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authorMaciej Sosnowski <maciej.sosnowski@intel.com>2009-02-03 02:26:57 -0500
committerDavid S. Miller <davem@davemloft.net>2009-02-03 02:26:57 -0500
commiteb4400e3a040b90a3ad805b01fcbc99a5f615c8f (patch)
tree07c71314d189e5d0688d97f1cd2b3b504eb4892b /drivers
parentff01b9163655ace76b29b7ff2f56b25c32f795da (diff)
dca: redesign locks to fix deadlocks
Change spin_locks to irqsave to prevent dead-locks. Protect adding and deleting to/from dca_providers list. Drop the lock during dca_sysfs_add_req() and dca_sysfs_remove_req() calls as they might sleep (use GFP_KERNEL allocation). Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/dca/dca-core.c51
1 files changed, 33 insertions, 18 deletions
diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c
index 55433849bfa6..33bd75347518 100644
--- a/drivers/dca/dca-core.c
+++ b/drivers/dca/dca-core.c
@@ -28,7 +28,7 @@
28#include <linux/device.h> 28#include <linux/device.h>
29#include <linux/dca.h> 29#include <linux/dca.h>
30 30
31#define DCA_VERSION "1.4" 31#define DCA_VERSION "1.8"
32 32
33MODULE_VERSION(DCA_VERSION); 33MODULE_VERSION(DCA_VERSION);
34MODULE_LICENSE("GPL"); 34MODULE_LICENSE("GPL");
@@ -60,16 +60,17 @@ int dca_add_requester(struct device *dev)
60{ 60{
61 struct dca_provider *dca; 61 struct dca_provider *dca;
62 int err, slot = -ENODEV; 62 int err, slot = -ENODEV;
63 unsigned long flags;
63 64
64 if (!dev) 65 if (!dev)
65 return -EFAULT; 66 return -EFAULT;
66 67
67 spin_lock(&dca_lock); 68 spin_lock_irqsave(&dca_lock, flags);
68 69
69 /* check if the requester has not been added already */ 70 /* check if the requester has not been added already */
70 dca = dca_find_provider_by_dev(dev); 71 dca = dca_find_provider_by_dev(dev);
71 if (dca) { 72 if (dca) {
72 spin_unlock(&dca_lock); 73 spin_unlock_irqrestore(&dca_lock, flags);
73 return -EEXIST; 74 return -EEXIST;
74 } 75 }
75 76
@@ -78,19 +79,21 @@ int dca_add_requester(struct device *dev)
78 if (slot >= 0) 79 if (slot >= 0)
79 break; 80 break;
80 } 81 }
81 if (slot < 0) { 82
82 spin_unlock(&dca_lock); 83 spin_unlock_irqrestore(&dca_lock, flags);
84
85 if (slot < 0)
83 return slot; 86 return slot;
84 }
85 87
86 err = dca_sysfs_add_req(dca, dev, slot); 88 err = dca_sysfs_add_req(dca, dev, slot);
87 if (err) { 89 if (err) {
88 dca->ops->remove_requester(dca, dev); 90 spin_lock_irqsave(&dca_lock, flags);
89 spin_unlock(&dca_lock); 91 if (dca == dca_find_provider_by_dev(dev))
92 dca->ops->remove_requester(dca, dev);
93 spin_unlock_irqrestore(&dca_lock, flags);
90 return err; 94 return err;
91 } 95 }
92 96
93 spin_unlock(&dca_lock);
94 return 0; 97 return 0;
95} 98}
96EXPORT_SYMBOL_GPL(dca_add_requester); 99EXPORT_SYMBOL_GPL(dca_add_requester);
@@ -103,25 +106,25 @@ int dca_remove_requester(struct device *dev)
103{ 106{
104 struct dca_provider *dca; 107 struct dca_provider *dca;
105 int slot; 108 int slot;
109 unsigned long flags;
106 110
107 if (!dev) 111 if (!dev)
108 return -EFAULT; 112 return -EFAULT;
109 113
110 spin_lock(&dca_lock); 114 spin_lock_irqsave(&dca_lock, flags);
111 dca = dca_find_provider_by_dev(dev); 115 dca = dca_find_provider_by_dev(dev);
112 if (!dca) { 116 if (!dca) {
113 spin_unlock(&dca_lock); 117 spin_unlock_irqrestore(&dca_lock, flags);
114 return -ENODEV; 118 return -ENODEV;
115 } 119 }
116 slot = dca->ops->remove_requester(dca, dev); 120 slot = dca->ops->remove_requester(dca, dev);
117 if (slot < 0) { 121 spin_unlock_irqrestore(&dca_lock, flags);
118 spin_unlock(&dca_lock); 122
123 if (slot < 0)
119 return slot; 124 return slot;
120 }
121 125
122 dca_sysfs_remove_req(dca, slot); 126 dca_sysfs_remove_req(dca, slot);
123 127
124 spin_unlock(&dca_lock);
125 return 0; 128 return 0;
126} 129}
127EXPORT_SYMBOL_GPL(dca_remove_requester); 130EXPORT_SYMBOL_GPL(dca_remove_requester);
@@ -135,17 +138,18 @@ u8 dca_common_get_tag(struct device *dev, int cpu)
135{ 138{
136 struct dca_provider *dca; 139 struct dca_provider *dca;
137 u8 tag; 140 u8 tag;
141 unsigned long flags;
138 142
139 spin_lock(&dca_lock); 143 spin_lock_irqsave(&dca_lock, flags);
140 144
141 dca = dca_find_provider_by_dev(dev); 145 dca = dca_find_provider_by_dev(dev);
142 if (!dca) { 146 if (!dca) {
143 spin_unlock(&dca_lock); 147 spin_unlock_irqrestore(&dca_lock, flags);
144 return -ENODEV; 148 return -ENODEV;
145 } 149 }
146 tag = dca->ops->get_tag(dca, dev, cpu); 150 tag = dca->ops->get_tag(dca, dev, cpu);
147 151
148 spin_unlock(&dca_lock); 152 spin_unlock_irqrestore(&dca_lock, flags);
149 return tag; 153 return tag;
150} 154}
151 155
@@ -217,11 +221,16 @@ static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
217int register_dca_provider(struct dca_provider *dca, struct device *dev) 221int register_dca_provider(struct dca_provider *dca, struct device *dev)
218{ 222{
219 int err; 223 int err;
224 unsigned long flags;
220 225
221 err = dca_sysfs_add_provider(dca, dev); 226 err = dca_sysfs_add_provider(dca, dev);
222 if (err) 227 if (err)
223 return err; 228 return err;
229
230 spin_lock_irqsave(&dca_lock, flags);
224 list_add(&dca->node, &dca_providers); 231 list_add(&dca->node, &dca_providers);
232 spin_unlock_irqrestore(&dca_lock, flags);
233
225 blocking_notifier_call_chain(&dca_provider_chain, 234 blocking_notifier_call_chain(&dca_provider_chain,
226 DCA_PROVIDER_ADD, NULL); 235 DCA_PROVIDER_ADD, NULL);
227 return 0; 236 return 0;
@@ -234,9 +243,15 @@ EXPORT_SYMBOL_GPL(register_dca_provider);
234 */ 243 */
235void unregister_dca_provider(struct dca_provider *dca) 244void unregister_dca_provider(struct dca_provider *dca)
236{ 245{
246 unsigned long flags;
247
237 blocking_notifier_call_chain(&dca_provider_chain, 248 blocking_notifier_call_chain(&dca_provider_chain,
238 DCA_PROVIDER_REMOVE, NULL); 249 DCA_PROVIDER_REMOVE, NULL);
250
251 spin_lock_irqsave(&dca_lock, flags);
239 list_del(&dca->node); 252 list_del(&dca->node);
253 spin_unlock_irqrestore(&dca_lock, flags);
254
240 dca_sysfs_remove_provider(dca); 255 dca_sysfs_remove_provider(dca);
241} 256}
242EXPORT_SYMBOL_GPL(unregister_dca_provider); 257EXPORT_SYMBOL_GPL(unregister_dca_provider);