Revert the patch series "Call blk_mq_free_tag_set() earlier" because it
introduces a deadlock if the scsi_remove_host() caller holds a reference
on a device, target or host.
Reported-by: syzbot+bafeb834708b1bb750bc@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: fe442604199e ("scsi: core: Make sure that targets outlive devices")
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/scsi_scan.c | 2 --
drivers/scsi/scsi_sysfs.c | 20 +++-----------------
include/scsi/scsi_device.h | 2 --
3 files changed, 3 insertions(+), 21 deletions(-)
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 4c1efd6a3b0c..91ac901a6682 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -521,8 +521,6 @@ static struct scsi_target *scsi_alloc_target(struct device *parent,
starget->state = STARGET_CREATED;
starget->scsi_level = SCSI_2;
starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED;
- init_waitqueue_head(&starget->sdev_wq);
-
retry:
spin_lock_irqsave(shost->host_lock, flags);
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 282b32781e8c..aa70d9282161 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -443,9 +443,7 @@ static void scsi_device_cls_release(struct device *class_dev)
static void scsi_device_dev_release_usercontext(struct work_struct *work)
{
- struct scsi_device *sdev = container_of(work, struct scsi_device,
- ew.work);
- struct scsi_target *starget = sdev->sdev_target;
+ struct scsi_device *sdev;
struct device *parent;
struct list_head *this, *tmp;
struct scsi_vpd *vpd_pg80 = NULL, *vpd_pg83 = NULL;
@@ -454,6 +452,8 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
unsigned long flags;
struct module *mod;
+ sdev = container_of(work, struct scsi_device, ew.work);
+
mod = sdev->host->hostt->module;
scsi_dh_release_device(sdev);
@@ -516,9 +516,6 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
kfree(sdev->inquiry);
kfree(sdev);
- if (starget && atomic_dec_return(&starget->sdev_count) == 0)
- wake_up(&starget->sdev_wq);
-
if (parent)
put_device(parent);
module_put(mod);
@@ -1538,14 +1535,6 @@ static void __scsi_remove_target(struct scsi_target *starget)
goto restart;
}
spin_unlock_irqrestore(shost->host_lock, flags);
-
- /*
- * After scsi_remove_target() returns its caller can remove resources
- * associated with @starget, e.g. an rport or session. Wait until all
- * devices associated with @starget have been removed to prevent that
- * a SCSI error handling callback function triggers a use-after-free.
- */
- wait_event(starget->sdev_wq, atomic_read(&starget->sdev_count) == 0);
}
/**
@@ -1656,9 +1645,6 @@ void scsi_sysfs_device_initialize(struct scsi_device *sdev)
list_add_tail(&sdev->same_target_siblings, &starget->devices);
list_add_tail(&sdev->siblings, &shost->__devices);
spin_unlock_irqrestore(shost->host_lock, flags);
-
- atomic_inc(&starget->sdev_count);
-
/*
* device can now only be removed via __scsi_remove_device() so hold
* the target. Target will be held in CREATED state until something
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 3113471ca375..2493bd65351a 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -309,8 +309,6 @@ struct scsi_target {
struct list_head devices;
struct device dev;
struct kref reap_ref; /* last put renders target invisible */
- atomic_t sdev_count;
- wait_queue_head_t sdev_wq;
unsigned int channel;
unsigned int id; /* target id ... replace
* scsi_device.id eventually */
