_changed(ioc, ioprio);
-		put_io_context(ioc, NULL);
+		put_io_context(ioc);
 	}
 
 	return err;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6c6a1f008065..606cf339bb56 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -399,9 +399,6 @@ struct request_queue {
 	/* Throttle data */
 	struct throtl_data *td;
 #endif
-#ifdef CONFIG_LOCKDEP
-	int			ioc_release_depth;
-#endif
 };
 
 #define QUEUE_FLAG_QUEUED	1	/* uses generic tag queueing */
diff --git a/include/linux/cdrom.h b/include/linux/cdrom.h
index 35eae4b67503..7c48029dffe6 100644
--- a/include/linux/cdrom.h
+++ b/include/linux/cdrom.h
@@ -952,7 +952,8 @@ struct cdrom_device_info {
     	char name[20];                  /* name of the device type */
 /* per-device flags */
         __u8 sanyo_slot		: 2;	/* Sanyo 3 CD changer support */
-        __u8 reserved		: 6;	/* not used yet */
+        __u8 keeplocked		: 1;	/* CDROM_LOCKDOOR status */
+        __u8 reserved		: 5;	/* not used yet */
 	int cdda_method;		/* see flags */
 	__u8 last_sense;
 	__u8 media_written;		/* dirty flag, DVD+RW bookkeeping */
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index c24f3d7fbf1e..7d4e0356f329 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -42,12 +42,6 @@ struct elevator_ops
 	elevator_merged_fn *elevator_merged_fn;
 	elevator_merge_req_fn *elevator_merge_req_fn;
 	elevator_allow_merge_fn *elevator_allow_merge_fn;
-
-	/*
-	 * Used for both plugged list and elevator merging and in the
-	 * former case called without queue_lock.  Read comment on top of
-	 * attempt_plug_merge() for details.
-	 */
 	elevator_bio_merged_fn *elevator_bio_merged_fn;
 
 	elevator_dispatch_fn *elevator_dispatch_fn;
@@ -122,7 +116,6 @@ extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
 extern void elv_add_request(struct request_queue *, struct request *, int);
 extern void __elv_add_request(struct request_queue *, struct request *, int);
 extern int elv_merge(struct request_queue *, struct request **, struct bio *);
-extern int elv_try_merge(struct request *, struct bio *);
 extern void elv_merge_requests(struct request_queue *, struct request *,
 			       struct request *);
 extern void elv_merged_request(struct request_queue *, struct request *, int);
@@ -155,7 +148,7 @@ extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
 extern int elevator_init(struct request_queue *, char *);
 extern void elevator_exit(struct elevator_queue *);
 extern int elevator_change(struct request_queue *, const char *);
-extern int elv_rq_merge_ok(struct request *, struct bio *);
+extern bool elv_rq_merge_ok(struct request *, struct bio *);
 
 /*
  * Helper functions.
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index 7e1371c4bccf..119773eebe31 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -133,7 +133,7 @@ static inline struct io_context *ioc_task_link(struct io_context *ioc)
 
 struct task_struct;
 #ifdef CONFIG_BLOCK
-void put_io_context(struct io_context *ioc, struct request_queue *locked_q);
+void put_io_context(struct io_context *ioc);
 void exit_io_context(struct task_struct *task);
 struct io_context *get_task_io_context(struct task_struct *task,
 				       gfp_t gfp_flags, int node);
@@ -141,8 +141,7 @@ void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
 void ioc_cgroup_changed(struct io_context *ioc);
 #else
 struct io_context;
-static inline void put_io_context(struct io_context *ioc,
-				  struct request_queue *locked_q) { }
+static inline void put_io_context(struct io_context *ioc) { }
 static inline void exit_io_context(struct task_struct *task) { }
 #endif
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 1b2ef3c23ae4..b77fd559c78e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -910,7 +910,7 @@ static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
 			return -ENOMEM;
 
 		new_ioc->ioprio = ioc->ioprio;
-		put_io_context(new_ioc, NULL);
+		put_io_context(new_ioc);
 	}
 #endif
 	return 0;
diff --git a/kernel/relay.c b/kernel/relay.c
index 4335e1d7ee2d..ab56a1764d4d 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -164,10 +164,14 @@ depopulate:
  */
 static struct rchan_buf *relay_create_buf(struct rchan *chan)
 {
-	struct rchan_buf *buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
-	if (!buf)
+	struct rchan_buf *buf;
+
+	if (chan->n_subbufs > UINT_MAX / sizeof(size_t *))
 		return NULL;
 
+	buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
+	if (!buf)
+		return NULL;
 	buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
 	if (!buf->padding)
 		goto free_buf;
@@ -574,6 +578,8 @@ struct rchan *relay_open(const char *base_filename,
 
 	if (!(subbuf_size && n_subbufs))
 		return NULL;
+	if (subbuf_size > UINT_MAX / n_subbufs)
+		return NULL;
 
 	chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
 	if (!chan)