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RDMA/uverbs: Use cdev_device_add() instead of cdev_add()
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Instead of doing two step process to add char device and create underlying
device, use cdev_device_add() which does both.

Currently a kobject per uverbs_device is created to keep reference to its
holding ib_uverbs_device in addition to its underlying device 'dev'.

Instead just use uverbs_device->dev to keep a reference to.

With this change there is single reference tracker for ib_uverbs_device
structure.

This allows for subsequent patch to registers group attribute as well
using single API cdev_device_add().

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
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Parav Pandit authored and Jason Gunthorpe committed Sep 5, 2018
1 parent adee9f3 commit c5c4d92
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Showing 2 changed files with 30 additions and 39 deletions.
3 changes: 1 addition & 2 deletions drivers/infiniband/core/uverbs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -100,13 +100,12 @@ struct ib_uverbs_device {
atomic_t refcount;
int num_comp_vectors;
struct completion comp;
struct device *dev;
struct device dev;
struct ib_device __rcu *ib_dev;
int devnum;
struct cdev cdev;
struct rb_root xrcd_tree;
struct mutex xrcd_tree_mutex;
struct kobject kobj;
struct srcu_struct disassociate_srcu;
struct mutex lists_mutex; /* protect lists */
struct list_head uverbs_file_list;
Expand Down
66 changes: 29 additions & 37 deletions drivers/infiniband/core/uverbs_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -169,20 +169,16 @@ int uverbs_dealloc_mw(struct ib_mw *mw)
return ret;
}

static void ib_uverbs_release_dev(struct kobject *kobj)
static void ib_uverbs_release_dev(struct device *device)
{
struct ib_uverbs_device *dev =
container_of(kobj, struct ib_uverbs_device, kobj);
container_of(device, struct ib_uverbs_device, dev);

uverbs_destroy_api(dev->uapi);
cleanup_srcu_struct(&dev->disassociate_srcu);
kfree(dev);
}

static struct kobj_type ib_uverbs_dev_ktype = {
.release = ib_uverbs_release_dev,
};

static void ib_uverbs_release_async_event_file(struct kref *ref)
{
struct ib_uverbs_async_event_file *file =
Expand Down Expand Up @@ -265,7 +261,7 @@ void ib_uverbs_release_file(struct kref *ref)
if (atomic_dec_and_test(&file->device->refcount))
ib_uverbs_comp_dev(file->device);

kobject_put(&file->device->kobj);
put_device(&file->device->dev);
kfree(file);
}

Expand Down Expand Up @@ -838,6 +834,7 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
if (!atomic_inc_not_zero(&dev->refcount))
return -ENXIO;

get_device(&dev->dev);
srcu_key = srcu_read_lock(&dev->disassociate_srcu);
mutex_lock(&dev->lists_mutex);
ib_dev = srcu_dereference(dev->ib_dev,
Expand Down Expand Up @@ -877,7 +874,6 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
init_rwsem(&file->hw_destroy_rwsem);

filp->private_data = file;
kobject_get(&dev->kobj);
list_add_tail(&file->list, &dev->uverbs_file_list);
mutex_unlock(&dev->lists_mutex);
srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
Expand All @@ -898,6 +894,7 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
if (atomic_dec_and_test(&dev->refcount))
ib_uverbs_comp_dev(dev);

put_device(&dev->dev);
return ret;
}

Expand Down Expand Up @@ -953,14 +950,12 @@ static struct ib_client uverbs_client = {
static ssize_t show_ibdev(struct device *device, struct device_attribute *attr,
char *buf)
{
struct ib_uverbs_device *dev =
container_of(device, struct ib_uverbs_device, dev);
int ret = -ENODEV;
int srcu_key;
struct ib_uverbs_device *dev = dev_get_drvdata(device);
struct ib_device *ib_dev;

if (!dev)
return -ENODEV;

srcu_key = srcu_read_lock(&dev->disassociate_srcu);
ib_dev = srcu_dereference(dev->ib_dev, &dev->disassociate_srcu);
if (ib_dev)
Expand All @@ -974,13 +969,12 @@ static DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);
static ssize_t show_dev_abi_version(struct device *device,
struct device_attribute *attr, char *buf)
{
struct ib_uverbs_device *dev = dev_get_drvdata(device);
struct ib_uverbs_device *dev =
container_of(device, struct ib_uverbs_device, dev);
int ret = -ENODEV;
int srcu_key;
struct ib_device *ib_dev;

if (!dev)
return -ENODEV;
srcu_key = srcu_read_lock(&dev->disassociate_srcu);
ib_dev = srcu_dereference(dev->ib_dev, &dev->disassociate_srcu);
if (ib_dev)
Expand Down Expand Up @@ -1031,7 +1025,6 @@ static void ib_uverbs_add_one(struct ib_device *device)
init_completion(&uverbs_dev->comp);
uverbs_dev->xrcd_tree = RB_ROOT;
mutex_init(&uverbs_dev->xrcd_tree_mutex);
kobject_init(&uverbs_dev->kobj, &ib_uverbs_dev_ktype);
mutex_init(&uverbs_dev->lists_mutex);
INIT_LIST_HEAD(&uverbs_dev->uverbs_file_list);
INIT_LIST_HEAD(&uverbs_dev->uverbs_events_file_list);
Expand All @@ -1052,40 +1045,41 @@ static void ib_uverbs_add_one(struct ib_device *device)
if (ib_uverbs_create_uapi(device, uverbs_dev))
goto err_uapi;

cdev_init(&uverbs_dev->cdev, NULL);
device_initialize(&uverbs_dev->dev);
uverbs_dev->dev.class = uverbs_class;
uverbs_dev->dev.parent = device->dev.parent;
uverbs_dev->dev.devt = base;
uverbs_dev->dev.release = ib_uverbs_release_dev;
dev_set_name(&uverbs_dev->dev, "uverbs%d", uverbs_dev->devnum);

cdev_init(&uverbs_dev->cdev,
device->mmap ? &uverbs_mmap_fops : &uverbs_fops);
uverbs_dev->cdev.owner = THIS_MODULE;
uverbs_dev->cdev.ops = device->mmap ? &uverbs_mmap_fops : &uverbs_fops;
cdev_set_parent(&uverbs_dev->cdev, &uverbs_dev->kobj);
kobject_set_name(&uverbs_dev->cdev.kobj, "uverbs%d", uverbs_dev->devnum);
if (cdev_add(&uverbs_dev->cdev, base, 1))
goto err_cdev;

uverbs_dev->dev = device_create(uverbs_class, device->dev.parent,
uverbs_dev->cdev.dev, uverbs_dev,
"uverbs%d", uverbs_dev->devnum);
if (IS_ERR(uverbs_dev->dev))
ret = cdev_device_add(&uverbs_dev->cdev, &uverbs_dev->dev);
if (ret)
goto err_cdev;

if (device_create_file(uverbs_dev->dev, &dev_attr_ibdev))
goto err_class;
if (device_create_file(uverbs_dev->dev, &dev_attr_abi_version))
goto err_class;
if (device_create_file(&uverbs_dev->dev, &dev_attr_ibdev))
goto err_file;
if (device_create_file(&uverbs_dev->dev, &dev_attr_abi_version))
goto err_file;

ib_set_client_data(device, &uverbs_client, uverbs_dev);

return;

err_class:
device_destroy(uverbs_class, uverbs_dev->cdev.dev);
err_file:
cdev_device_del(&uverbs_dev->cdev, &uverbs_dev->dev);
err_cdev:
cdev_del(&uverbs_dev->cdev);
put_device(&uverbs_dev->dev);
err_uapi:
clear_bit(devnum, dev_map);
err:
if (atomic_dec_and_test(&uverbs_dev->refcount))
ib_uverbs_comp_dev(uverbs_dev);
wait_for_completion(&uverbs_dev->comp);
kobject_put(&uverbs_dev->kobj);
return;
}

Expand Down Expand Up @@ -1155,9 +1149,7 @@ static void ib_uverbs_remove_one(struct ib_device *device, void *client_data)
if (!uverbs_dev)
return;

dev_set_drvdata(uverbs_dev->dev, NULL);
device_destroy(uverbs_class, uverbs_dev->cdev.dev);
cdev_del(&uverbs_dev->cdev);
cdev_device_del(&uverbs_dev->cdev, &uverbs_dev->dev);
clear_bit(uverbs_dev->devnum, dev_map);

if (device->disassociate_ucontext) {
Expand All @@ -1181,7 +1173,7 @@ static void ib_uverbs_remove_one(struct ib_device *device, void *client_data)
if (wait_clients)
wait_for_completion(&uverbs_dev->comp);

kobject_put(&uverbs_dev->kobj);
put_device(&uverbs_dev->dev);
}

static char *uverbs_devnode(struct device *dev, umode_t *mode)
Expand Down

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