Re: [1/3] gigaset: avoid registering CAPI driver more than once

From: Karsten Keil
Date: Mon Mar 15 2010 - 10:56:36 EST


Registering/unregistering the Gigaset CAPI driver when a device is
connected/disconnected causes an Oops when disconnecting two Gigaset
devices in a row, because the same capi_driver structure gets
unregistered twice. Fix by making driver registration/unregistration
a separate operation (empty in the ISDN4Linux case) called when the
main module is loaded/unloaded.

Impact: bugfix
Signed-off-by: Tilman Schmidt <tilman@xxxxxxx>
Acked-by: Karsten Keil <keil@xxxxxxxxxxxxx>

---
Note to -stable: applies correctly to 2.6.33 with fuzz 2 in capi.c.

drivers/isdn/gigaset/capi.c | 44 ++++++++++++++++++++++-----------------
drivers/isdn/gigaset/common.c | 6 +++-
drivers/isdn/gigaset/gigaset.h | 6 +++-
drivers/isdn/gigaset/i4l.c | 28 ++++++++++++++++++-------
4 files changed, 53 insertions(+), 31 deletions(-)

diff --git a/drivers/isdn/gigaset/capi.c b/drivers/isdn/gigaset/capi.c
index 6643d65..4a31962 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -2191,36 +2191,24 @@ static const struct file_operations gigaset_proc_fops = {
.release = single_release,
};

-static struct capi_driver capi_driver_gigaset = {
- .name = "gigaset",
- .revision = "1.0",
-};
-
/**
- * gigaset_isdn_register() - register to LL
+ * gigaset_isdn_regdev() - register device to LL
* @cs: device descriptor structure.
* @isdnid: device name.
*
- * Called by main module to register the device with the LL.
- *
* Return value: 1 for success, 0 for failure
*/
-int gigaset_isdn_register(struct cardstate *cs, const char *isdnid)
+int gigaset_isdn_regdev(struct cardstate *cs, const char *isdnid)
{
struct gigaset_capi_ctr *iif;
int rc;

- pr_info("Kernel CAPI interface\n");
-
iif = kmalloc(sizeof(*iif), GFP_KERNEL);
if (!iif) {
pr_err("%s: out of memory\n", __func__);
return 0;
}

- /* register driver with CAPI (ToDo: what for?) */
- register_capi_driver(&capi_driver_gigaset);
-
/* prepare controller structure */
iif->ctr.owner = THIS_MODULE;
iif->ctr.driverdata = cs;
@@ -2241,7 +2229,6 @@ int gigaset_isdn_register(struct cardstate *cs, const char *isdnid)
rc = attach_capi_ctr(&iif->ctr);
if (rc) {
pr_err("attach_capi_ctr failed (%d)\n", rc);
- unregister_capi_driver(&capi_driver_gigaset);
kfree(iif);
return 0;
}
@@ -2252,17 +2239,36 @@ int gigaset_isdn_register(struct cardstate *cs, const char *isdnid)
}

/**
- * gigaset_isdn_unregister() - unregister from LL
+ * gigaset_isdn_unregdev() - unregister device from LL
* @cs: device descriptor structure.
- *
- * Called by main module to unregister the device from the LL.
*/
-void gigaset_isdn_unregister(struct cardstate *cs)
+void gigaset_isdn_unregdev(struct cardstate *cs)
{
struct gigaset_capi_ctr *iif = cs->iif;

detach_capi_ctr(&iif->ctr);
kfree(iif);
cs->iif = NULL;
+}
+
+static struct capi_driver capi_driver_gigaset = {
+ .name = "gigaset",
+ .revision = "1.0",
+};
+
+/**
+ * gigaset_isdn_regdrv() - register driver to LL
+ */
+void gigaset_isdn_regdrv(void)
+{
+ pr_info("Kernel CAPI interface\n");
+ register_capi_driver(&capi_driver_gigaset);
+}
+
+/**
+ * gigaset_isdn_unregdrv() - unregister driver from LL
+ */
+void gigaset_isdn_unregdrv(void)
+{
unregister_capi_driver(&capi_driver_gigaset);
}
diff --git a/drivers/isdn/gigaset/common.c b/drivers/isdn/gigaset/common.c
index 85de339..bdc01cb 100644
--- a/drivers/isdn/gigaset/common.c
+++ b/drivers/isdn/gigaset/common.c
@@ -507,7 +507,7 @@ void gigaset_freecs(struct cardstate *cs)
case 2: /* error in initcshw */
/* Deregister from LL */
make_invalid(cs, VALID_ID);
- gigaset_isdn_unregister(cs);
+ gigaset_isdn_unregdev(cs);

/* fall through */
case 1: /* error when registering to LL */
@@ -769,7 +769,7 @@ struct cardstate *gigaset_initcs(struct gigaset_driver *drv, int channels,
cs->cmdbytes = 0;

gig_dbg(DEBUG_INIT, "setting up iif");
- if (!gigaset_isdn_register(cs, modulename)) {
+ if (!gigaset_isdn_regdev(cs, modulename)) {
pr_err("error registering ISDN device\n");
goto error;
}
@@ -1205,11 +1205,13 @@ static int __init gigaset_init_module(void)
gigaset_debuglevel = DEBUG_DEFAULT;

pr_info(DRIVER_DESC DRIVER_DESC_DEBUG "\n");
+ gigaset_isdn_regdrv();
return 0;
}

static void __exit gigaset_exit_module(void)
{
+ gigaset_isdn_unregdrv();
}

module_init(gigaset_init_module);
diff --git a/drivers/isdn/gigaset/gigaset.h b/drivers/isdn/gigaset/gigaset.h
index 1875ab8..cdd144e 100644
--- a/drivers/isdn/gigaset/gigaset.h
+++ b/drivers/isdn/gigaset/gigaset.h
@@ -675,8 +675,10 @@ int gigaset_isowbuf_getbytes(struct isowbuf_t *iwb, int size);
*/

/* Called from common.c for setting up/shutting down with the ISDN subsystem */
-int gigaset_isdn_register(struct cardstate *cs, const char *isdnid);
-void gigaset_isdn_unregister(struct cardstate *cs);
+void gigaset_isdn_regdrv(void);
+void gigaset_isdn_unregdrv(void);
+int gigaset_isdn_regdev(struct cardstate *cs, const char *isdnid);
+void gigaset_isdn_unregdev(struct cardstate *cs);

/* Called from hardware module to indicate completion of an skb */
void gigaset_skb_sent(struct bc_state *bcs, struct sk_buff *skb);
diff --git a/drivers/isdn/gigaset/i4l.c b/drivers/isdn/gigaset/i4l.c
index f0acb9d..c22e5ac 100644
--- a/drivers/isdn/gigaset/i4l.c
+++ b/drivers/isdn/gigaset/i4l.c
@@ -592,15 +592,13 @@ void gigaset_isdn_stop(struct cardstate *cs)
}

/**
- * gigaset_isdn_register() - register to LL
+ * gigaset_isdn_regdev() - register to LL
* @cs: device descriptor structure.
* @isdnid: device name.
*
- * Called by main module to register the device with the LL.
- *
* Return value: 1 for success, 0 for failure
*/
-int gigaset_isdn_register(struct cardstate *cs, const char *isdnid)
+int gigaset_isdn_regdev(struct cardstate *cs, const char *isdnid)
{
isdn_if *iif;

@@ -650,15 +648,29 @@ int gigaset_isdn_register(struct cardstate *cs, const char *isdnid)
}

/**
- * gigaset_isdn_unregister() - unregister from LL
+ * gigaset_isdn_unregdev() - unregister device from LL
* @cs: device descriptor structure.
- *
- * Called by main module to unregister the device from the LL.
*/
-void gigaset_isdn_unregister(struct cardstate *cs)
+void gigaset_isdn_unregdev(struct cardstate *cs)
{
gig_dbg(DEBUG_CMD, "sending UNLOAD");
gigaset_i4l_cmd(cs, ISDN_STAT_UNLOAD);
kfree(cs->iif);
cs->iif = NULL;
}
+
+/**
+ * gigaset_isdn_regdrv() - register driver to LL
+ */
+void gigaset_isdn_regdrv(void)
+{
+ /* nothing to do */
+}
+
+/**
+ * gigaset_isdn_unregdrv() - unregister driver from LL
+ */
+void gigaset_isdn_unregdrv(void)
+{
+ /* nothing to do */
+}
--
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