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[5.186.124.214]) by smtp.gmail.com with ESMTPSA id k23sm1948451ejs.100.2020.12.16.10.18.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Dec 2020 10:18:32 -0800 (PST) From: javier@javigon.com X-Google-Original-From: javier.gonz@samsung.com To: linux-nvme@lists.infradead.org Cc: linux-block@vger.kernel.org, hch@lst.de, kbusch@kernel.org, sagi@grimberg.me, minwoo.im.dev@gmail.com, =?utf-8?q?Javier_Gonz=C3=A1lez?= Subject: [PATCH V4] nvme: enable char device per namespace Date: Wed, 16 Dec 2020 19:18:28 +0100 Message-Id: <20201216181828.21040-1-javier.gonz@samsung.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Javier González 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. Keith: Regarding nvme-cli support, should the generic handle show up in place such as 'nvme list'? If so, I can send a patch for the filters. Changes since V3 (merged patch from keith) - Use a dedicated ida for the generic handle - Do not abort namespace greation if the generic handle fails 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 --- drivers/nvme/host/core.c | 159 +++++++++++++++++++++++++++++++++++---- drivers/nvme/host/nvme.h | 9 +++ 2 files changed, 152 insertions(+), 16 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 99f91efe3824..d1ee462f41fa 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -86,7 +86,11 @@ static DEFINE_MUTEX(nvme_subsystems_lock); static DEFINE_IDA(nvme_instance_ida); static dev_t nvme_ctrl_base_chr_devt; + +static DEFINE_IDA(nvme_gen_minor_ida); +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); @@ -537,7 +541,10 @@ static void nvme_free_ns(struct kref *kref) if (ns->ndev) nvme_nvm_unregister(ns); + if (ns->minor) + ida_simple_remove(&nvme_gen_minor_ida, ns->minor - 1); + 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 +1745,15 @@ 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 +1790,12 @@ 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 +1837,8 @@ 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 +1857,22 @@ 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 +2228,13 @@ 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 +2372,38 @@ 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 +3401,9 @@ 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 +3535,11 @@ 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 +3932,47 @@ 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; + + ret = ida_simple_get(&nvme_gen_minor_ida, 0, 0, GFP_KERNEL); + if (ret < 0) + return ret; + + ns->minor = ret + 1; + device_initialize(&ns->cdev_device); + ns->cdev_device.devt = MKDEV(MAJOR(nvme_ns_base_chr_devt), ret); + 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) + goto put_ida; + + cdev_init(&ns->cdev, &nvme_cdev_fops); + ns->cdev.owner = ctrl->ops->module; + + ret = cdev_device_add(&ns->cdev, &ns->cdev_device); + if (ret) + goto free_kobj; + + return ret; + +free_kobj: + kfree_const(ns->cdev_device.kobj.name); +put_ida: + ida_simple_remove(&nvme_gen_minor_ida, ns->minor - 1); + ns->minor = 0; + return ret; +} + static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid, struct nvme_ns_ids *ids) { @@ -3912,8 +4019,7 @@ 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 +4035,14 @@ 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)) + dev_warn(ctrl->device, + "failed to create generic handle for nsid:%d\n", + nsid); + kfree(id); return; @@ -4733,23 +4844,38 @@ 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 +4891,7 @@ 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..1e52f7da82de 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -439,6 +439,10 @@ struct nvme_ns { struct kref kref; struct nvme_ns_head *head; + struct device cdev_device; /* char device */ + struct cdev cdev; + int minor; + int lba_shift; u16 ms; u16 sgs; @@ -818,6 +822,11 @@ 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