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IB/ucm: utilize new cdev_device_add helper function 

The use after free is not triggerable here because the cdev holds
the module lock and the only device_unregister is only triggered by
module unload, however make the change for consistency.

To make this work the cdev_del needs to move out of the struct device
release function.

This cleans up the error path significantly and thus also fixes a minor
bug where the devnum would not be released if cdev_add failed.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason Gunthorpe 2017-03-17 12:48:15 -06:00 committed by Greg Kroah-Hartman
parent 1c1d152cc5
commit a0d78193dc
1 changed files with 18 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
drivers/infiniband/core/ucm.c
View File

@ -1205,12 +1205,15 @@ static void ib_ucm_release_dev(struct device *dev)
struct ib_ucm_device *ucm_dev;
ucm_dev = container_of(dev, struct ib_ucm_device, dev);
cdev_del(&ucm_dev->cdev);
kfree(ucm_dev);
}
static void ib_ucm_free_dev(struct ib_ucm_device *ucm_dev)
{
if (ucm_dev->devnum < IB_UCM_MAX_DEVICES)
clear_bit(ucm_dev->devnum, dev_map);
else
clear_bit(ucm_dev->devnum - IB_UCM_MAX_DEVICES, overflow_map);
kfree(ucm_dev);
}
static const struct file_operations ucm_fops = {
@ -1266,7 +1269,9 @@ static void ib_ucm_add_one(struct ib_device *device)
if (!ucm_dev)
return;
device_initialize(&ucm_dev->dev);
ucm_dev->ib_dev = device;
ucm_dev->dev.release = ib_ucm_release_dev;
devnum = find_first_zero_bit(dev_map, IB_UCM_MAX_DEVICES);
if (devnum >= IB_UCM_MAX_DEVICES) {
@ -1286,16 +1291,14 @@ static void ib_ucm_add_one(struct ib_device *device)
cdev_init(&ucm_dev->cdev, &ucm_fops);
ucm_dev->cdev.owner = THIS_MODULE;
kobject_set_name(&ucm_dev->cdev.kobj, "ucm%d", ucm_dev->devnum);
if (cdev_add(&ucm_dev->cdev, base, 1))
goto err;
ucm_dev->dev.class = &cm_class;
ucm_dev->dev.parent = device->dev.parent;
ucm_dev->dev.devt = ucm_dev->cdev.dev;
ucm_dev->dev.release = ib_ucm_release_dev;
ucm_dev->dev.devt = base;
dev_set_name(&ucm_dev->dev, "ucm%d", ucm_dev->devnum);
if (device_register(&ucm_dev->dev))
goto err_cdev;
if (cdev_device_add(&ucm_dev->cdev, &ucm_dev->dev))
goto err_devnum;
if (device_create_file(&ucm_dev->dev, &dev_attr_ibdev))
goto err_dev;
@ -1304,15 +1307,11 @@ static void ib_ucm_add_one(struct ib_device *device)
return;
err_dev:
device_unregister(&ucm_dev->dev);
err_cdev:
cdev_del(&ucm_dev->cdev);
if (ucm_dev->devnum < IB_UCM_MAX_DEVICES)
clear_bit(devnum, dev_map);
else
clear_bit(devnum, overflow_map);
cdev_device_del(&ucm_dev->cdev, &ucm_dev->dev);
err_devnum:
ib_ucm_free_dev(ucm_dev);
err:
kfree(ucm_dev);
put_device(&ucm_dev->dev);
return;
}
@ -1323,7 +1322,9 @@ static void ib_ucm_remove_one(struct ib_device *device, void *client_data)
if (!ucm_dev)
return;
device_unregister(&ucm_dev->dev);
cdev_device_del(&ucm_dev->cdev, &ucm_dev->dev);
ib_ucm_free_dev(ucm_dev);
put_device(&ucm_dev->dev);
}
static CLASS_ATTR_STRING(abi_version, S_IRUGO,