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Commit 094e47e9fa79e28f0e51e37400ea6eea35a4ee1f

Authored by Hiroshi DOYU
Committed by Greg Kroah-Hartman
1 parent 3ce9a7c0ac
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

Driver Core: don't oops with unregistered driver in driver_find_device() 

driver_find_device() can be called with an unregistered driver. Need
to check driver_private to see if it's populated or not, especially
under deferrable probe.

In the case that there are 2 drivers, one depends on the other. With
-EPROBE_DEFER, two drivers can use deferred probe to ensure that their
relative probe order doesn't matter. If dependee driver is probed
first, then the dependant's driver_find_device('dependee')
succeeds. If the dependant is probed first, then the dependant's
driver_find_device('dependee') should return NULL, and the dependant
should get -EPROBE_DEFER. driver_find_device() needs to return NULL if
it's not populated.

In [PATCHv5 2/3] ARM: tegra: Add SMMU enabler in AHB:
  http://article.gmane.org/gmane.linux.ports.tegra/4658

"tegra_ahb_driver" may not be populated when it's called.

For more SMMU/AHB specific discussion, refer to the following thread:
  https://lkml.org/lkml/2012/5/10/21

Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 1 additions and 1 deletions Inline Diff

drivers/base/driver.c
Diff comments   View file @ 094e47e
1 /* 1 /*
2 * driver.c - centralized device driver management 2 * driver.c - centralized device driver management
3 * 3 *
4 * Copyright (c) 2002-3 Patrick Mochel 4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs 5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> 6 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2007 Novell Inc. 7 * Copyright (c) 2007 Novell Inc.
8 * 8 *
9 * This file is released under the GPLv2 9 * This file is released under the GPLv2
10 * 10 *
11 */ 11 */
12 12
13 #include <linux/device.h> 13 #include <linux/device.h>
14 #include <linux/module.h> 14 #include <linux/module.h>
15 #include <linux/errno.h> 15 #include <linux/errno.h>
16 #include <linux/slab.h> 16 #include <linux/slab.h>
17 #include <linux/string.h> 17 #include <linux/string.h>
18 #include "base.h" 18 #include "base.h"
19 19
20 static struct device *next_device(struct klist_iter *i) 20 static struct device *next_device(struct klist_iter *i)
21 { 21 {
22 struct klist_node *n = klist_next(i); 22 struct klist_node *n = klist_next(i);
23 struct device *dev = NULL; 23 struct device *dev = NULL;
24 struct device_private *dev_prv; 24 struct device_private *dev_prv;
25 25
26 if (n) { 26 if (n) {
27 dev_prv = to_device_private_driver(n); 27 dev_prv = to_device_private_driver(n);
28 dev = dev_prv->device; 28 dev = dev_prv->device;
29 } 29 }
30 return dev; 30 return dev;
31 } 31 }
32 32
33 /** 33 /**
34 * driver_for_each_device - Iterator for devices bound to a driver. 34 * driver_for_each_device - Iterator for devices bound to a driver.
35 * @drv: Driver we're iterating. 35 * @drv: Driver we're iterating.
36 * @start: Device to begin with 36 * @start: Device to begin with
37 * @data: Data to pass to the callback. 37 * @data: Data to pass to the callback.
38 * @fn: Function to call for each device. 38 * @fn: Function to call for each device.
39 * 39 *
40 * Iterate over the @drv's list of devices calling @fn for each one. 40 * Iterate over the @drv's list of devices calling @fn for each one.
41 */ 41 */
42 int driver_for_each_device(struct device_driver *drv, struct device *start, 42 int driver_for_each_device(struct device_driver *drv, struct device *start,
43 void *data, int (*fn)(struct device *, void *)) 43 void *data, int (*fn)(struct device *, void *))
44 { 44 {
45 struct klist_iter i; 45 struct klist_iter i;
46 struct device *dev; 46 struct device *dev;
47 int error = 0; 47 int error = 0;
48 48
49 if (!drv) 49 if (!drv)
50 return -EINVAL; 50 return -EINVAL;
51 51
52 klist_iter_init_node(&drv->p->klist_devices, &i, 52 klist_iter_init_node(&drv->p->klist_devices, &i,
53 start ? &start->p->knode_driver : NULL); 53 start ? &start->p->knode_driver : NULL);
54 while ((dev = next_device(&i)) && !error) 54 while ((dev = next_device(&i)) && !error)
55 error = fn(dev, data); 55 error = fn(dev, data);
56 klist_iter_exit(&i); 56 klist_iter_exit(&i);
57 return error; 57 return error;
58 } 58 }
59 EXPORT_SYMBOL_GPL(driver_for_each_device); 59 EXPORT_SYMBOL_GPL(driver_for_each_device);
60 60
61 /** 61 /**
62 * driver_find_device - device iterator for locating a particular device. 62 * driver_find_device - device iterator for locating a particular device.
63 * @drv: The device's driver 63 * @drv: The device's driver
64 * @start: Device to begin with 64 * @start: Device to begin with
65 * @data: Data to pass to match function 65 * @data: Data to pass to match function
66 * @match: Callback function to check device 66 * @match: Callback function to check device
67 * 67 *
68 * This is similar to the driver_for_each_device() function above, but 68 * This is similar to the driver_for_each_device() function above, but
69 * it returns a reference to a device that is 'found' for later use, as 69 * it returns a reference to a device that is 'found' for later use, as
70 * determined by the @match callback. 70 * determined by the @match callback.
71 * 71 *
72 * The callback should return 0 if the device doesn't match and non-zero 72 * The callback should return 0 if the device doesn't match and non-zero
73 * if it does. If the callback returns non-zero, this function will 73 * if it does. If the callback returns non-zero, this function will
74 * return to the caller and not iterate over any more devices. 74 * return to the caller and not iterate over any more devices.
75 */ 75 */
76 struct device *driver_find_device(struct device_driver *drv, 76 struct device *driver_find_device(struct device_driver *drv,
77 struct device *start, void *data, 77 struct device *start, void *data,
78 int (*match)(struct device *dev, void *data)) 78 int (*match)(struct device *dev, void *data))
79 { 79 {
80 struct klist_iter i; 80 struct klist_iter i;
81 struct device *dev; 81 struct device *dev;
82 82
83 if (!drv) 83 if (!drv || !drv->p)
84 return NULL; 84 return NULL;
85 85
86 klist_iter_init_node(&drv->p->klist_devices, &i, 86 klist_iter_init_node(&drv->p->klist_devices, &i,
87 (start ? &start->p->knode_driver : NULL)); 87 (start ? &start->p->knode_driver : NULL));
88 while ((dev = next_device(&i))) 88 while ((dev = next_device(&i)))
89 if (match(dev, data) && get_device(dev)) 89 if (match(dev, data) && get_device(dev))
90 break; 90 break;
91 klist_iter_exit(&i); 91 klist_iter_exit(&i);
92 return dev; 92 return dev;
93 } 93 }
94 EXPORT_SYMBOL_GPL(driver_find_device); 94 EXPORT_SYMBOL_GPL(driver_find_device);
95 95
96 /** 96 /**
97 * driver_create_file - create sysfs file for driver. 97 * driver_create_file - create sysfs file for driver.
98 * @drv: driver. 98 * @drv: driver.
99 * @attr: driver attribute descriptor. 99 * @attr: driver attribute descriptor.
100 */ 100 */
101 int driver_create_file(struct device_driver *drv, 101 int driver_create_file(struct device_driver *drv,
102 const struct driver_attribute *attr) 102 const struct driver_attribute *attr)
103 { 103 {
104 int error; 104 int error;
105 if (drv) 105 if (drv)
106 error = sysfs_create_file(&drv->p->kobj, &attr->attr); 106 error = sysfs_create_file(&drv->p->kobj, &attr->attr);
107 else 107 else
108 error = -EINVAL; 108 error = -EINVAL;
109 return error; 109 return error;
110 } 110 }
111 EXPORT_SYMBOL_GPL(driver_create_file); 111 EXPORT_SYMBOL_GPL(driver_create_file);
112 112
113 /** 113 /**
114 * driver_remove_file - remove sysfs file for driver. 114 * driver_remove_file - remove sysfs file for driver.
115 * @drv: driver. 115 * @drv: driver.
116 * @attr: driver attribute descriptor. 116 * @attr: driver attribute descriptor.
117 */ 117 */
118 void driver_remove_file(struct device_driver *drv, 118 void driver_remove_file(struct device_driver *drv,
119 const struct driver_attribute *attr) 119 const struct driver_attribute *attr)
120 { 120 {
121 if (drv) 121 if (drv)
122 sysfs_remove_file(&drv->p->kobj, &attr->attr); 122 sysfs_remove_file(&drv->p->kobj, &attr->attr);
123 } 123 }
124 EXPORT_SYMBOL_GPL(driver_remove_file); 124 EXPORT_SYMBOL_GPL(driver_remove_file);
125 125
126 static int driver_add_groups(struct device_driver *drv, 126 static int driver_add_groups(struct device_driver *drv,
127 const struct attribute_group **groups) 127 const struct attribute_group **groups)
128 { 128 {
129 int error = 0; 129 int error = 0;
130 int i; 130 int i;
131 131
132 if (groups) { 132 if (groups) {
133 for (i = 0; groups[i]; i++) { 133 for (i = 0; groups[i]; i++) {
134 error = sysfs_create_group(&drv->p->kobj, groups[i]); 134 error = sysfs_create_group(&drv->p->kobj, groups[i]);
135 if (error) { 135 if (error) {
136 while (--i >= 0) 136 while (--i >= 0)
137 sysfs_remove_group(&drv->p->kobj, 137 sysfs_remove_group(&drv->p->kobj,
138 groups[i]); 138 groups[i]);
139 break; 139 break;
140 } 140 }
141 } 141 }
142 } 142 }
143 return error; 143 return error;
144 } 144 }
145 145
146 static void driver_remove_groups(struct device_driver *drv, 146 static void driver_remove_groups(struct device_driver *drv,
147 const struct attribute_group **groups) 147 const struct attribute_group **groups)
148 { 148 {
149 int i; 149 int i;
150 150
151 if (groups) 151 if (groups)
152 for (i = 0; groups[i]; i++) 152 for (i = 0; groups[i]; i++)
153 sysfs_remove_group(&drv->p->kobj, groups[i]); 153 sysfs_remove_group(&drv->p->kobj, groups[i]);
154 } 154 }
155 155
156 /** 156 /**
157 * driver_register - register driver with bus 157 * driver_register - register driver with bus
158 * @drv: driver to register 158 * @drv: driver to register
159 * 159 *
160 * We pass off most of the work to the bus_add_driver() call, 160 * We pass off most of the work to the bus_add_driver() call,
161 * since most of the things we have to do deal with the bus 161 * since most of the things we have to do deal with the bus
162 * structures. 162 * structures.
163 */ 163 */
164 int driver_register(struct device_driver *drv) 164 int driver_register(struct device_driver *drv)
165 { 165 {
166 int ret; 166 int ret;
167 struct device_driver *other; 167 struct device_driver *other;
168 168
169 BUG_ON(!drv->bus->p); 169 BUG_ON(!drv->bus->p);
170 170
171 if ((drv->bus->probe && drv->probe) || 171 if ((drv->bus->probe && drv->probe) ||
172 (drv->bus->remove && drv->remove) || 172 (drv->bus->remove && drv->remove) ||
173 (drv->bus->shutdown && drv->shutdown)) 173 (drv->bus->shutdown && drv->shutdown))
174 printk(KERN_WARNING "Driver '%s' needs updating - please use " 174 printk(KERN_WARNING "Driver '%s' needs updating - please use "
175 "bus_type methods\n", drv->name); 175 "bus_type methods\n", drv->name);
176 176
177 other = driver_find(drv->name, drv->bus); 177 other = driver_find(drv->name, drv->bus);
178 if (other) { 178 if (other) {
179 printk(KERN_ERR "Error: Driver '%s' is already registered, " 179 printk(KERN_ERR "Error: Driver '%s' is already registered, "
180 "aborting...\n", drv->name); 180 "aborting...\n", drv->name);
181 return -EBUSY; 181 return -EBUSY;
182 } 182 }
183 183
184 ret = bus_add_driver(drv); 184 ret = bus_add_driver(drv);
185 if (ret) 185 if (ret)
186 return ret; 186 return ret;
187 ret = driver_add_groups(drv, drv->groups); 187 ret = driver_add_groups(drv, drv->groups);
188 if (ret) 188 if (ret)
189 bus_remove_driver(drv); 189 bus_remove_driver(drv);
190 return ret; 190 return ret;
191 } 191 }
192 EXPORT_SYMBOL_GPL(driver_register); 192 EXPORT_SYMBOL_GPL(driver_register);
193 193
194 /** 194 /**
195 * driver_unregister - remove driver from system. 195 * driver_unregister - remove driver from system.
196 * @drv: driver. 196 * @drv: driver.
197 * 197 *
198 * Again, we pass off most of the work to the bus-level call. 198 * Again, we pass off most of the work to the bus-level call.
199 */ 199 */
200 void driver_unregister(struct device_driver *drv) 200 void driver_unregister(struct device_driver *drv)
201 { 201 {
202 if (!drv || !drv->p) { 202 if (!drv || !drv->p) {
203 WARN(1, "Unexpected driver unregister!\n"); 203 WARN(1, "Unexpected driver unregister!\n");
204 return; 204 return;
205 } 205 }
206 driver_remove_groups(drv, drv->groups); 206 driver_remove_groups(drv, drv->groups);
207 bus_remove_driver(drv); 207 bus_remove_driver(drv);
208 } 208 }
209 EXPORT_SYMBOL_GPL(driver_unregister); 209 EXPORT_SYMBOL_GPL(driver_unregister);
210 210
211 /** 211 /**
212 * driver_find - locate driver on a bus by its name. 212 * driver_find - locate driver on a bus by its name.
213 * @name: name of the driver. 213 * @name: name of the driver.
214 * @bus: bus to scan for the driver. 214 * @bus: bus to scan for the driver.
215 * 215 *
216 * Call kset_find_obj() to iterate over list of drivers on 216 * Call kset_find_obj() to iterate over list of drivers on
217 * a bus to find driver by name. Return driver if found. 217 * a bus to find driver by name. Return driver if found.
218 * 218 *
219 * This routine provides no locking to prevent the driver it returns 219 * This routine provides no locking to prevent the driver it returns
220 * from being unregistered or unloaded while the caller is using it. 220 * from being unregistered or unloaded while the caller is using it.
221 * The caller is responsible for preventing this. 221 * The caller is responsible for preventing this.
222 */ 222 */
223 struct device_driver *driver_find(const char *name, struct bus_type *bus) 223 struct device_driver *driver_find(const char *name, struct bus_type *bus)
224 { 224 {
225 struct kobject *k = kset_find_obj(bus->p->drivers_kset, name); 225 struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
226 struct driver_private *priv; 226 struct driver_private *priv;
227 227
228 if (k) { 228 if (k) {
229 /* Drop reference added by kset_find_obj() */ 229 /* Drop reference added by kset_find_obj() */
230 kobject_put(k); 230 kobject_put(k);
231 priv = to_driver(k); 231 priv = to_driver(k);
232 return priv->driver; 232 return priv->driver;
233 } 233 }
234 return NULL; 234 return NULL;
235 } 235 }
236 EXPORT_SYMBOL_GPL(driver_find); 236 EXPORT_SYMBOL_GPL(driver_find);
237 237