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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/net/irda/sir_dongle.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/net/irda/sir_dongle.c')
-rw-r--r-- | drivers/net/irda/sir_dongle.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/drivers/net/irda/sir_dongle.c b/drivers/net/irda/sir_dongle.c new file mode 100644 index 000000000000..c5b76746e72b --- /dev/null +++ b/drivers/net/irda/sir_dongle.c @@ -0,0 +1,134 @@ +/********************************************************************* + * + * sir_dongle.c: manager for serial dongle protocol drivers + * + * Copyright (c) 2002 Martin Diehl + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + ********************************************************************/ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/smp_lock.h> +#include <linux/kmod.h> + +#include <net/irda/irda.h> + +#include "sir-dev.h" + +/************************************************************************** + * + * dongle registration and attachment + * + */ + +static LIST_HEAD(dongle_list); /* list of registered dongle drivers */ +static DECLARE_MUTEX(dongle_list_lock); /* protects the list */ + +int irda_register_dongle(struct dongle_driver *new) +{ + struct list_head *entry; + struct dongle_driver *drv; + + IRDA_DEBUG(0, "%s : registering dongle \"%s\" (%d).\n", + __FUNCTION__, new->driver_name, new->type); + + down(&dongle_list_lock); + list_for_each(entry, &dongle_list) { + drv = list_entry(entry, struct dongle_driver, dongle_list); + if (new->type == drv->type) { + up(&dongle_list_lock); + return -EEXIST; + } + } + list_add(&new->dongle_list, &dongle_list); + up(&dongle_list_lock); + return 0; +} + +int irda_unregister_dongle(struct dongle_driver *drv) +{ + down(&dongle_list_lock); + list_del(&drv->dongle_list); + up(&dongle_list_lock); + return 0; +} + +int sirdev_get_dongle(struct sir_dev *dev, IRDA_DONGLE type) +{ + struct list_head *entry; + const struct dongle_driver *drv = NULL; + int err = -EINVAL; + +#ifdef CONFIG_KMOD + request_module("irda-dongle-%d", type); +#endif + + if (dev->dongle_drv != NULL) + return -EBUSY; + + /* serialize access to the list of registered dongles */ + down(&dongle_list_lock); + + list_for_each(entry, &dongle_list) { + drv = list_entry(entry, struct dongle_driver, dongle_list); + if (drv->type == type) + break; + else + drv = NULL; + } + + if (!drv) { + err = -ENODEV; + goto out_unlock; /* no such dongle */ + } + + /* handling of SMP races with dongle module removal - three cases: + * 1) dongle driver was already unregistered - then we haven't found the + * requested dongle above and are already out here + * 2) the module is already marked deleted but the driver is still + * registered - then the try_module_get() below will fail + * 3) the try_module_get() below succeeds before the module is marked + * deleted - then sys_delete_module() fails and prevents the removal + * because the module is in use. + */ + + if (!try_module_get(drv->owner)) { + err = -ESTALE; + goto out_unlock; /* rmmod already pending */ + } + dev->dongle_drv = drv; + + if (!drv->open || (err=drv->open(dev))!=0) + goto out_reject; /* failed to open driver */ + + up(&dongle_list_lock); + return 0; + +out_reject: + dev->dongle_drv = NULL; + module_put(drv->owner); +out_unlock: + up(&dongle_list_lock); + return err; +} + +int sirdev_put_dongle(struct sir_dev *dev) +{ + const struct dongle_driver *drv = dev->dongle_drv; + + if (drv) { + if (drv->close) + drv->close(dev); /* close this dongle instance */ + + dev->dongle_drv = NULL; /* unlink the dongle driver */ + module_put(drv->owner);/* decrement driver's module refcount */ + } + + return 0; +} |