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Commit 6aa2a86e authored by Alexander Chiang's avatar Alexander Chiang Committed by Roland Dreier
Browse files

IB/umad: Remove port_table[] 



We no longer need this data structure, as it was used to associate an
inode back to a struct ib_umad_port during ->open().  But now that
we're embedding a struct cdev in struct ib_umad_port, we can use the
container_of() macro to go from the inode back to the device instead.

Signed-off-by: default avatarAlex Chiang <achiang@hp.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 2b937afc

drivers/infiniband/core/user_mad.c

+9 −36
Original line number Diff line number Diff line
@@ -65,12 +65,9 @@ enum { 
};



/*

 * 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

 * Our lifetime rules for these structs are the following:

 * device special file is opened, we take a reference on the

 * ib_umad_port's struct ib_umad_device. We drop these

 * references in the corresponding close().

 *

 * In addition to references coming from open character devices, there
@@ -78,12 +75,7 @@ enum { 
 * 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.

 * When destroying an ib_umad_device, we drop the module's reference.

 */



struct ib_umad_port {
@@ -136,7 +128,6 @@ static struct class *umad_class; 
static const dev_t base_dev = MKDEV(IB_UMAD_MAJOR, IB_UMAD_MINOR_BASE);



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);



static void ib_umad_add_one(struct ib_device *device);
@@ -779,15 +770,11 @@ static long ib_umad_compat_ioctl(struct file *filp, unsigned int cmd, 
/*

 * ib_umad_open() does not need the BKL:

 *

 *  - umad_port[] accesses are protected by port_lock, the

 *    ib_umad_port structures are properly reference counted, and

 *  - the ib_umad_port structures are properly reference counted, and

 *    everything else is purely local to the file being created, so

 *    races against other open calls are not a problem;

 *  - the ioctl method does not affect any global state outside of the

 *    file structure being operated on;

 *  - the port is added to umad_port[] as the last part of module

 *    initialization so the open method will either immediately run

 *    -ENXIO, or all required initialization will be done.

 */

static int ib_umad_open(struct inode *inode, struct file *filp)

{
@@ -795,13 +782,10 @@ static int ib_umad_open(struct inode *inode, struct file *filp) 
	struct ib_umad_file *file;

	int ret = 0;



	spin_lock(&port_lock);

	port = umad_port[iminor(inode) - IB_UMAD_MINOR_BASE];

	port = container_of(inode->i_cdev, struct ib_umad_port, cdev);

	if (port)

		kref_get(&port->umad_dev->ref);

	spin_unlock(&port_lock);



	if (!port)

	else

		return -ENXIO;



	mutex_lock(&port->file_mutex);
@@ -892,13 +876,10 @@ static int ib_umad_sm_open(struct inode *inode, struct file *filp) 
	};

	int ret;



	spin_lock(&port_lock);

	port = umad_port[iminor(inode) - IB_UMAD_MINOR_BASE - IB_UMAD_MAX_PORTS];

	port = container_of(inode->i_cdev, struct ib_umad_port, sm_cdev);

	if (port)

		kref_get(&port->umad_dev->ref);

	spin_unlock(&port_lock);



	if (!port)

	else

		return -ENXIO;



	if (filp->f_flags & O_NONBLOCK) {
@@ -1042,10 +1023,6 @@ static int ib_umad_init_port(struct ib_device *device, int port_num, 
	if (device_create_file(port->sm_dev, &dev_attr_port))

		goto err_sm_dev;



	spin_lock(&port_lock);

	umad_port[port->dev_num] = port;

	spin_unlock(&port_lock);



	return 0;



err_sm_dev:
@@ -1079,10 +1056,6 @@ static void ib_umad_kill_port(struct ib_umad_port *port) 
	cdev_del(&port->cdev);

	cdev_del(&port->sm_cdev);



	spin_lock(&port_lock);

	umad_port[port->dev_num] = NULL;

	spin_unlock(&port_lock);



	mutex_lock(&port->file_mutex);



	port->ib_dev = NULL;