nvme: switch controller refcounting to use struct device

Instead of allocating a separate struct device for the character device
handle embedd it into struct nvme_ctrl and use it for the main controller
refcounting.  This removes double refcounting and gets us an automatic
reference for the character device operations.  We keep ctrl->device as a
pointer for now to avoid chaning printks all over, but in the future we
could look into message printing helpers that take a controller structure
similar to what other subsystems do.

Note the delete_ctrl operation always already has a reference (either
through sysfs due this change, or because every open file on the
/dev/nvme-fabrics node has a refernece) when it is entered now, so we
don't need to do the unless_zero variant there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 9f8ae15c9fe8e2dc9b7cd81164b5971440d4c1b7..3a97daa163f662c530e748af2a2a84deafa7d9e2 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1915,7 +1915,7 @@ static int nvme_dev_open(struct inode *inode, struct file *file)
                        ret = -EWOULDBLOCK;
                        break;
                }
-               if (!kref_get_unless_zero(&ctrl->kref))
+               if (!kobject_get_unless_zero(&ctrl->device->kobj))
                        break;
                file->private_data = ctrl;
                ret = 0;
@@ -2374,7 +2374,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
        list_add_tail(&ns->list, &ctrl->namespaces);
        mutex_unlock(&ctrl->namespaces_mutex);
 
-       kref_get(&ctrl->kref);
+       nvme_get_ctrl(ctrl);
 
        kfree(id);
 
@@ -2703,7 +2703,7 @@ EXPORT_SYMBOL_GPL(nvme_start_ctrl);
 
 void nvme_uninit_ctrl(struct nvme_ctrl *ctrl)
 {
-       device_destroy(nvme_class, MKDEV(nvme_char_major, ctrl->instance));
+       device_del(ctrl->device);
 
        spin_lock(&dev_list_lock);
        list_del(&ctrl->node);
@@ -2711,23 +2711,17 @@ void nvme_uninit_ctrl(struct nvme_ctrl *ctrl)
 }
 EXPORT_SYMBOL_GPL(nvme_uninit_ctrl);
 
-static void nvme_free_ctrl(struct kref *kref)
+static void nvme_free_ctrl(struct device *dev)
 {
-       struct nvme_ctrl *ctrl = container_of(kref, struct nvme_ctrl, kref);
+       struct nvme_ctrl *ctrl =
+               container_of(dev, struct nvme_ctrl, ctrl_device);
 
-       put_device(ctrl->device);
        ida_simple_remove(&nvme_instance_ida, ctrl->instance);
        ida_destroy(&ctrl->ns_ida);
 
        ctrl->ops->free_ctrl(ctrl);
 }
 
-void nvme_put_ctrl(struct nvme_ctrl *ctrl)
-{
-       kref_put(&ctrl->kref, nvme_free_ctrl);
-}
-EXPORT_SYMBOL_GPL(nvme_put_ctrl);
-
 /*
  * Initialize a NVMe controller structures.  This needs to be called during
  * earliest initialization so that we have the initialized structured around
@@ -2742,7 +2736,6 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
        spin_lock_init(&ctrl->lock);
        INIT_LIST_HEAD(&ctrl->namespaces);
        mutex_init(&ctrl->namespaces_mutex);
-       kref_init(&ctrl->kref);
        ctrl->dev = dev;
        ctrl->ops = ops;
        ctrl->quirks = quirks;
@@ -2755,15 +2748,21 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
                goto out;
        ctrl->instance = ret;
 
-       ctrl->device = device_create_with_groups(nvme_class, ctrl->dev,
-                               MKDEV(nvme_char_major, ctrl->instance),
-                               ctrl, nvme_dev_attr_groups,
-                               "nvme%d", ctrl->instance);
-       if (IS_ERR(ctrl->device)) {
-               ret = PTR_ERR(ctrl->device);
+       device_initialize(&ctrl->ctrl_device);
+       ctrl->device = &ctrl->ctrl_device;
+       ctrl->device->devt = MKDEV(nvme_char_major, ctrl->instance);
+       ctrl->device->class = nvme_class;
+       ctrl->device->parent = ctrl->dev;
+       ctrl->device->groups = nvme_dev_attr_groups;
+       ctrl->device->release = nvme_free_ctrl;
+       dev_set_drvdata(ctrl->device, ctrl);
+       ret = dev_set_name(ctrl->device, "nvme%d", ctrl->instance);
+       if (ret)
                goto out_release_instance;
-       }
-       get_device(ctrl->device);
+       ret = device_add(ctrl->device);
+       if (ret)
+               goto out_free_name;
+
        ida_init(&ctrl->ns_ida);
 
        spin_lock(&dev_list_lock);
@@ -2779,6 +2778,8 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
                min(default_ps_max_latency_us, (unsigned long)S32_MAX));
 
        return 0;
+out_free_name:
+       kfree_const(dev->kobj.name);
 out_release_instance:
        ida_simple_remove(&nvme_instance_ida, ctrl->instance);
 out:

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index c6c903f1b172a429b2808d4da08c33e307124d99..aa9aec6923bb75b8f2ab424bcae0919c494bccec 100644 (file)
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -2692,14 +2692,10 @@ nvme_fc_del_nvme_ctrl(struct nvme_ctrl *nctrl)
        struct nvme_fc_ctrl *ctrl = to_fc_ctrl(nctrl);
        int ret;
 
-       if (!kref_get_unless_zero(&ctrl->ctrl.kref))
-               return -EBUSY;
-
+       nvme_get_ctrl(&ctrl->ctrl);
        ret = __nvme_fc_del_ctrl(ctrl);
-
        if (!ret)
                flush_workqueue(nvme_wq);
-
        nvme_put_ctrl(&ctrl->ctrl);
 
        return ret;
@@ -2918,7 +2914,7 @@ nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
                return ERR_PTR(ret);
        }
 
-       kref_get(&ctrl->ctrl.kref);
+       nvme_get_ctrl(&ctrl->ctrl);
 
        dev_info(ctrl->ctrl.device,
                "NVME-FC{%d}: new ctrl: NQN \"%s\"\n",

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index cb9d93048f3dbc8926e2f823fba42e8749a85691..ae60d8342e6014c10bfc04db2bd66695674116f2 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -127,12 +127,12 @@ struct nvme_ctrl {
        struct request_queue *admin_q;
        struct request_queue *connect_q;
        struct device *dev;
-       struct kref kref;
        int instance;
        struct blk_mq_tag_set *tagset;
        struct blk_mq_tag_set *admin_tagset;
        struct list_head namespaces;
        struct mutex namespaces_mutex;
+       struct device ctrl_device;
        struct device *device;  /* char device */
        struct list_head node;
        struct ida ns_ida;
@@ -279,6 +279,16 @@ static inline void nvme_end_request(struct request *req, __le16 status,
        blk_mq_complete_request(req);
 }
 
+static inline void nvme_get_ctrl(struct nvme_ctrl *ctrl)
+{
+       get_device(ctrl->device);
+}
+
+static inline void nvme_put_ctrl(struct nvme_ctrl *ctrl)
+{
+       put_device(ctrl->device);
+}
+
 void nvme_complete_rq(struct request *req);
 void nvme_cancel_request(struct request *req, void *data, bool reserved);
 bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 11e6fd9d0ba497d3752899f3c3d6596ee3d64da9..7735571ffc9ab54c24cc28be680d55d1de39bc46 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2292,7 +2292,7 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev, int status)
 {
        dev_warn(dev->ctrl.device, "Removing after probe failure status: %d\n", status);
 
-       kref_get(&dev->ctrl.kref);
+       nvme_get_ctrl(&dev->ctrl);
        nvme_dev_disable(dev, false);
        if (!schedule_work(&dev->remove_work))
                nvme_put_ctrl(&dev->ctrl);

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 4552744eff454aafd9e837b82627be4992fcdc91..62b58f9b7d00e9500d6ab2dea458fd6f568f9179 100644 (file)
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1793,8 +1793,7 @@ static int nvme_rdma_del_ctrl(struct nvme_ctrl *nctrl)
         * Keep a reference until all work is flushed since
         * __nvme_rdma_del_ctrl can free the ctrl mem
         */
-       if (!kref_get_unless_zero(&ctrl->ctrl.kref))
-               return -EBUSY;
+       nvme_get_ctrl(&ctrl->ctrl);
        ret = __nvme_rdma_del_ctrl(ctrl);
        if (!ret)
                flush_work(&ctrl->delete_work);
@@ -1955,7 +1954,7 @@ static struct nvme_ctrl *nvme_rdma_create_ctrl(struct device *dev,
        dev_info(ctrl->ctrl.device, "new ctrl: NQN \"%s\", addr %pISpcs\n",
                ctrl->ctrl.opts->subsysnqn, &ctrl->addr);
 
-       kref_get(&ctrl->ctrl.kref);
+       nvme_get_ctrl(&ctrl->ctrl);
 
        mutex_lock(&nvme_rdma_ctrl_mutex);
        list_add_tail(&ctrl->list, &nvme_rdma_ctrl_list);

diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index c56354e1e4c6109d5a23abf519cf3295683b98cd..f83e925fe64a6e33bcfbca1ed956e8204e1faacc 100644 (file)
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -642,7 +642,7 @@ static struct nvme_ctrl *nvme_loop_create_ctrl(struct device *dev,
        dev_info(ctrl->ctrl.device,
                 "new ctrl: \"%s\"\n", ctrl->ctrl.opts->subsysnqn);
 
-       kref_get(&ctrl->ctrl.kref);
+       nvme_get_ctrl(&ctrl->ctrl);
 
        changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
        WARN_ON_ONCE(!changed);