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

Pull two block layer fixes from Jens Axboe:
 "Two small patches that should make it into 3.19:

   - a fixup from me for NVMe, making the cq_vector a signed variable.
     Otherwise our -1 comparison fails, and commit 2b25d981 doesn't
     do what it was supposed to.

   - a fixup for the hotplug handling for blk-mq from Ming Lei, using
     the proper kobject referencing to ensure we release resources at
     the right time"

* 'for-linus' of git://git.kernel.dk/linux-block:
  blk-mq: fix hctx/ctx kobject use-after-free
  NVMe: cq_vector should be signed

block/blk-mq-sysfs.c

@@ -15,6 +15,26 @@
 
 static void blk_mq_sysfs_release(struct kobject *kobj)
 {
+	struct request_queue *q;
+
+	q = container_of(kobj, struct request_queue, mq_kobj);
+	free_percpu(q->queue_ctx);
+}
+
+static void blk_mq_ctx_release(struct kobject *kobj)
+{
+	struct blk_mq_ctx *ctx;
+
+	ctx = container_of(kobj, struct blk_mq_ctx, kobj);
+	kobject_put(&ctx->queue->mq_kobj);
+}
+
+static void blk_mq_hctx_release(struct kobject *kobj)
+{
+	struct blk_mq_hw_ctx *hctx;
+
+	hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
+	kfree(hctx);
 }
 
 struct blk_mq_ctx_sysfs_entry {
@@ -318,13 +338,13 @@ static struct kobj_type blk_mq_ktype = {
 static struct kobj_type blk_mq_ctx_ktype = {
 	.sysfs_ops	= &blk_mq_sysfs_ops,
 	.default_attrs	= default_ctx_attrs,
-	.release	= blk_mq_sysfs_release,
+	.release	= blk_mq_ctx_release,
 };
 
 static struct kobj_type blk_mq_hw_ktype = {
 	.sysfs_ops	= &blk_mq_hw_sysfs_ops,
 	.default_attrs	= default_hw_ctx_attrs,
-	.release	= blk_mq_sysfs_release,
+	.release	= blk_mq_hctx_release,
 };
 
 static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
@@ -355,6 +375,7 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
 		return ret;
 
 	hctx_for_each_ctx(hctx, ctx, i) {
+		kobject_get(&q->mq_kobj);
 		ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
 		if (ret)
 			break;

block/blk-mq.c

@@ -1641,10 +1641,8 @@ static void blk_mq_free_hw_queues(struct request_queue *q,
 	struct blk_mq_hw_ctx *hctx;
 	unsigned int i;
 
-	queue_for_each_hw_ctx(q, hctx, i) {
+	queue_for_each_hw_ctx(q, hctx, i)
 		free_cpumask_var(hctx->cpumask);
-		kfree(hctx);
-	}
 }
 
 static int blk_mq_init_hctx(struct request_queue *q,
@@ -2002,11 +2000,9 @@ void blk_mq_free_queue(struct request_queue *q)
 
 	percpu_ref_exit(&q->mq_usage_counter);
 
-	free_percpu(q->queue_ctx);
 	kfree(q->queue_hw_ctx);
 	kfree(q->mq_map);
 
-	q->queue_ctx = NULL;
 	q->queue_hw_ctx = NULL;
 	q->mq_map = NULL;
 

drivers/block/nvme-core.c

@@ -106,7 +106,7 @@ struct nvme_queue {
 	dma_addr_t cq_dma_addr;
 	u32 __iomem *q_db;
 	u16 q_depth;
-	u16 cq_vector;
+	s16 cq_vector;
 	u16 sq_head;
 	u16 sq_tail;
 	u16 cq_head;