[PATCH v2 06/13] nvme-multipath: add nvme_mpath_cdev_ioctl()

[John Garry <john.g.garry@oracle.com>]

Add nvme_mpath_cdev_ioctl(), which does the same as
nvme_ns_head_chr_ioctl()

Also add nvme_mpath_ioctl_begin() and nvme_mpath_ioctl_finish() - they are
special handling for how the SRCU read lock needs to be dropped for the
controller command IOCTL handling. In this, nvme_mpath_ioctl_begin() takes
a reference to the controller, and then mpath_chr_ioctl() will drop the
SRCU read lock before calling nvme_mpath_cdev_ioctl() and finally the
controller reference is dropped in nvme_mpath_ioctl_finish().

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
 drivers/nvme/host/ioctl.c     | 37 +++++++++++++++++++++++++++++++----
 drivers/nvme/host/multipath.c |  3 +++
 drivers/nvme/host/nvme.h      |  6 ++++++
 3 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 8844bbd395159..ee99b8dbcdfff 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -624,11 +624,9 @@ int nvme_ioctl(struct block_device *bdev, blk_mode_t mode,
 	return nvme_ns_ioctl(ns, cmd, argp, flags, open_for_write);
 }
 
-long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+static long _nvme_ns_chr_ioctl(struct nvme_ns *ns, unsigned int cmd,
+				unsigned long arg, bool open_for_write)
 {
-	struct nvme_ns *ns =
-		container_of(file_inode(file)->i_cdev, struct nvme_ns, cdev);
-	bool open_for_write = file->f_mode & FMODE_WRITE;
 	void __user *argp = (void __user *)arg;
 
 	if (is_ctrl_ioctl(cmd))
@@ -636,6 +634,14 @@ long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	return nvme_ns_ioctl(ns, cmd, argp, 0, open_for_write);
 }
 
+long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct nvme_ns *ns =
+		container_of(file_inode(file)->i_cdev, struct nvme_ns, cdev);
+
+	return _nvme_ns_chr_ioctl(ns, cmd, arg, file->f_mode & FMODE_WRITE);
+}
+
 static int nvme_uring_cmd_checks(unsigned int issue_flags)
 {
 
@@ -690,6 +696,29 @@ int nvme_ns_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd,
 	return 0;
 }
 #ifdef CONFIG_NVME_MULTIPATH
+long nvme_mpath_cdev_ioctl(struct mpath_device *mpath_device, unsigned int cmd,
+					unsigned long arg, bool open_for_write)
+{
+	return _nvme_ns_chr_ioctl(nvme_mpath_to_ns(mpath_device), cmd,
+			arg, open_for_write);
+}
+
+void nvme_mpath_ioctl_begin(struct mpath_device *mpath_device,
+		unsigned int cmd, void **data)
+{
+	struct nvme_ctrl *ctrl = nvme_mpath_to_ns(mpath_device)->ctrl;
+
+	if (is_ctrl_ioctl(cmd)) {
+		nvme_get_ctrl(ctrl);
+		*data = ctrl;
+	}
+}
+
+void nvme_mpath_ioctl_finish(void *opaque)
+{
+	nvme_put_ctrl(opaque);
+}
+
 static int nvme_ns_head_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
 		void __user *argp, struct nvme_ns_head *head, int srcu_idx,
 		bool open_for_write)
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index d9ab52a29ea8b..5e49cd716f859 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -1445,4 +1445,7 @@ static const struct mpath_head_template mpdt = {
 	.del_cdev = nvme_mpath_del_cdev,
 	.is_disabled = nvme_mpath_is_disabled,
 	.is_optimized = nvme_mpath_is_optimized,
+	.cdev_ioctl = nvme_mpath_cdev_ioctl,
+	.ioctl_begin = nvme_mpath_ioctl_begin,
+	.ioctl_finish = nvme_mpath_ioctl_finish,
 };
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index f3026da0f39d9..1ec45cce05c9c 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -1053,6 +1053,12 @@ void nvme_mpath_remove_disk(struct nvme_ns_head *head);
 void nvme_mpath_start_request(struct request *rq);
 void nvme_mpath_end_request(struct request *rq);
 
+long nvme_mpath_cdev_ioctl(struct mpath_device *mpath_device, unsigned int cmd,
+			unsigned long arg, bool open_for_write);
+void nvme_mpath_ioctl_begin(struct mpath_device *mpath_device,
+			unsigned int cmd, void **opaque);
+void nvme_mpath_ioctl_finish(void *opaque);
+
 static inline void nvme_trace_bio_complete(struct request *req)
 {
 	struct nvme_ns *ns = req->q->queuedata;
-- 
2.43.5