Merge branch 'android-4.4-p' of https://android.googlesource.com/kernel/common into lineage-17.1-caf-msm8998

This brings LA.UM.8.4.r1-05500-8x98.0 up to date with
https://android.googlesource.com/kernel/common/ android-4.4-p at commit:
60fca75727065 Merge 4.4.226 into android-4.4-p

Conflicts:
	drivers/base/firmware_class.c
	drivers/gpu/drm/msm/msm_gem.c
	drivers/mmc/host/sdhci.c
	drivers/net/wireless/ath/ath10k/core.c
	kernel/trace/blktrace.c
	net/socket.c
	sound/core/rawmidi.c
	sound/usb/mixer.c

Change-Id: Ic8599e865656da72a9405c45f27091ec1ddc168c

4 files changed, 30 insertions, 2 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index ea1f8715c8f7..96433980aee4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -728,6 +728,9 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 
 	kobject_init(&q->kobj, &blk_queue_ktype);
 
+#ifdef CONFIG_BLK_DEV_IO_TRACE
+	mutex_init(&q->blk_trace_mutex);
+#endif
 	mutex_init(&q->sysfs_lock);
 	spin_lock_init(&q->__queue_lock);
 
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index a07ca3488d96..c1c654319287 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -481,6 +481,11 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
 	struct blk_mq_hw_ctx *hctx;
 	int i;
 
+	/*
+	 * Avoid potential races with things like queue removal.
+	 */
+	if (!percpu_ref_tryget(&q->q_usage_counter))
+		return;
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		struct blk_mq_tags *tags = hctx->tags;
@@ -497,7 +502,7 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
 		bt_for_each(hctx, &tags->bitmap_tags, tags->nr_reserved_tags, fn, priv,
 		      false);
 	}
-
+	blk_queue_exit(q);
 }
 
 static unsigned int bt_unused_tags(struct blk_mq_bitmap_tags *bt)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index d65ddc18d7e4..18d0a0270470 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -628,6 +628,22 @@ static void blk_mq_rq_timer(unsigned long priv)
 	};
 	int i;
 
+	/* A deadlock might occur if a request is stuck requiring a
+	 * timeout at the same time a queue freeze is waiting
+	 * completion, since the timeout code would not be able to
+	 * acquire the queue reference here.
+	 *
+	 * That's why we don't use blk_queue_enter here; instead, we use
+	 * percpu_ref_tryget directly, because we need to be able to
+	 * obtain a reference even in the short window between the queue
+	 * starting to freeze, by dropping the first reference in
+	 * blk_mq_freeze_queue_start, and the moment the last request is
+	 * consumed, marked by the instant q_usage_counter reaches
+	 * zero.
+	 */
+	if (!percpu_ref_tryget(&q->q_usage_counter))
+		return;
+
 	blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data);
 
 	if (data.next_set) {
@@ -642,6 +658,7 @@ static void blk_mq_rq_timer(unsigned long priv)
 				blk_mq_tag_idle(hctx);
 		}
 	}
+	blk_queue_exit(q);
 }
 
 /*
@@ -1491,7 +1508,7 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
 		int to_do;
 		void *p;
 
-		while (left < order_to_size(this_order - 1) && this_order)
+		while (this_order && left < order_to_size(this_order - 1))
 			this_order--;
 
 		do {
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index aa40aa93381b..2bc03df554a6 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -134,6 +134,8 @@ void blk_rq_timed_out_timer(unsigned long data)
 	struct request *rq, *tmp;
 	int next_set = 0;
 
+	if (blk_queue_enter(q, GFP_NOWAIT))
+		return;
 	spin_lock_irqsave(q->queue_lock, flags);
 
 	list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
@@ -143,6 +145,7 @@ void blk_rq_timed_out_timer(unsigned long data)
 		mod_timer(&q->timeout, round_jiffies_up(next));
 
 	spin_unlock_irqrestore(q->queue_lock, flags);
+	blk_queue_exit(q);
 }
 
 /**