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Gigaset: permit module unload
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Fix the initialization and reference counting of the Gigaset driver modules
so that they can be unloaded when they are not actually in use.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Cc: Greg KH <gregkh@suse.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tilman Schmidt authored and Linus Torvalds committed Feb 6, 2008
1 parent 9d4bee2 commit e468c04
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Showing 5 changed files with 85 additions and 142 deletions.
80 changes: 39 additions & 41 deletions drivers/isdn/gigaset/bas-gigaset.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,6 @@ struct bas_cardstate {


static struct gigaset_driver *driver = NULL;
static struct cardstate *cardstate = NULL;

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver gigaset_usb_driver = {
Expand Down Expand Up @@ -2247,11 +2246,11 @@ static int gigaset_probe(struct usb_interface *interface,
__func__, le16_to_cpu(udev->descriptor.idVendor),
le16_to_cpu(udev->descriptor.idProduct));

cs = gigaset_getunassignedcs(driver);
if (!cs) {
dev_err(&udev->dev, "no free cardstate\n");
/* allocate memory for our device state and intialize it */
cs = gigaset_initcs(driver, BAS_CHANNELS, 0, 0, cidmode,
GIGASET_MODULENAME);
if (!cs)
return -ENODEV;
}
ucs = cs->hw.bas;

/* save off device structure ptrs for later use */
Expand Down Expand Up @@ -2320,7 +2319,7 @@ static int gigaset_probe(struct usb_interface *interface,
error:
freeurbs(cs);
usb_set_intfdata(interface, NULL);
gigaset_unassign(cs);
gigaset_freecs(cs);
return -ENODEV;
}

Expand Down Expand Up @@ -2362,7 +2361,7 @@ static void gigaset_disconnect(struct usb_interface *interface)
ucs->interface = NULL;
ucs->udev = NULL;
cs->dev = NULL;
gigaset_unassign(cs);
gigaset_freecs(cs);
}

/* gigaset_suspend
Expand Down Expand Up @@ -2501,12 +2500,6 @@ static int __init bas_gigaset_init(void)
&gigops, THIS_MODULE)) == NULL)
goto error;

/* allocate memory for our device state and intialize it */
cardstate = gigaset_initcs(driver, BAS_CHANNELS, 0, 0, cidmode,
GIGASET_MODULENAME);
if (!cardstate)
goto error;

/* register this driver with the USB subsystem */
result = usb_register(&gigaset_usb_driver);
if (result < 0) {
Expand All @@ -2518,9 +2511,7 @@ static int __init bas_gigaset_init(void)
info(DRIVER_DESC);
return 0;

error: if (cardstate)
gigaset_freecs(cardstate);
cardstate = NULL;
error:
if (driver)
gigaset_freedriver(driver);
driver = NULL;
Expand All @@ -2532,43 +2523,50 @@ error: if (cardstate)
*/
static void __exit bas_gigaset_exit(void)
{
struct bas_cardstate *ucs = cardstate->hw.bas;
struct bas_cardstate *ucs;
int i;

gigaset_blockdriver(driver); /* => probe will fail
* => no gigaset_start any more
*/

gigaset_shutdown(cardstate);
/* from now on, no isdn callback should be possible */

/* close all still open channels */
if (ucs->basstate & BS_B1OPEN) {
gig_dbg(DEBUG_INIT, "closing B1 channel");
usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
HD_CLOSE_B1CHANNEL, OUT_VENDOR_REQ, 0, 0,
NULL, 0, BAS_TIMEOUT);
}
if (ucs->basstate & BS_B2OPEN) {
gig_dbg(DEBUG_INIT, "closing B2 channel");
usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
HD_CLOSE_B2CHANNEL, OUT_VENDOR_REQ, 0, 0,
NULL, 0, BAS_TIMEOUT);
}
if (ucs->basstate & BS_ATOPEN) {
gig_dbg(DEBUG_INIT, "closing AT channel");
usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
HD_CLOSE_ATCHANNEL, OUT_VENDOR_REQ, 0, 0,
NULL, 0, BAS_TIMEOUT);
/* stop all connected devices */
for (i = 0; i < driver->minors; i++) {
if (gigaset_shutdown(driver->cs + i) < 0)
continue; /* no device */
/* from now on, no isdn callback should be possible */

/* close all still open channels */
ucs = driver->cs[i].hw.bas;
if (ucs->basstate & BS_B1OPEN) {
gig_dbg(DEBUG_INIT, "closing B1 channel");
usb_control_msg(ucs->udev,
usb_sndctrlpipe(ucs->udev, 0),
HD_CLOSE_B1CHANNEL, OUT_VENDOR_REQ,
0, 0, NULL, 0, BAS_TIMEOUT);
}
if (ucs->basstate & BS_B2OPEN) {
gig_dbg(DEBUG_INIT, "closing B2 channel");
usb_control_msg(ucs->udev,
usb_sndctrlpipe(ucs->udev, 0),
HD_CLOSE_B2CHANNEL, OUT_VENDOR_REQ,
0, 0, NULL, 0, BAS_TIMEOUT);
}
if (ucs->basstate & BS_ATOPEN) {
gig_dbg(DEBUG_INIT, "closing AT channel");
usb_control_msg(ucs->udev,
usb_sndctrlpipe(ucs->udev, 0),
HD_CLOSE_ATCHANNEL, OUT_VENDOR_REQ,
0, 0, NULL, 0, BAS_TIMEOUT);
}
ucs->basstate = 0;
}
ucs->basstate = 0;

/* deregister this driver with the USB subsystem */
usb_deregister(&gigaset_usb_driver);
/* this will call the disconnect-callback */
/* from now on, no disconnect/probe callback should be running */

gigaset_freecs(cardstate);
cardstate = NULL;
gigaset_freedriver(driver);
driver = NULL;
}
Expand Down
105 changes: 29 additions & 76 deletions drivers/isdn/gigaset/common.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,6 @@ MODULE_PARM_DESC(debug, "debug level");
/* driver state flags */
#define VALID_MINOR 0x01
#define VALID_ID 0x02
#define ASSIGNED 0x04

void gigaset_dbg_buffer(enum debuglevel level, const unsigned char *msg,
size_t len, const unsigned char *buf)
Expand Down Expand Up @@ -178,7 +177,7 @@ int gigaset_get_channel(struct bc_state *bcs)
unsigned long flags;

spin_lock_irqsave(&bcs->cs->lock, flags);
if (bcs->use_count) {
if (bcs->use_count || !try_module_get(bcs->cs->driver->owner)) {
gig_dbg(DEBUG_ANY, "could not allocate channel %d",
bcs->channel);
spin_unlock_irqrestore(&bcs->cs->lock, flags);
Expand All @@ -203,6 +202,7 @@ void gigaset_free_channel(struct bc_state *bcs)
}
--bcs->use_count;
bcs->busy = 0;
module_put(bcs->cs->driver->owner);
gig_dbg(DEBUG_ANY, "freed channel %d", bcs->channel);
spin_unlock_irqrestore(&bcs->cs->lock, flags);
}
Expand Down Expand Up @@ -356,39 +356,36 @@ static struct cardstate *alloc_cs(struct gigaset_driver *drv)
{
unsigned long flags;
unsigned i;
struct cardstate *cs;
struct cardstate *ret = NULL;

spin_lock_irqsave(&drv->lock, flags);
if (drv->blocked)
goto exit;
for (i = 0; i < drv->minors; ++i) {
if (!(drv->flags[i] & VALID_MINOR)) {
if (try_module_get(drv->owner)) {
drv->flags[i] = VALID_MINOR;
ret = drv->cs + i;
}
cs = drv->cs + i;
if (!(cs->flags & VALID_MINOR)) {
cs->flags = VALID_MINOR;
ret = cs;
break;
}
}
exit:
spin_unlock_irqrestore(&drv->lock, flags);
return ret;
}

static void free_cs(struct cardstate *cs)
{
unsigned long flags;
struct gigaset_driver *drv = cs->driver;
spin_lock_irqsave(&drv->lock, flags);
if (drv->flags[cs->minor_index] & VALID_MINOR)
module_put(drv->owner);
drv->flags[cs->minor_index] = 0;
spin_unlock_irqrestore(&drv->lock, flags);
cs->flags = 0;
}

static void make_valid(struct cardstate *cs, unsigned mask)
{
unsigned long flags;
struct gigaset_driver *drv = cs->driver;
spin_lock_irqsave(&drv->lock, flags);
drv->flags[cs->minor_index] |= mask;
cs->flags |= mask;
spin_unlock_irqrestore(&drv->lock, flags);
}

Expand All @@ -397,7 +394,7 @@ static void make_invalid(struct cardstate *cs, unsigned mask)
unsigned long flags;
struct gigaset_driver *drv = cs->driver;
spin_lock_irqsave(&drv->lock, flags);
drv->flags[cs->minor_index] &= ~mask;
cs->flags &= ~mask;
spin_unlock_irqrestore(&drv->lock, flags);
}

Expand Down Expand Up @@ -893,10 +890,17 @@ int gigaset_start(struct cardstate *cs)
}
EXPORT_SYMBOL_GPL(gigaset_start);

void gigaset_shutdown(struct cardstate *cs)
/* gigaset_shutdown
* check if a device is associated to the cardstate structure and stop it
* return value: 0 if ok, -1 if no device was associated
*/
int gigaset_shutdown(struct cardstate *cs)
{
mutex_lock(&cs->mutex);

if (!(cs->flags & VALID_MINOR))
return -1;

cs->waiting = 1;

if (!gigaset_add_event(cs, &cs->at_state, EV_SHUTDOWN, NULL, 0, NULL)) {
Expand All @@ -913,6 +917,7 @@ void gigaset_shutdown(struct cardstate *cs)

exit:
mutex_unlock(&cs->mutex);
return 0;
}
EXPORT_SYMBOL_GPL(gigaset_shutdown);

Expand Down Expand Up @@ -954,13 +959,11 @@ struct cardstate *gigaset_get_cs_by_id(int id)
list_for_each_entry(drv, &drivers, list) {
spin_lock(&drv->lock);
for (i = 0; i < drv->minors; ++i) {
if (drv->flags[i] & VALID_ID) {
cs = drv->cs + i;
if (cs->myid == id)
ret = cs;
}
if (ret)
cs = drv->cs + i;
if ((cs->flags & VALID_ID) && cs->myid == id) {
ret = cs;
break;
}
}
spin_unlock(&drv->lock);
if (ret)
Expand All @@ -983,10 +986,9 @@ void gigaset_debugdrivers(void)
spin_lock(&drv->lock);
for (i = 0; i < drv->minors; ++i) {
gig_dbg(DEBUG_DRIVER, " index %u", i);
gig_dbg(DEBUG_DRIVER, " flags 0x%02x",
drv->flags[i]);
cs = drv->cs + i;
gig_dbg(DEBUG_DRIVER, " cardstate %p", cs);
gig_dbg(DEBUG_DRIVER, " flags 0x%02x", cs->flags);
gig_dbg(DEBUG_DRIVER, " minor_index %u",
cs->minor_index);
gig_dbg(DEBUG_DRIVER, " driver %p", cs->driver);
Expand All @@ -1010,7 +1012,7 @@ static struct cardstate *gigaset_get_cs_by_minor(unsigned minor)
continue;
index = minor - drv->minor;
spin_lock(&drv->lock);
if (drv->flags[index] & VALID_MINOR)
if (drv->cs[index].flags & VALID_MINOR)
ret = drv->cs + index;
spin_unlock(&drv->lock);
if (ret)
Expand Down Expand Up @@ -1038,7 +1040,6 @@ void gigaset_freedriver(struct gigaset_driver *drv)
gigaset_if_freedriver(drv);

kfree(drv->cs);
kfree(drv->flags);
kfree(drv);
}
EXPORT_SYMBOL_GPL(gigaset_freedriver);
Expand Down Expand Up @@ -1080,12 +1081,8 @@ struct gigaset_driver *gigaset_initdriver(unsigned minor, unsigned minors,
if (!drv->cs)
goto error;

drv->flags = kmalloc(minors * sizeof *drv->flags, GFP_KERNEL);
if (!drv->flags)
goto error;

for (i = 0; i < minors; ++i) {
drv->flags[i] = 0;
drv->cs[i].flags = 0;
drv->cs[i].driver = drv;
drv->cs[i].ops = drv->ops;
drv->cs[i].minor_index = i;
Expand All @@ -1106,53 +1103,9 @@ struct gigaset_driver *gigaset_initdriver(unsigned minor, unsigned minors,
}
EXPORT_SYMBOL_GPL(gigaset_initdriver);

/* For drivers without fixed assignment device<->cardstate (usb) */
struct cardstate *gigaset_getunassignedcs(struct gigaset_driver *drv)
{
unsigned long flags;
struct cardstate *cs = NULL;
unsigned i;

spin_lock_irqsave(&drv->lock, flags);
if (drv->blocked)
goto exit;
for (i = 0; i < drv->minors; ++i) {
if ((drv->flags[i] & VALID_MINOR) &&
!(drv->flags[i] & ASSIGNED)) {
drv->flags[i] |= ASSIGNED;
cs = drv->cs + i;
break;
}
}
exit:
spin_unlock_irqrestore(&drv->lock, flags);
return cs;
}
EXPORT_SYMBOL_GPL(gigaset_getunassignedcs);

void gigaset_unassign(struct cardstate *cs)
{
unsigned long flags;
unsigned *minor_flags;
struct gigaset_driver *drv;

if (!cs)
return;
drv = cs->driver;
spin_lock_irqsave(&drv->lock, flags);
minor_flags = drv->flags + cs->minor_index;
if (*minor_flags & VALID_MINOR)
*minor_flags &= ~ASSIGNED;
spin_unlock_irqrestore(&drv->lock, flags);
}
EXPORT_SYMBOL_GPL(gigaset_unassign);

void gigaset_blockdriver(struct gigaset_driver *drv)
{
unsigned long flags;
spin_lock_irqsave(&drv->lock, flags);
drv->blocked = 1;
spin_unlock_irqrestore(&drv->lock, flags);
}
EXPORT_SYMBOL_GPL(gigaset_blockdriver);

Expand Down
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