[PATCH 2/3] nvme: move get/put ctrl into dev open/release

[Chaitanya Kulkarni]

Introduce nvme_dev_release ctrl file release callback and move ctrl get
and put operations from target passthru into host core in ctrl open and
release file operations respectively. This is needed to atomically
get/put ctrl and get/put ctrl module refcount without using any locks.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
---
 drivers/nvme/host/core.c       | 12 +++++++++++-
 drivers/nvme/target/passthru.c |  7 ++-----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index fa7c0def9184..a1707afcb710 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3262,6 +3262,16 @@ static int nvme_dev_open(struct inode *inode, struct file *file)
 	}
 
 	file->private_data = ctrl;
+	nvme_get_ctrl(ctrl);
+	return 0;
+}
+
+static int nvme_dev_release(struct inode *inode, struct file *file)
+{
+	struct nvme_ctrl *ctrl =
+		container_of(inode->i_cdev, struct nvme_ctrl, cdev);
+
+	nvme_put_ctrl(ctrl);
 	return 0;
 }
 
@@ -3327,6 +3337,7 @@ static long nvme_dev_ioctl(struct file *file, unsigned int cmd,
 static const struct file_operations nvme_dev_fops = {
 	.owner		= THIS_MODULE,
 	.open		= nvme_dev_open,
+	.release	= nvme_dev_release,
 	.unlocked_ioctl	= nvme_dev_ioctl,
 	.compat_ioctl	= compat_ptr_ioctl,
 };
@@ -4651,7 +4662,6 @@ struct nvme_ctrl *nvme_ctrl_get_by_file(struct file *f)
 	}
 
 	ctrl = f->private_data;
-	nvme_get_ctrl(ctrl);
 
 out_close:
 	return ctrl;
diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
index 14a842408035..9cd8fd2ddc72 100644
--- a/drivers/nvme/target/passthru.c
+++ b/drivers/nvme/target/passthru.c
@@ -507,11 +507,11 @@ int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys)
 			 subsys, GFP_KERNEL);
 	if (xa_is_err(old)) {
 		ret = xa_err(old);
-		goto out_put_ctrl;
+		goto out_put_file;
 	}
 
 	if (old)
-		goto out_put_ctrl;
+		goto out_put_file;
 
 	subsys->passthru_ctrl = ctrl;
 	subsys->ver = ctrl->vs;
@@ -526,8 +526,6 @@ int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys)
 	mutex_unlock(&subsys->lock);
 	return 0;
 
-out_put_ctrl:
-	nvme_put_ctrl(ctrl);
 out_put_file:
 	filp_close(subsys->passthru_ctrl_file, NULL);
 out_unlock:
@@ -540,7 +538,6 @@ static void __nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys)
 	if (subsys->passthru_ctrl) {
 		xa_erase(&passthru_subsystems, subsys->passthru_ctrl->cntlid);
 		filp_close(subsys->passthru_ctrl_file, NULL);
-		nvme_put_ctrl(subsys->passthru_ctrl);
 	}
 	subsys->passthru_ctrl = NULL;
 	subsys->ver = NVMET_DEFAULT_VS;
-- 
2.22.1