[v9,01/12] nvme-core: introduce nvme_ctrl_get_by_path()
diff mbox series

Message ID 20191009192530.13079-2-logang@deltatee.com
State New
Headers show
Series
  • nvmet: add target passthru commands support
Related show

Commit Message

Logan Gunthorpe Oct. 9, 2019, 7:25 p.m. UTC
nvme_ctrl_get_by_path() is analagous to blkdev_get_by_path() except it
gets a struct nvme_ctrl from the path to its char dev (/dev/nvme0).
It makes use of filp_open() to open the file and uses the private
data to obtain a pointer to the struct nvme_ctrl. If the fops of the
file do not match, -EINVAL is returned.

The purpose of this function is to support NVMe-OF target passthru.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/core.c | 24 ++++++++++++++++++++++++
 drivers/nvme/host/nvme.h |  2 ++
 2 files changed, 26 insertions(+)

Comments

Keith Busch Oct. 9, 2019, 10:13 p.m. UTC | #1
On Wed, Oct 09, 2019 at 01:25:18PM -0600, Logan Gunthorpe wrote:
> nvme_ctrl_get_by_path() is analagous to blkdev_get_by_path() except it
> gets a struct nvme_ctrl from the path to its char dev (/dev/nvme0).
> It makes use of filp_open() to open the file and uses the private
> data to obtain a pointer to the struct nvme_ctrl. If the fops of the
> file do not match, -EINVAL is returned.
> 
> The purpose of this function is to support NVMe-OF target passthru.
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

Looks fine.

Reviewed-by: Keith Busch <kbusch@kernel.org>
Christoph Hellwig Oct. 10, 2019, 11:37 a.m. UTC | #2
> +struct nvme_ctrl *nvme_ctrl_get_by_path(const char *path)
> +{
> +	struct nvme_ctrl *ctrl;
> +	struct file *f;
> +
> +	f = filp_open(path, O_RDWR, 0);
> +	if (IS_ERR(f))
> +		return ERR_CAST(f);
> +
> +	if (f->f_op != &nvme_dev_fops) {
> +		ctrl = ERR_PTR(-EINVAL);
> +		goto out_close;
> +	}
> +
> +	ctrl = f->private_data;
> +	nvme_get_ctrl(ctrl);
> +
> +out_close:
> +	filp_close(f, NULL);
> +
> +	return ctrl;

No need for the empty line here.  Also can you make sure this new
code (and all the new exports) are only enabled if
CONFIG_NVME_TARGET_PASSTHRU is set.  Preferably by having a little
block at the end of this file with this function and the extra
exports with a big fat comment that they are only for nvmet-passthrough.

Patch
diff mbox series

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index fd7dea36c3b6..30f9d91e25e3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2950,6 +2950,30 @@  static const struct file_operations nvme_dev_fops = {
 	.compat_ioctl	= nvme_dev_ioctl,
 };
 
+struct nvme_ctrl *nvme_ctrl_get_by_path(const char *path)
+{
+	struct nvme_ctrl *ctrl;
+	struct file *f;
+
+	f = filp_open(path, O_RDWR, 0);
+	if (IS_ERR(f))
+		return ERR_CAST(f);
+
+	if (f->f_op != &nvme_dev_fops) {
+		ctrl = ERR_PTR(-EINVAL);
+		goto out_close;
+	}
+
+	ctrl = f->private_data;
+	nvme_get_ctrl(ctrl);
+
+out_close:
+	filp_close(f, NULL);
+
+	return ctrl;
+}
+EXPORT_SYMBOL_GPL(nvme_ctrl_get_by_path);
+
 static ssize_t nvme_sysfs_reset(struct device *dev,
 				struct device_attribute *attr, const char *buf,
 				size_t count)
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 38a83ef5bcd3..f83f990e409d 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -507,6 +507,8 @@  int nvme_get_log(struct nvme_ctrl *ctrl, u32 nsid, u8 log_page, u8 lsp,
 extern const struct attribute_group *nvme_ns_id_attr_groups[];
 extern const struct block_device_operations nvme_ns_head_ops;
 
+struct nvme_ctrl *nvme_ctrl_get_by_path(const char *path);
+
 #ifdef CONFIG_NVME_MULTIPATH
 static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
 {