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From 8ba3db6f9244e6911ac88380cd133f39aaba95ab Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 13 Mar 2018 13:49:16 +0100
Subject: [PATCH 284/347] block: blk-mq: move blk_queue_usage_counter_release()
into process context
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
[ Upstream commit 61c928ecf4fe200bda9b49a0813b5ba0f43995b5 ]
| BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:914
| in_atomic(): 1, irqs_disabled(): 0, pid: 255, name: kworker/u257:6
| 5 locks held by kworker/u257:6/255:
| #0: ("events_unbound"){.+.+.+}, at: [<ffffffff8108edf1>] process_one_work+0x171/0x5e0
| #1: ((&entry->work)){+.+.+.}, at: [<ffffffff8108edf1>] process_one_work+0x171/0x5e0
| #2: (&shost->scan_mutex){+.+.+.}, at: [<ffffffffa000faa3>] __scsi_add_device+0xa3/0x130 [scsi_mod]
| #3: (&set->tag_list_lock){+.+...}, at: [<ffffffff812f09fa>] blk_mq_init_queue+0x96a/0xa50
| #4: (rcu_read_lock_sched){......}, at: [<ffffffff8132887d>] percpu_ref_kill_and_confirm+0x1d/0x120
| Preemption disabled at:[<ffffffff812eff76>] blk_mq_freeze_queue_start+0x56/0x70
|
| CPU: 2 PID: 255 Comm: kworker/u257:6 Not tainted 3.18.7-rt0+ #1
| Workqueue: events_unbound async_run_entry_fn
| 0000000000000003 ffff8800bc29f998 ffffffff815b3a12 0000000000000000
| 0000000000000000 ffff8800bc29f9b8 ffffffff8109aa16 ffff8800bc29fa28
| ffff8800bc5d1bc8 ffff8800bc29f9e8 ffffffff815b8dd4 ffff880000000000
| Call Trace:
| [<ffffffff815b3a12>] dump_stack+0x4f/0x7c
| [<ffffffff8109aa16>] __might_sleep+0x116/0x190
| [<ffffffff815b8dd4>] rt_spin_lock+0x24/0x60
| [<ffffffff810b6089>] __wake_up+0x29/0x60
| [<ffffffff812ee06e>] blk_mq_usage_counter_release+0x1e/0x20
| [<ffffffff81328966>] percpu_ref_kill_and_confirm+0x106/0x120
| [<ffffffff812eff76>] blk_mq_freeze_queue_start+0x56/0x70
| [<ffffffff812f0000>] blk_mq_update_tag_set_depth+0x40/0xd0
| [<ffffffff812f0a1c>] blk_mq_init_queue+0x98c/0xa50
| [<ffffffffa000dcf0>] scsi_mq_alloc_queue+0x20/0x60 [scsi_mod]
| [<ffffffffa000ea35>] scsi_alloc_sdev+0x2f5/0x370 [scsi_mod]
| [<ffffffffa000f494>] scsi_probe_and_add_lun+0x9e4/0xdd0 [scsi_mod]
| [<ffffffffa000fb26>] __scsi_add_device+0x126/0x130 [scsi_mod]
| [<ffffffffa013033f>] ata_scsi_scan_host+0xaf/0x200 [libata]
| [<ffffffffa012b5b6>] async_port_probe+0x46/0x60 [libata]
| [<ffffffff810978fb>] async_run_entry_fn+0x3b/0xf0
| [<ffffffff8108ee81>] process_one_work+0x201/0x5e0
percpu_ref_kill_and_confirm() invokes blk_mq_usage_counter_release() in
a rcu-sched region. swait based wake queue can't be used due to
wake_up_all() usage and disabled interrupts in !RT configs (as reported
by Corey Minyard).
The wq_has_sleeper() check has been suggested by Peter Zijlstra.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
block/blk-core.c | 12 +++++++++++-
include/linux/blkdev.h | 2 ++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 461a93c08c14..a67a50dd714a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -973,12 +973,21 @@ void blk_queue_exit(struct request_queue *q)
percpu_ref_put(&q->q_usage_counter);
}
+static void blk_queue_usage_counter_release_wrk(struct kthread_work *work)
+{
+ struct request_queue *q =
+ container_of(work, struct request_queue, mq_pcpu_wake);
+
+ wake_up_all(&q->mq_freeze_wq);
+}
+
static void blk_queue_usage_counter_release(struct percpu_ref *ref)
{
struct request_queue *q =
container_of(ref, struct request_queue, q_usage_counter);
- wake_up_all(&q->mq_freeze_wq);
+ if (wq_has_sleeper(&q->mq_freeze_wq))
+ kthread_schedule_work(&q->mq_pcpu_wake);
}
static void blk_rq_timed_out_timer(struct timer_list *t)
@@ -1078,6 +1087,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id,
queue_flag_set_unlocked(QUEUE_FLAG_BYPASS, q);
init_waitqueue_head(&q->mq_freeze_wq);
+ kthread_init_work(&q->mq_pcpu_wake, blk_queue_usage_counter_release_wrk);
/*
* Init percpu_ref in atomic mode so that it's faster to shutdown.
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 39d90bf9b5fa..5566d0049c22 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -13,6 +13,7 @@
#include <linux/llist.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
+#include <linux/kthread.h>
#include <linux/pagemap.h>
#include <linux/backing-dev-defs.h>
#include <linux/wait.h>
@@ -664,6 +665,7 @@ struct request_queue {
#endif
struct rcu_head rcu_head;
wait_queue_head_t mq_freeze_wq;
+ struct kthread_work mq_pcpu_wake;
struct percpu_ref q_usage_counter;
struct list_head all_q_node;
--
2.36.1
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