From a74968f8c3b1166cfe0942901b56165f06ab6f60 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Fri, 28 Oct 2005 15:37:23 -0700 Subject: [PATCH] [IB] umad: Fix device lifetime problems Move ib_umad module to using cdev_alloc() and class_device_create() so that we can handle device lifetime properly. Now we can make sure we keep all of our data structures around until the last way to reach them is gone. Signed-off-by: Roland Dreier --- drivers/infiniband/core/user_mad.c | 268 +++++++++++++++++------------ 1 file changed, 159 insertions(+), 109 deletions(-) diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index 17ec0a19db..9e49816d72 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -64,18 +64,39 @@ enum { IB_UMAD_MINOR_BASE = 0 }; +/* + * Our lifetime rules for these structs are the following: each time a + * device special file is opened, we look up the corresponding struct + * ib_umad_port by minor in the umad_port[] table while holding the + * port_lock. If this lookup succeeds, we take a reference on the + * ib_umad_port's struct ib_umad_device while still holding the + * port_lock; if the lookup fails, we fail the open(). We drop these + * references in the corresponding close(). + * + * In addition to references coming from open character devices, there + * is one more reference to each ib_umad_device representing the + * module's reference taken when allocating the ib_umad_device in + * ib_umad_add_one(). + * + * When destroying an ib_umad_device, we clear all of its + * ib_umad_ports from umad_port[] while holding port_lock before + * dropping the module's reference to the ib_umad_device. This is + * always safe because any open() calls will either succeed and obtain + * a reference before we clear the umad_port[] entries, or fail after + * we clear the umad_port[] entries. + */ + struct ib_umad_port { - int devnum; - struct cdev dev; - struct class_device class_dev; + struct cdev *dev; + struct class_device *class_dev; - int sm_devnum; - struct cdev sm_dev; - struct class_device sm_class_dev; + struct cdev *sm_dev; + struct class_device *sm_class_dev; struct semaphore sm_sem; struct ib_device *ib_dev; struct ib_umad_device *umad_dev; + int dev_num; u8 port_num; }; @@ -102,13 +123,25 @@ struct ib_umad_packet { struct ib_user_mad mad; }; +static struct class *umad_class; + static const dev_t base_dev = MKDEV(IB_UMAD_MAJOR, IB_UMAD_MINOR_BASE); -static spinlock_t map_lock; + +static DEFINE_SPINLOCK(port_lock); +static struct ib_umad_port *umad_port[IB_UMAD_MAX_PORTS]; static DECLARE_BITMAP(dev_map, IB_UMAD_MAX_PORTS * 2); static void ib_umad_add_one(struct ib_device *device); static void ib_umad_remove_one(struct ib_device *device); +static void ib_umad_release_dev(struct kref *ref) +{ + struct ib_umad_device *dev = + container_of(ref, struct ib_umad_device, ref); + + kfree(dev); +} + static int queue_packet(struct ib_umad_file *file, struct ib_mad_agent *agent, struct ib_umad_packet *packet) @@ -534,13 +567,23 @@ static long ib_umad_ioctl(struct file *filp, unsigned int cmd, static int ib_umad_open(struct inode *inode, struct file *filp) { - struct ib_umad_port *port = - container_of(inode->i_cdev, struct ib_umad_port, dev); + struct ib_umad_port *port; struct ib_umad_file *file; + spin_lock(&port_lock); + port = umad_port[iminor(inode) - IB_UMAD_MINOR_BASE]; + if (port) + kref_get(&port->umad_dev->ref); + spin_unlock(&port_lock); + + if (!port) + return -ENXIO; + file = kzalloc(sizeof *file, GFP_KERNEL); - if (!file) + if (!file) { + kref_put(&port->umad_dev->ref, ib_umad_release_dev); return -ENOMEM; + } spin_lock_init(&file->recv_lock); init_rwsem(&file->agent_mutex); @@ -556,6 +599,7 @@ static int ib_umad_open(struct inode *inode, struct file *filp) static int ib_umad_close(struct inode *inode, struct file *filp) { struct ib_umad_file *file = filp->private_data; + struct ib_umad_device *dev = file->port->umad_dev; struct ib_umad_packet *packet, *tmp; int i; @@ -570,6 +614,8 @@ static int ib_umad_close(struct inode *inode, struct file *filp) kfree(file); + kref_put(&dev->ref, ib_umad_release_dev); + return 0; } @@ -586,30 +632,46 @@ static struct file_operations umad_fops = { static int ib_umad_sm_open(struct inode *inode, struct file *filp) { - struct ib_umad_port *port = - container_of(inode->i_cdev, struct ib_umad_port, sm_dev); + struct ib_umad_port *port; struct ib_port_modify props = { .set_port_cap_mask = IB_PORT_SM }; int ret; + spin_lock(&port_lock); + port = umad_port[iminor(inode) - IB_UMAD_MINOR_BASE - IB_UMAD_MAX_PORTS]; + if (port) + kref_get(&port->umad_dev->ref); + spin_unlock(&port_lock); + + if (!port) + return -ENXIO; + if (filp->f_flags & O_NONBLOCK) { - if (down_trylock(&port->sm_sem)) - return -EAGAIN; + if (down_trylock(&port->sm_sem)) { + ret = -EAGAIN; + goto fail; + } } else { - if (down_interruptible(&port->sm_sem)) - return -ERESTARTSYS; + if (down_interruptible(&port->sm_sem)) { + ret = -ERESTARTSYS; + goto fail; + } } ret = ib_modify_port(port->ib_dev, port->port_num, 0, &props); if (ret) { up(&port->sm_sem); - return ret; + goto fail; } filp->private_data = port; return 0; + +fail: + kref_put(&port->umad_dev->ref, ib_umad_release_dev); + return ret; } static int ib_umad_sm_close(struct inode *inode, struct file *filp) @@ -623,6 +685,8 @@ static int ib_umad_sm_close(struct inode *inode, struct file *filp) ret = ib_modify_port(port->ib_dev, port->port_num, 0, &props); up(&port->sm_sem); + kref_put(&port->umad_dev->ref, ib_umad_release_dev); + return ret; } @@ -642,6 +706,9 @@ static ssize_t show_ibdev(struct class_device *class_dev, char *buf) { struct ib_umad_port *port = class_get_devdata(class_dev); + if (!port) + return -ENODEV; + return sprintf(buf, "%s\n", port->ib_dev->name); } static CLASS_DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL); @@ -650,38 +717,13 @@ static ssize_t show_port(struct class_device *class_dev, char *buf) { struct ib_umad_port *port = class_get_devdata(class_dev); + if (!port) + return -ENODEV; + return sprintf(buf, "%d\n", port->port_num); } static CLASS_DEVICE_ATTR(port, S_IRUGO, show_port, NULL); -static void ib_umad_release_dev(struct kref *ref) -{ - struct ib_umad_device *dev = - container_of(ref, struct ib_umad_device, ref); - - kfree(dev); -} - -static void ib_umad_release_port(struct class_device *class_dev) -{ - struct ib_umad_port *port = class_get_devdata(class_dev); - - if (class_dev == &port->class_dev) { - cdev_del(&port->dev); - clear_bit(port->devnum, dev_map); - } else { - cdev_del(&port->sm_dev); - clear_bit(port->sm_devnum, dev_map); - } - - kref_put(&port->umad_dev->ref, ib_umad_release_dev); -} - -static struct class umad_class = { - .name = "infiniband_mad", - .release = ib_umad_release_port -}; - static ssize_t show_abi_version(struct class *class, char *buf) { return sprintf(buf, "%d\n", IB_USER_MAD_ABI_VERSION); @@ -691,89 +733,102 @@ static CLASS_ATTR(abi_version, S_IRUGO, show_abi_version, NULL); static int ib_umad_init_port(struct ib_device *device, int port_num, struct ib_umad_port *port) { - spin_lock(&map_lock); - port->devnum = find_first_zero_bit(dev_map, IB_UMAD_MAX_PORTS); - if (port->devnum >= IB_UMAD_MAX_PORTS) { - spin_unlock(&map_lock); + spin_lock(&port_lock); + port->dev_num = find_first_zero_bit(dev_map, IB_UMAD_MAX_PORTS); + if (port->dev_num >= IB_UMAD_MAX_PORTS) { + spin_unlock(&port_lock); return -1; } - port->sm_devnum = find_next_zero_bit(dev_map, IB_UMAD_MAX_PORTS * 2, IB_UMAD_MAX_PORTS); - if (port->sm_devnum >= IB_UMAD_MAX_PORTS * 2) { - spin_unlock(&map_lock); - return -1; - } - set_bit(port->devnum, dev_map); - set_bit(port->sm_devnum, dev_map); - spin_unlock(&map_lock); + set_bit(port->dev_num, dev_map); + spin_unlock(&port_lock); port->ib_dev = device; port->port_num = port_num; init_MUTEX(&port->sm_sem); - cdev_init(&port->dev, &umad_fops); - port->dev.owner = THIS_MODULE; - kobject_set_name(&port->dev.kobj, "umad%d", port->devnum); - if (cdev_add(&port->dev, base_dev + port->devnum, 1)) + port->dev = cdev_alloc(); + if (!port->dev) return -1; - - port->class_dev.class = &umad_class; - port->class_dev.dev = device->dma_device; - port->class_dev.devt = port->dev.dev; - - snprintf(port->class_dev.class_id, BUS_ID_SIZE, "umad%d", port->devnum); - - if (class_device_register(&port->class_dev)) + port->dev->owner = THIS_MODULE; + port->dev->ops = &umad_fops; + kobject_set_name(&port->dev->kobj, "umad%d", port->dev_num); + if (cdev_add(port->dev, base_dev + port->dev_num, 1)) goto err_cdev; - class_set_devdata(&port->class_dev, port); - kref_get(&port->umad_dev->ref); + port->class_dev = class_device_create(umad_class, port->dev->dev, + device->dma_device, + "umad%d", port->dev_num); + if (IS_ERR(port->class_dev)) + goto err_cdev; - if (class_device_create_file(&port->class_dev, &class_device_attr_ibdev)) + if (class_device_create_file(port->class_dev, &class_device_attr_ibdev)) goto err_class; - if (class_device_create_file(&port->class_dev, &class_device_attr_port)) + if (class_device_create_file(port->class_dev, &class_device_attr_port)) goto err_class; - cdev_init(&port->sm_dev, &umad_sm_fops); - port->sm_dev.owner = THIS_MODULE; - kobject_set_name(&port->dev.kobj, "issm%d", port->sm_devnum - IB_UMAD_MAX_PORTS); - if (cdev_add(&port->sm_dev, base_dev + port->sm_devnum, 1)) - return -1; - - port->sm_class_dev.class = &umad_class; - port->sm_class_dev.dev = device->dma_device; - port->sm_class_dev.devt = port->sm_dev.dev; - - snprintf(port->sm_class_dev.class_id, BUS_ID_SIZE, "issm%d", port->sm_devnum - IB_UMAD_MAX_PORTS); + port->sm_dev = cdev_alloc(); + if (!port->sm_dev) + goto err_class; + port->sm_dev->owner = THIS_MODULE; + port->sm_dev->ops = &umad_sm_fops; + kobject_set_name(&port->dev->kobj, "issm%d", port->dev_num); + if (cdev_add(port->sm_dev, base_dev + port->dev_num + IB_UMAD_MAX_PORTS, 1)) + goto err_sm_cdev; - if (class_device_register(&port->sm_class_dev)) + port->sm_class_dev = class_device_create(umad_class, port->sm_dev->dev, + device->dma_device, + "issm%d", port->dev_num); + if (IS_ERR(port->sm_class_dev)) goto err_sm_cdev; - class_set_devdata(&port->sm_class_dev, port); - kref_get(&port->umad_dev->ref); + class_set_devdata(port->class_dev, port); + class_set_devdata(port->sm_class_dev, port); - if (class_device_create_file(&port->sm_class_dev, &class_device_attr_ibdev)) + if (class_device_create_file(port->sm_class_dev, &class_device_attr_ibdev)) goto err_sm_class; - if (class_device_create_file(&port->sm_class_dev, &class_device_attr_port)) + if (class_device_create_file(port->sm_class_dev, &class_device_attr_port)) goto err_sm_class; + spin_lock(&port_lock); + umad_port[port->dev_num] = port; + spin_unlock(&port_lock); + return 0; err_sm_class: - class_device_unregister(&port->sm_class_dev); + class_device_destroy(umad_class, port->sm_dev->dev); err_sm_cdev: - cdev_del(&port->sm_dev); + cdev_del(port->sm_dev); err_class: - class_device_unregister(&port->class_dev); + class_device_destroy(umad_class, port->dev->dev); err_cdev: - cdev_del(&port->dev); - clear_bit(port->devnum, dev_map); + cdev_del(port->dev); + clear_bit(port->dev_num, dev_map); return -1; } +static void ib_umad_kill_port(struct ib_umad_port *port) +{ + class_set_devdata(port->class_dev, NULL); + class_set_devdata(port->sm_class_dev, NULL); + + class_device_destroy(umad_class, port->dev->dev); + class_device_destroy(umad_class, port->sm_dev->dev); + + cdev_del(port->dev); + cdev_del(port->sm_dev); + + spin_lock(&port_lock); + umad_port[port->dev_num] = NULL; + spin_unlock(&port_lock); + + clear_bit(port->dev_num, dev_map); +} + static void ib_umad_add_one(struct ib_device *device) { struct ib_umad_device *umad_dev; @@ -809,10 +864,8 @@ static void ib_umad_add_one(struct ib_device *device) return; err: - while (--i >= s) { - class_device_unregister(&umad_dev->port[i - s].class_dev); - class_device_unregister(&umad_dev->port[i - s].sm_class_dev); - } + while (--i >= s) + ib_umad_kill_port(&umad_dev->port[i]); kref_put(&umad_dev->ref, ib_umad_release_dev); } @@ -825,10 +878,8 @@ static void ib_umad_remove_one(struct ib_device *device) if (!umad_dev) return; - for (i = 0; i <= umad_dev->end_port - umad_dev->start_port; ++i) { - class_device_unregister(&umad_dev->port[i].class_dev); - class_device_unregister(&umad_dev->port[i].sm_class_dev); - } + for (i = 0; i <= umad_dev->end_port - umad_dev->start_port; ++i) + ib_umad_kill_port(&umad_dev->port[i]); kref_put(&umad_dev->ref, ib_umad_release_dev); } @@ -837,8 +888,6 @@ static int __init ib_umad_init(void) { int ret; - spin_lock_init(&map_lock); - ret = register_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2, "infiniband_mad"); if (ret) { @@ -846,13 +895,14 @@ static int __init ib_umad_init(void) goto out; } - ret = class_register(&umad_class); - if (ret) { + umad_class = class_create(THIS_MODULE, "infiniband_mad"); + if (IS_ERR(umad_class)) { + ret = PTR_ERR(umad_class); printk(KERN_ERR "user_mad: couldn't create class infiniband_mad\n"); goto out_chrdev; } - ret = class_create_file(&umad_class, &class_attr_abi_version); + ret = class_create_file(umad_class, &class_attr_abi_version); if (ret) { printk(KERN_ERR "user_mad: couldn't create abi_version attribute\n"); goto out_class; @@ -867,7 +917,7 @@ static int __init ib_umad_init(void) return 0; out_class: - class_unregister(&umad_class); + class_destroy(umad_class); out_chrdev: unregister_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2); @@ -879,7 +929,7 @@ out: static void __exit ib_umad_cleanup(void) { ib_unregister_client(&umad_client); - class_unregister(&umad_class); + class_destroy(umad_class); unregister_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2); } -- 2.39.5