[PATCH 13/13] nvme: introduce generic per-namespace chardev
Christoph Hellwig
hch at lst.de
Thu Apr 8 13:08:42 BST 2021
From: Minwoo Im <minwoo.im.dev at gmail.com>
Userspace has not been allowed to I/O to device that's failed to
be initialized. This patch introduces generic per-namespace character
device to allow userspace to I/O regardless the block device is there or
not.
The chardev naming convention will similar to the existing blkdev naming,
using a ng prefix instead of nvme, i.e.
- /dev/ngXnY
It also supports multipath which means it will not expose chardev for the
hidden namespace blkdevs (e.g., nvmeXcYnZ). If /dev/ngXnY is created for
a ns_head, then I/O request will be routed to a specific controller
selected by the iopolicy of the subsystem.
Signed-off-by: Minwoo Im <minwoo.im.dev at gmail.com>
Signed-off-by: Javier González <javier.gonz at samsung.com>
[hch: rebased on top of the ioctl cleanups, split the ns_head and ns
implementations]
Signed-off-by: Christoph Hellwig <hch at lst.de>
---
drivers/nvme/host/core.c | 81 +++++++++++++++++++++++++++++++++++
drivers/nvme/host/ioctl.c | 17 ++++++++
drivers/nvme/host/multipath.c | 51 ++++++++++++++++++++--
drivers/nvme/host/nvme.h | 12 ++++++
4 files changed, 158 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index eba676b260b820..fa8bddc31442a3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -89,6 +89,10 @@ static dev_t nvme_ctrl_base_chr_devt;
static struct class *nvme_class;
static struct class *nvme_subsys_class;
+static DEFINE_IDA(nvme_ns_chr_minor_ida);
+static dev_t nvme_ns_chr_devt;
+static struct class *nvme_ns_chr_class;
+
static void nvme_put_subsystem(struct nvme_subsystem *subsys);
static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
unsigned nsid);
@@ -3424,6 +3428,60 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys,
return 0;
}
+int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
+ const struct file_operations *fops, struct module *owner)
+{
+ int minor, ret;
+
+ minor = ida_simple_get(&nvme_ns_chr_minor_ida, 0, 0, GFP_KERNEL);
+ if (minor < 0)
+ return minor;
+ cdev_device->devt = MKDEV(MAJOR(nvme_ns_chr_devt), minor);
+ cdev_device->class = nvme_ns_chr_class;
+ device_initialize(cdev_device);
+ cdev_init(cdev, fops);
+ cdev->owner = owner;
+ ret = cdev_device_add(cdev, cdev_device);
+ if (ret)
+ ida_simple_remove(&nvme_ns_chr_minor_ida, minor);
+ return ret;
+}
+
+static int nvme_ns_chr_open(struct inode *inode, struct file *file)
+{
+ return nvme_ns_open(container_of(inode->i_cdev, struct nvme_ns, cdev));
+}
+
+static int nvme_ns_chr_release(struct inode *inode, struct file *file)
+{
+ nvme_ns_release(container_of(inode->i_cdev, struct nvme_ns, cdev));
+ return 0;
+}
+
+static const struct file_operations nvme_ns_chr_fops = {
+ .owner = THIS_MODULE,
+ .open = nvme_ns_chr_open,
+ .release = nvme_ns_chr_release,
+ .unlocked_ioctl = nvme_ns_chr_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+};
+
+static int nvme_add_ns_cdev(struct nvme_ns *ns)
+{
+ int ret;
+
+ ns->cdev_device.parent = ns->ctrl->device;
+ ret = dev_set_name(&ns->cdev_device, "ng%dn%d",
+ ns->ctrl->instance, ns->head->instance);
+ if (ret)
+ return ret;
+ ret = nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
+ ns->ctrl->ops->module);
+ if (ret)
+ kfree_const(ns->cdev_device.kobj.name);
+ return ret;
+}
+
static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
unsigned nsid, struct nvme_ns_ids *ids)
{
@@ -3625,6 +3683,8 @@ 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);
+ if (!nvme_ns_head_multipath(ns->head))
+ nvme_add_ns_cdev(ns);
nvme_mpath_add_disk(ns, id);
nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
@@ -3669,6 +3729,8 @@ static void nvme_ns_remove(struct nvme_ns *ns)
synchronize_srcu(&ns->head->srcu); /* wait for concurrent submissions */
if (ns->disk->flags & GENHD_FL_UP) {
+ if (!nvme_ns_head_multipath(ns->head))
+ cdev_device_del(&ns->cdev, &ns->cdev_device);
del_gendisk(ns->disk);
blk_cleanup_queue(ns->queue);
if (blk_get_integrity(ns->disk))
@@ -4459,8 +4521,24 @@ static int __init nvme_core_init(void)
result = PTR_ERR(nvme_subsys_class);
goto destroy_class;
}
+
+ result = alloc_chrdev_region(&nvme_ns_chr_devt, 0, NVME_MINORS,
+ "nvme-generic");
+ if (result < 0)
+ goto destroy_subsys_class;
+
+ nvme_ns_chr_class = class_create(THIS_MODULE, "nvme-generic");
+ if (IS_ERR(nvme_ns_chr_class)) {
+ result = PTR_ERR(nvme_ns_chr_class);
+ goto unregister_generic_ns;
+ }
+
return 0;
+unregister_generic_ns:
+ unregister_chrdev_region(nvme_ns_chr_devt, NVME_MINORS);
+destroy_subsys_class:
+ class_destroy(nvme_subsys_class);
destroy_class:
class_destroy(nvme_class);
unregister_chrdev:
@@ -4477,12 +4555,15 @@ static int __init nvme_core_init(void)
static void __exit nvme_core_exit(void)
{
+ class_destroy(nvme_ns_chr_class);
class_destroy(nvme_subsys_class);
class_destroy(nvme_class);
+ unregister_chrdev_region(nvme_ns_chr_devt, NVME_MINORS);
unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
destroy_workqueue(nvme_delete_wq);
destroy_workqueue(nvme_reset_wq);
destroy_workqueue(nvme_wq);
+ ida_destroy(&nvme_ns_chr_minor_ida);
ida_destroy(&nvme_instance_ida);
}
diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 001faf31fb944f..304dc66bcebf22 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -357,6 +357,14 @@ int nvme_ioctl(struct block_device *bdev, fmode_t mode,
return nvme_ns_ioctl(ns, cmd, argp);
}
+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_ioctl(ns, cmd, (void __user *)arg);
+}
+
#ifdef CONFIG_NVME_MULTIPATH
static int nvme_ns_head_ctrl_ioctl(struct nvme_ns_head *head,
unsigned int cmd, void __user *argp)
@@ -393,6 +401,15 @@ int nvme_ns_head_ioctl(struct block_device *bdev, fmode_t mode,
return nvme_ns_head_ctrl_ioctl(head, cmd, (void __user *)arg);
return nvme_ns_head_ns_ioctl(head, cmd, (void __user *)arg);
}
+
+long nvme_ns_head_chr_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct cdev *cdev = file_inode(file)->i_cdev;
+ struct nvme_ns_head *head = container_of(cdev, struct nvme_ns_head, cdev);
+
+ return nvme_ns_head_ns_ioctl(head, cmd, (void __user *)arg);
+}
#endif /* CONFIG_NVME_MULTIPATH */
static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp)
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 2bbc1685799d44..40c6cc989e373a 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -357,6 +357,48 @@ const struct block_device_operations nvme_ns_head_ops = {
.pr_ops = &nvme_pr_ops,
};
+static inline struct nvme_ns_head *cdev_to_ns_head(struct cdev *cdev)
+{
+ return container_of(cdev, struct nvme_ns_head, cdev);
+}
+
+static int nvme_ns_head_chr_open(struct inode *inode, struct file *file)
+{
+ if (!nvme_tryget_ns_head(cdev_to_ns_head(inode->i_cdev)))
+ return -ENXIO;
+ return 0;
+}
+
+static int nvme_ns_head_chr_release(struct inode *inode, struct file *file)
+{
+ nvme_put_ns_head(cdev_to_ns_head(inode->i_cdev));
+ return 0;
+}
+
+static const struct file_operations nvme_ns_head_chr_fops = {
+ .owner = THIS_MODULE,
+ .open = nvme_ns_head_chr_open,
+ .release = nvme_ns_head_chr_release,
+ .unlocked_ioctl = nvme_ns_head_chr_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+};
+
+static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
+{
+ int ret;
+
+ head->cdev_device.parent = &head->subsys->dev;
+ ret = dev_set_name(&head->cdev_device, "ng%dn%d",
+ head->subsys->instance, head->instance);
+ if (ret)
+ return ret;
+ ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
+ &nvme_ns_head_chr_fops, THIS_MODULE);
+ if (ret)
+ kfree_const(head->cdev_device.kobj.name);
+ return ret;
+}
+
static void nvme_requeue_work(struct work_struct *work)
{
struct nvme_ns_head *head =
@@ -435,9 +477,11 @@ static void nvme_mpath_set_live(struct nvme_ns *ns)
if (!head->disk)
return;
- if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags))
+ if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
device_add_disk(&head->subsys->dev, head->disk,
nvme_ns_id_attr_groups);
+ nvme_add_ns_head_cdev(head);
+ }
mutex_lock(&head->lock);
if (nvme_path_is_optimized(ns)) {
@@ -714,8 +758,10 @@ void nvme_mpath_remove_disk(struct nvme_ns_head *head)
{
if (!head->disk)
return;
- if (head->disk->flags & GENHD_FL_UP)
+ if (head->disk->flags & GENHD_FL_UP) {
+ cdev_device_del(&head->cdev, &head->cdev_device);
del_gendisk(head->disk);
+ }
blk_set_queue_dying(head->disk->queue);
/* make sure all pending bios are cleaned up */
kblockd_schedule_work(&head->requeue_work);
@@ -785,4 +831,3 @@ void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
kfree(ctrl->ana_log_buf);
ctrl->ana_log_buf = NULL;
}
-
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index c6102ce83bb405..d34e29d76abb54 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -413,6 +413,10 @@ struct nvme_ns_head {
bool shared;
int instance;
struct nvme_effects_log *effects;
+
+ struct cdev cdev;
+ struct device cdev_device;
+
struct gendisk *disk;
#ifdef CONFIG_NVME_MULTIPATH
struct bio_list requeue_list;
@@ -465,6 +469,9 @@ struct nvme_ns {
#define NVME_NS_ANA_PENDING 2
#define NVME_NS_FORCE_RO 3
+ struct cdev cdev;
+ struct device cdev_device;
+
struct nvme_fault_inject fault_inject;
};
@@ -659,10 +666,15 @@ void nvme_put_ns_from_disk(struct nvme_ns_head *head, int idx);
bool nvme_tryget_ns_head(struct nvme_ns_head *head);
void nvme_put_ns_head(struct nvme_ns_head *head);
struct nvme_ctrl *nvme_find_get_live_ctrl(struct nvme_subsystem *subsys);
+int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
+ const struct file_operations *fops, struct module *owner);
int nvme_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg);
+long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
int nvme_ns_head_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg);
+long nvme_ns_head_chr_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg);
long nvme_dev_ioctl(struct file *file, unsigned int cmd,
unsigned long arg);
int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo);
--
2.30.1
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