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nvme: change locking for the per-subsystem controller list

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Life becomes a lot simpler if we just use the global
nvme_subsystems_lock to protect this list.  Given that it is only
accessed during controller probing and removal that isn't a scalability
problem either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
This commit is contained in:
Christoph Hellwig 2019-05-08 09:48:27 +02:00
parent 521cfb8e5a
commit 32fd90c407
1 changed files with 14 additions and 18 deletions
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32
drivers/nvme/host/core.c
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@ -2346,13 +2346,13 @@ static int nvme_active_ctrls(struct nvme_subsystem *subsys)
int count = 0;
struct nvme_ctrl *ctrl;
mutex_lock(&subsys->lock);
lockdep_assert_held(&nvme_subsystems_lock);
list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
if (ctrl->state != NVME_CTRL_DELETING &&
ctrl->state != NVME_CTRL_DEAD)
count++;
}
mutex_unlock(&subsys->lock);
return count;
}
@ -2394,6 +2394,9 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
mutex_lock(&nvme_subsystems_lock);
found = __nvme_find_get_subsystem(subsys->subnqn);
if (found) {
__nvme_release_subsystem(subsys);
subsys = found;
/*
* Verify that the subsystem actually supports multiple
* controllers, else bail out.
@ -2402,14 +2405,10 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
nvme_active_ctrls(found) && !(id->cmic & (1 << 1))) {
dev_err(ctrl->device,
"ignoring ctrl due to duplicate subnqn (%s).\n",
found->subnqn);
nvme_put_subsystem(found);
subsys->subnqn);
ret = -EINVAL;
goto out_unlock;
goto out_put_subsystem;
}
__nvme_release_subsystem(subsys);
subsys = found;
} else {
ret = device_add(&subsys->dev);
if (ret) {
@ -2421,23 +2420,20 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
list_add_tail(&subsys->entry, &nvme_subsystems);
}
ctrl->subsys = subsys;
mutex_unlock(&nvme_subsystems_lock);
if (sysfs_create_link(&subsys->dev.kobj, &ctrl->device->kobj,
dev_name(ctrl->device))) {
dev_err(ctrl->device,
"failed to create sysfs link from subsystem.\n");
/* the transport driver will eventually put the subsystem */
return -EINVAL;
goto out_put_subsystem;
}
mutex_lock(&subsys->lock);
ctrl->subsys = subsys;
list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
mutex_unlock(&subsys->lock);
mutex_unlock(&nvme_subsystems_lock);
return 0;
out_put_subsystem:
nvme_put_subsystem(subsys);
out_unlock:
mutex_unlock(&nvme_subsystems_lock);
put_device(&subsys->dev);
@ -3694,10 +3690,10 @@ static void nvme_free_ctrl(struct device *dev)
__free_page(ctrl->discard_page);
if (subsys) {
mutex_lock(&subsys->lock);
mutex_lock(&nvme_subsystems_lock);
list_del(&ctrl->subsys_entry);
mutex_unlock(&subsys->lock);
sysfs_remove_link(&subsys->dev.kobj, dev_name(ctrl->device));
mutex_unlock(&nvme_subsystems_lock);
}
ctrl->ops->free_ctrl(ctrl);