diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/net/irda/sir_dongle.c |
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 @@ | |||
1 | /********************************************************************* | ||
2 | * | ||
3 | * sir_dongle.c: manager for serial dongle protocol drivers | ||
4 | * | ||
5 | * Copyright (c) 2002 Martin Diehl | ||
6 | * | ||
7 | * This program is free software; you can redistribute it and/or | ||
8 | * modify it under the terms of the GNU General Public License as | ||
9 | * published by the Free Software Foundation; either version 2 of | ||
10 | * the License, or (at your option) any later version. | ||
11 | * | ||
12 | ********************************************************************/ | ||
13 | |||
14 | #include <linux/module.h> | ||
15 | #include <linux/kernel.h> | ||
16 | #include <linux/init.h> | ||
17 | #include <linux/smp_lock.h> | ||
18 | #include <linux/kmod.h> | ||
19 | |||
20 | #include <net/irda/irda.h> | ||
21 | |||
22 | #include "sir-dev.h" | ||
23 | |||
24 | /************************************************************************** | ||
25 | * | ||
26 | * dongle registration and attachment | ||
27 | * | ||
28 | */ | ||
29 | |||
30 | static LIST_HEAD(dongle_list); /* list of registered dongle drivers */ | ||
31 | static DECLARE_MUTEX(dongle_list_lock); /* protects the list */ | ||
32 | |||
33 | int irda_register_dongle(struct dongle_driver *new) | ||
34 | { | ||
35 | struct list_head *entry; | ||
36 | struct dongle_driver *drv; | ||
37 | |||
38 | IRDA_DEBUG(0, "%s : registering dongle \"%s\" (%d).\n", | ||
39 | __FUNCTION__, new->driver_name, new->type); | ||
40 | |||
41 | down(&dongle_list_lock); | ||
42 | list_for_each(entry, &dongle_list) { | ||
43 | drv = list_entry(entry, struct dongle_driver, dongle_list); | ||
44 | if (new->type == drv->type) { | ||
45 | up(&dongle_list_lock); | ||
46 | return -EEXIST; | ||
47 | } | ||
48 | } | ||
49 | list_add(&new->dongle_list, &dongle_list); | ||
50 | up(&dongle_list_lock); | ||
51 | return 0; | ||
52 | } | ||
53 | |||
54 | int irda_unregister_dongle(struct dongle_driver *drv) | ||
55 | { | ||
56 | down(&dongle_list_lock); | ||
57 | list_del(&drv->dongle_list); | ||
58 | up(&dongle_list_lock); | ||
59 | return 0; | ||
60 | } | ||
61 | |||
62 | int sirdev_get_dongle(struct sir_dev *dev, IRDA_DONGLE type) | ||
63 | { | ||
64 | struct list_head *entry; | ||
65 | const struct dongle_driver *drv = NULL; | ||
66 | int err = -EINVAL; | ||
67 | |||
68 | #ifdef CONFIG_KMOD | ||
69 | request_module("irda-dongle-%d", type); | ||
70 | #endif | ||
71 | |||
72 | if (dev->dongle_drv != NULL) | ||
73 | return -EBUSY; | ||
74 | |||
75 | /* serialize access to the list of registered dongles */ | ||
76 | down(&dongle_list_lock); | ||
77 | |||
78 | list_for_each(entry, &dongle_list) { | ||
79 | drv = list_entry(entry, struct dongle_driver, dongle_list); | ||
80 | if (drv->type == type) | ||
81 | break; | ||
82 | else | ||
83 | drv = NULL; | ||
84 | } | ||
85 | |||
86 | if (!drv) { | ||
87 | err = -ENODEV; | ||
88 | goto out_unlock; /* no such dongle */ | ||
89 | } | ||
90 | |||
91 | /* handling of SMP races with dongle module removal - three cases: | ||
92 | * 1) dongle driver was already unregistered - then we haven't found the | ||
93 | * requested dongle above and are already out here | ||
94 | * 2) the module is already marked deleted but the driver is still | ||
95 | * registered - then the try_module_get() below will fail | ||
96 | * 3) the try_module_get() below succeeds before the module is marked | ||
97 | * deleted - then sys_delete_module() fails and prevents the removal | ||
98 | * because the module is in use. | ||
99 | */ | ||
100 | |||
101 | if (!try_module_get(drv->owner)) { | ||
102 | err = -ESTALE; | ||
103 | goto out_unlock; /* rmmod already pending */ | ||
104 | } | ||
105 | dev->dongle_drv = drv; | ||
106 | |||
107 | if (!drv->open || (err=drv->open(dev))!=0) | ||
108 | goto out_reject; /* failed to open driver */ | ||
109 | |||
110 | up(&dongle_list_lock); | ||
111 | return 0; | ||
112 | |||
113 | out_reject: | ||
114 | dev->dongle_drv = NULL; | ||
115 | module_put(drv->owner); | ||
116 | out_unlock: | ||
117 | up(&dongle_list_lock); | ||
118 | return err; | ||
119 | } | ||
120 | |||
121 | int sirdev_put_dongle(struct sir_dev *dev) | ||
122 | { | ||
123 | const struct dongle_driver *drv = dev->dongle_drv; | ||
124 | |||
125 | if (drv) { | ||
126 | if (drv->close) | ||
127 | drv->close(dev); /* close this dongle instance */ | ||
128 | |||
129 | dev->dongle_drv = NULL; /* unlink the dongle driver */ | ||
130 | module_put(drv->owner);/* decrement driver's module refcount */ | ||
131 | } | ||
132 | |||
133 | return 0; | ||
134 | } | ||