Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Conflicts:
	drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c

Small minor conflict in bnx2x, wherein one commit changed how
statistics were stored in software, and another commit
fixed endianness bugs wrt. reading the values provided by
the chip in memory.

Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 97 insertions, 170 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;