[PATCH 4.9 109/148] blk-mq: initialize mq kobjects in blk_mq_init_allocated_queue()

Greg Kroah-Hartman
2017-12-12T13:11:48Z

From: Ming Lei <tom.leiming@gmail.com>

[ Upstream commit 737f98cfe7de8df7433a4d846850aa8efa44bd48 ]

Both q->mq_kobj and sw queues' kobjects should have been initialized
once, instead of doing that each add_disk context.

Also this patch removes clearing of ctx in blk_mq_init_cpu_queues()
because percpu allocator fills zero to allocated variable.

This patch fixes one issue[1] reported from Omar.

[1] kernel wearning when doing unbind/bind on one scsi-mq device

[ 19.347924] kobject (ffff8800791ea0b8): tried to init an initialized object, something is seriously wrong.
[ 19.349781] CPU: 1 PID: 84 Comm: kworker/u8:1 Not tainted 4.10.0-rc7-00210-g53f39eeaa263 #34
[ 19.350686] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-20161122_114906-anatol 04/01/2014
[ 19.350920] Workqueue: events_unbound async_run_entry_fn
[ 19.350920] Call Trace:
[ 19.350920] dump_stack+0x63/0x83
[ 19.350920] kobject_init+0x77/0x90
[ 19.350920] blk_mq_register_dev+0x40/0x130
[ 19.350920] blk_register_queue+0xb6/0x190
[ 19.350920] device_add_disk+0x1ec/0x4b0
[ 19.350920] sd_probe_async+0x10d/0x1c0 [sd_mod]
[ 19.350920] async_run_entry_fn+0x48/0x150
[ 19.350920] process_one_work+0x1d0/0x480
[ 19.350920] worker_thread+0x48/0x4e0
[ 19.350920] kthread+0x101/0x140
[ 19.350920] ? process_one_work+0x480/0x480
[ 19.350920] ? kthread_create_on_node+0x60/0x60
[ 19.350920] ret_from_fork+0x2c/0x40

Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
block/blk-mq-sysfs.c | 4 +---
block/blk-mq.c | 4 +++-
block/blk-mq.h | 1 +
3 files changed, 5 insertions(+), 4 deletions(-)

--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -429,7 +429,7 @@ void blk_mq_hctx_kobj_init(struct blk_mq
kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
}

-static void blk_mq_sysfs_init(struct request_queue *q)
+void blk_mq_sysfs_init(struct request_queue *q)
{
struct blk_mq_ctx *ctx;
int cpu;
@@ -449,8 +449,6 @@ int blk_mq_register_dev(struct device *d

blk_mq_disable_hotplug();

- blk_mq_sysfs_init(q);
-
ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
if (ret < 0)
goto out;
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1707,7 +1707,6 @@ static void blk_mq_init_cpu_queues(struc
struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
struct blk_mq_hw_ctx *hctx;

- memset(__ctx, 0, sizeof(*__ctx));
__ctx->cpu = i;
spin_lock_init(&__ctx->lock);
INIT_LIST_HEAD(&__ctx->rq_list);
@@ -1970,6 +1969,9 @@ struct request_queue *blk_mq_init_alloca
if (!q->queue_ctx)
goto err_exit;

+ /* init q->mq_kobj and sw queues' kobjects */
+ blk_mq_sysfs_init(q);
+
q->queue_hw_ctx = kzalloc_node(nr_cpu_ids * sizeof(*(q->queue_hw_ctx)),
GFP_KERNEL, set->numa_node);
if (!q->queue_hw_ctx)
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -50,6 +50,7 @@ static inline struct blk_mq_hw_ctx *blk_
/*
* sysfs helpers
*/
+extern void blk_mq_sysfs_init(struct request_queue *q);
extern int blk_mq_sysfs_register(struct request_queue *q);
extern void blk_mq_sysfs_unregister(struct request_queue *q);
extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);