From: Javier González <javier.gonz@xxxxxxxxxxx>
Create a char device per NVMe namespace. This char device is always
initialized, independently of whether the features implemented by the
device are supported by the kernel. User-space can therefore always
issue IOCTLs to the NVMe driver using the char device.
The char device is presented as /dev/generic-nvmeXcYnZ. This naming
scheme follows the convention of the hidden device (nvmeXcYnZ). Support
for multipath will follow.
Christoph, Keith: Is this going in the right direction?
Keith: Regarding nvme-cli support, what do you think about reporting the
char device as existing block devices? If this is OK with you, I will
submit patches for the filters.
Changes since V2:
- Apply a number of naming and code structure improvements (from
Christoph)
- Use i_cdev to pull struct nvme_ns in the ioctl path instead of
populating file->private_data (from Christoph)
- Change char device and sysfs entries to /dev/generic-nvmeXcYnZ to
follow the hidden device naming scheme (from Christoph and Keith)
Changes since V1:
- Remove patches 1-3 which are already picked up by Christoph
- Change the char device and sysfs entries to nvmeXnYc / c signals
char device
- Address Minwoo's comments on inline functions and style
Signed-off-by: Javier González <javier.gonz@xxxxxxxxxxx>
---
drivers/nvme/host/core.c | 142 ++++++++++++++++++++++++++++++++++-----
drivers/nvme/host/nvme.h | 8 +++
2 files changed, 134 insertions(+), 16 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 99f91efe3824..006ac8ee9c7c 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -86,7 +86,9 @@ static DEFINE_MUTEX(nvme_subsystems_lock);
static DEFINE_IDA(nvme_instance_ida);
static dev_t nvme_ctrl_base_chr_devt;
+static dev_t nvme_ns_base_chr_devt;
static struct class *nvme_class;
+static struct class *nvme_ns_class;
static struct class *nvme_subsys_class;
static void nvme_put_subsystem(struct nvme_subsystem *subsys);
@@ -538,6 +540,7 @@ static void nvme_free_ns(struct kref *kref)
if (ns->ndev)
nvme_nvm_unregister(ns);
+ cdev_device_del(&ns->cdev, &ns->cdev_device);
put_disk(ns->disk);
nvme_put_ns_head(ns->head);
nvme_put_ctrl(ns->ctrl);
@@ -1738,15 +1741,15 @@ static int nvme_handle_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
return ret;
}
-static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
- unsigned int cmd, unsigned long arg)
+static int nvme_disk_ioctl(struct gendisk *disk, unsigned int cmd,
+ unsigned long arg)
{
struct nvme_ns_head *head = NULL;
void __user *argp = (void __user *)arg;
struct nvme_ns *ns;
int srcu_idx, ret;
- ns = nvme_get_ns_from_disk(bdev->bd_disk, &head, &srcu_idx);
+ ns = nvme_get_ns_from_disk(disk, &head, &srcu_idx);
if (unlikely(!ns))
return -EWOULDBLOCK;
@@ -1783,6 +1786,12 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
return ret;
}
+static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ return nvme_disk_ioctl(bdev->bd_disk, cmd, arg);
+}
+
#ifdef CONFIG_COMPAT
struct nvme_user_io32 {
__u8 opcode;
@@ -1824,10 +1833,8 @@ static int nvme_compat_ioctl(struct block_device *bdev, fmode_t mode,
#define nvme_compat_ioctl NULL
#endif /* CONFIG_COMPAT */
-static int nvme_open(struct block_device *bdev, fmode_t mode)
+static int nvme_ns_open(struct nvme_ns *ns)
{
- struct nvme_ns *ns = bdev->bd_disk->private_data;
-
#ifdef CONFIG_NVME_MULTIPATH
/* should never be called due to GENHD_FL_HIDDEN */
if (WARN_ON_ONCE(ns->head->disk))
@@ -1846,14 +1853,22 @@ static int nvme_open(struct block_device *bdev, fmode_t mode)
return -ENXIO;
}
-static void nvme_release(struct gendisk *disk, fmode_t mode)
+static void nvme_ns_release(struct nvme_ns *ns)
{
- struct nvme_ns *ns = disk->private_data;
-
module_put(ns->ctrl->ops->module);
nvme_put_ns(ns);
}
+static int nvme_open(struct block_device *bdev, fmode_t mode)
+{
+ return nvme_ns_open(bdev->bd_disk->private_data);
+}
+
+static void nvme_release(struct gendisk *disk, fmode_t mode)
+{
+ nvme_ns_release(disk->private_data);
+}
+
static int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
/* some standard values */
@@ -2209,6 +2224,13 @@ static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_id_ns *id)
return 0;
out_unfreeze:
+ /*
+ * When the device does not support any of the features required by the
+ * kernel (or viceversa), hide the block device. We can still rely on
+ * the namespace char device for submitting IOCTLs
+ */
+ ns->disk->flags |= GENHD_FL_HIDDEN;
+
blk_mq_unfreeze_queue(ns->disk->queue);
return ret;
}
@@ -2346,6 +2368,38 @@ static const struct block_device_operations nvme_bdev_ops = {
.pr_ops = &nvme_pr_ops,
};
+static int nvme_cdev_open(struct inode *inode, struct file *file)
+{
+ struct nvme_ns *ns = container_of(inode->i_cdev, struct nvme_ns, cdev);
+
+ return nvme_ns_open(ns);
+}
+
+static int nvme_cdev_release(struct inode *inode, struct file *file)
+{
+ struct nvme_ns *ns = container_of(inode->i_cdev, struct nvme_ns, cdev);
+
+ nvme_ns_release(ns);
+ return 0;
+}
+
+static long nvme_cdev_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct nvme_ns *ns = container_of(file->f_inode->i_cdev,
+ struct nvme_ns, cdev);
+
+ return nvme_disk_ioctl(ns->disk, cmd, arg);
+}
+
+static const struct file_operations nvme_cdev_fops = {
+ .owner = THIS_MODULE,
+ .open = nvme_cdev_open,
+ .release = nvme_cdev_release,
+ .unlocked_ioctl = nvme_cdev_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+};
+
#ifdef CONFIG_NVME_MULTIPATH
static int nvme_ns_head_open(struct block_device *bdev, fmode_t mode)
{
@@ -3343,6 +3397,9 @@ static inline struct nvme_ns_head *dev_to_ns_head(struct device *dev)
{
struct gendisk *disk = dev_to_disk(dev);
+ if (dev->class == nvme_ns_class)
+ return nvme_get_ns_from_cdev(dev)->head;
+
if (disk->fops == &nvme_bdev_ops)
return nvme_get_ns_from_dev(dev)->head;
else
@@ -3474,6 +3531,11 @@ const struct attribute_group *nvme_ns_id_attr_groups[] = {
NULL,
};
+const struct attribute_group *nvme_ns_char_id_attr_groups[] = {
+ &nvme_ns_id_attr_group,
+ NULL,
+};
+
#define nvme_show_str_function(field) \
static ssize_t field##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
@@ -3866,6 +3928,36 @@ struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid)
}
EXPORT_SYMBOL_NS_GPL(nvme_find_get_ns, NVME_TARGET_PASSTHRU);
+static int nvme_alloc_chardev_ns(struct nvme_ctrl *ctrl, struct nvme_ns *ns)
+{
+ char cdisk_name[DISK_NAME_LEN];
+ int ret;
+
+ device_initialize(&ns->cdev_device);
+ ns->cdev_device.devt = MKDEV(MAJOR(nvme_ns_base_chr_devt),
+ ns->head->instance);
+ ns->cdev_device.class = nvme_ns_class;
+ ns->cdev_device.parent = ctrl->device;
+ ns->cdev_device.groups = nvme_ns_char_id_attr_groups;
+ dev_set_drvdata(&ns->cdev_device, ns);
+
+ sprintf(cdisk_name, "nvme-generic-%dc%dn%d", ctrl->subsys->instance,
+ ctrl->instance, ns->head->instance);
+
+ ret = dev_set_name(&ns->cdev_device, "%s", cdisk_name);
+ if (ret)
+ return ret;
+
+ cdev_init(&ns->cdev, &nvme_cdev_fops);
+ ns->cdev.owner = ctrl->ops->module;
+
+ ret = cdev_device_add(&ns->cdev, &ns->cdev_device);
+ if (ret)
+ kfree_const(ns->cdev_device.kobj.name);
+
+ return ret;
+}
+
static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
struct nvme_ns_ids *ids)
{
@@ -3912,8 +4004,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
memcpy(disk->disk_name, disk_name, DISK_NAME_LEN);
ns->disk = disk;
- if (nvme_update_ns_info(ns, id))
- goto out_put_disk;
+ nvme_update_ns_info(ns, id);
if ((ctrl->quirks & NVME_QUIRK_LIGHTNVM) && id->vs[0] == 0x1) {
if (nvme_nvm_register(ns, disk_name, node)) {
@@ -3929,9 +4020,12 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
nvme_get_ctrl(ctrl);
device_add_disk(ctrl->device, ns->disk, nvme_ns_id_attr_groups);
-
nvme_mpath_add_disk(ns, id);
nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
+
+ if (nvme_alloc_chardev_ns(ctrl, ns))
+ goto out_put_disk;
+
kfree(id);
return;
@@ -4733,23 +4827,38 @@ static int __init nvme_core_init(void)
if (result < 0)
goto destroy_delete_wq;
+ result = alloc_chrdev_region(&nvme_ns_base_chr_devt, 0,
+ NVME_MINORS, "nvmec");
+ if (result < 0)
+ goto unregister_dev_chrdev;
+
nvme_class = class_create(THIS_MODULE, "nvme");
if (IS_ERR(nvme_class)) {
result = PTR_ERR(nvme_class);
- goto unregister_chrdev;
+ goto unregister_ns_chrdev;
}
nvme_class->dev_uevent = nvme_class_uevent;
+ nvme_ns_class = class_create(THIS_MODULE, "nvme-ns");
+ if (IS_ERR(nvme_ns_class)) {
+ result = PTR_ERR(nvme_ns_class);
+ goto destroy_dev_class;
+ }
+
nvme_subsys_class = class_create(THIS_MODULE, "nvme-subsystem");
if (IS_ERR(nvme_subsys_class)) {
result = PTR_ERR(nvme_subsys_class);
- goto destroy_class;
+ goto destroy_ns_class;
}
return 0;
-destroy_class:
+destroy_ns_class:
+ class_destroy(nvme_ns_class);
+destroy_dev_class:
class_destroy(nvme_class);
-unregister_chrdev:
+unregister_ns_chrdev:
+ unregister_chrdev_region(nvme_ns_base_chr_devt, NVME_MINORS);
+unregister_dev_chrdev:
unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
destroy_delete_wq:
destroy_workqueue(nvme_delete_wq);
@@ -4765,6 +4874,7 @@ static void __exit nvme_core_exit(void)
{
class_destroy(nvme_subsys_class);
class_destroy(nvme_class);
+ unregister_chrdev_region(nvme_ns_base_chr_devt, NVME_MINORS);
unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
destroy_workqueue(nvme_delete_wq);
destroy_workqueue(nvme_reset_wq);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index bfcedfa4b057..1dd99f207aee 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -439,6 +439,9 @@ struct nvme_ns {
struct kref kref;
struct nvme_ns_head *head;
+ struct device cdev_device; /* char device */
+ struct cdev cdev;
+
int lba_shift;
u16 ms;
u16 sgs;
@@ -818,6 +821,11 @@ static inline struct nvme_ns *nvme_get_ns_from_dev(struct device *dev)
return dev_to_disk(dev)->private_data;
}
+static inline struct nvme_ns *nvme_get_ns_from_cdev(struct device *dev)
+{
+ return dev_get_drvdata(dev);
+}
+
#ifdef CONFIG_NVME_HWMON
int nvme_hwmon_init(struct nvme_ctrl *ctrl);
#else
--
2.17.1
