From 8d91c1e411f55d7ea91b1183a2e9f8088fb4d5be Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Tue, 15 Dec 2015 14:52:16 -0300
Subject: Linux-libre 4.3.2-gnu

---
 block/blk-mq-sysfs.c | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

(limited to 'block/blk-mq-sysfs.c')

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 279c5d674..788fffd9b 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -229,8 +229,6 @@ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 	unsigned int i, first = 1;
 	ssize_t ret = 0;
 
-	blk_mq_disable_hotplug();
-
 	for_each_cpu(i, hctx->cpumask) {
 		if (first)
 			ret += sprintf(ret + page, "%u", i);
@@ -240,8 +238,6 @@ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 		first = 0;
 	}
 
-	blk_mq_enable_hotplug();
-
 	ret += sprintf(ret + page, "\n");
 	return ret;
 }
@@ -343,7 +339,7 @@ static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 	struct blk_mq_ctx *ctx;
 	int i;
 
-	if (!hctx->nr_ctx || !(hctx->flags & BLK_MQ_F_SYSFS_UP))
+	if (!hctx->nr_ctx)
 		return;
 
 	hctx_for_each_ctx(hctx, ctx, i)
@@ -358,7 +354,7 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
 	struct blk_mq_ctx *ctx;
 	int i, ret;
 
-	if (!hctx->nr_ctx || !(hctx->flags & BLK_MQ_F_SYSFS_UP))
+	if (!hctx->nr_ctx)
 		return 0;
 
 	ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", hctx->queue_num);
@@ -381,6 +377,8 @@ void blk_mq_unregister_disk(struct gendisk *disk)
 	struct blk_mq_ctx *ctx;
 	int i, j;
 
+	blk_mq_disable_hotplug();
+
 	queue_for_each_hw_ctx(q, hctx, i) {
 		blk_mq_unregister_hctx(hctx);
 
@@ -395,6 +393,9 @@ void blk_mq_unregister_disk(struct gendisk *disk)
 	kobject_put(&q->mq_kobj);
 
 	kobject_put(&disk_to_dev(disk)->kobj);
+
+	q->mq_sysfs_init_done = false;
+	blk_mq_enable_hotplug();
 }
 
 static void blk_mq_sysfs_init(struct request_queue *q)
@@ -425,27 +426,30 @@ int blk_mq_register_disk(struct gendisk *disk)
 	struct blk_mq_hw_ctx *hctx;
 	int ret, i;
 
+	blk_mq_disable_hotplug();
+
 	blk_mq_sysfs_init(q);
 
 	ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
 	if (ret < 0)
-		return ret;
+		goto out;
 
 	kobject_uevent(&q->mq_kobj, KOBJ_ADD);
 
 	queue_for_each_hw_ctx(q, hctx, i) {
-		hctx->flags |= BLK_MQ_F_SYSFS_UP;
 		ret = blk_mq_register_hctx(hctx);
 		if (ret)
 			break;
 	}
 
-	if (ret) {
+	if (ret)
 		blk_mq_unregister_disk(disk);
-		return ret;
-	}
+	else
+		q->mq_sysfs_init_done = true;
+out:
+	blk_mq_enable_hotplug();
 
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(blk_mq_register_disk);
 
@@ -454,6 +458,9 @@ void blk_mq_sysfs_unregister(struct request_queue *q)
 	struct blk_mq_hw_ctx *hctx;
 	int i;
 
+	if (!q->mq_sysfs_init_done)
+		return;
+
 	queue_for_each_hw_ctx(q, hctx, i)
 		blk_mq_unregister_hctx(hctx);
 }
@@ -463,6 +470,9 @@ int blk_mq_sysfs_register(struct request_queue *q)
 	struct blk_mq_hw_ctx *hctx;
 	int i, ret = 0;
 
+	if (!q->mq_sysfs_init_done)
+		return ret;
+
 	queue_for_each_hw_ctx(q, hctx, i) {
 		ret = blk_mq_register_hctx(hctx);
 		if (ret)
-- 
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