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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: Alex Chiang <achiang@hp.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Alexander Chiang 2010-02-02 19:08:30 +00:00 committed by Roland Dreier
parent 2b937afcab
commit 6aa2a86ec4
1 changed files with 9 additions and 36 deletions
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45
drivers/infiniband/core/user_mad.c
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@ -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;