locking, drivers/dca: Annotate dca_lock as raw
The dca_lock can be taken in atomic context:
[ 25.607536] Call Trace:
[ 25.607557] [<ffffffff820078a1>] try_stack_unwind+0x151/0x1a0
[ 25.607566] [<ffffffff820062c2>] dump_trace+0x92/0x370
[ 25.607573] [<ffffffff8200731c>] show_trace_log_lvl+0x5c/0x80
[ 25.607578] [<ffffffff82007355>] show_trace+0x15/0x20
[ 25.607587] [<ffffffff823f4588>] dump_stack+0x77/0x8f
[ 25.607595] [<ffffffff82043f2a>] __might_sleep+0x11a/0x130
[ 25.607602] [<ffffffff823f7b93>] rt_spin_lock+0x83/0x90
[ 25.607611] [<ffffffffa0209138>] dca_common_get_tag+0x28/0x80 [dca]
[ 25.607622] [<ffffffffa02091c8>] dca3_get_tag+0x18/0x20 [dca]
[ 25.607634] [<ffffffffa0244e71>] igb_update_dca+0xb1/0x1d0 [igb]
[ 25.607649] [<ffffffffa0244ff5>] igb_setup_dca+0x65/0x80 [igb]
[ 25.607663] [<ffffffffa02535a6>] igb_probe+0x946/0xe4d [igb]
[ 25.607678] [<ffffffff82247517>] local_pci_probe+0x17/0x20
[ 25.607686] [<ffffffff82248661>] pci_device_probe+0x121/0x130
[ 25.607699] [<ffffffff822e4832>] driver_probe_device+0xd2/0x2e0
[ 25.607707] [<ffffffff822e4adb>] __driver_attach+0x9b/0xa0
[ 25.607714] [<ffffffff822e3d1b>] bus_for_each_dev+0x6b/0xa0
[ 25.607720] [<ffffffff822e4591>] driver_attach+0x21/0x30
[ 25.607727] [<ffffffff822e3425>] bus_add_driver+0x1e5/0x350
[ 25.607734] [<ffffffff822e4e41>] driver_register+0x81/0x160
[ 25.607742] [<ffffffff8224890f>] __pci_register_driver+0x6f/0xf0
[ 25.607752] [<ffffffffa011505b>] igb_init_module+0x5b/0x5d [igb]
[ 25.607769] [<ffffffff820001dd>] do_one_initcall+0x3d/0x1a0
[ 25.607778] [<ffffffff820961f6>] sys_init_module+0xe6/0x270
[ 25.607786] [<ffffffff82003232>] system_call_fastpath+0x16/0x1b
[ 25.607794] [<00007f84d6783f4a>] 0x7f84d6783f4a
and thus must not be preempted on -rt.
In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.
Signed-off-by: Mike Galbraith <efault@gmx.de>
[ Fixed the domain allocation which was calling kzalloc from the irq disabled section ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c
index 4abd089..25ec0bb 100644
--- a/drivers/dca/dca-core.c
+++ b/drivers/dca/dca-core.c
@@ -35,7 +35,7 @@
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Intel Corporation");
-static DEFINE_SPINLOCK(dca_lock);
+static DEFINE_RAW_SPINLOCK(dca_lock);
static LIST_HEAD(dca_domains);
@@ -101,10 +101,10 @@
INIT_LIST_HEAD(&unregistered_providers);
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
if (list_empty(&dca_domains)) {
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return;
}
@@ -116,7 +116,7 @@
dca_free_domain(domain);
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
dca_sysfs_remove_provider(dca);
@@ -144,13 +144,8 @@
domain = dca_find_domain(rc);
if (!domain) {
- if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) {
+ if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains))
dca_providers_blocked = 1;
- } else {
- domain = dca_allocate_domain(rc);
- if (domain)
- list_add(&domain->node, &dca_domains);
- }
}
return domain;
@@ -198,19 +193,19 @@
if (!dev)
return -EFAULT;
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
/* check if the requester has not been added already */
dca = dca_find_provider_by_dev(dev);
if (dca) {
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return -EEXIST;
}
pci_rc = dca_pci_rc_from_dev(dev);
domain = dca_find_domain(pci_rc);
if (!domain) {
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return -ENODEV;
}
@@ -220,17 +215,17 @@
break;
}
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
if (slot < 0)
return slot;
err = dca_sysfs_add_req(dca, dev, slot);
if (err) {
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
if (dca == dca_find_provider_by_dev(dev))
dca->ops->remove_requester(dca, dev);
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return err;
}
@@ -251,14 +246,14 @@
if (!dev)
return -EFAULT;
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
dca = dca_find_provider_by_dev(dev);
if (!dca) {
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return -ENODEV;
}
slot = dca->ops->remove_requester(dca, dev);
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
if (slot < 0)
return slot;
@@ -280,16 +275,16 @@
u8 tag;
unsigned long flags;
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
dca = dca_find_provider_by_dev(dev);
if (!dca) {
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return -ENODEV;
}
tag = dca->ops->get_tag(dca, dev, cpu);
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return tag;
}
@@ -360,36 +355,51 @@
{
int err;
unsigned long flags;
- struct dca_domain *domain;
+ struct dca_domain *domain, *newdomain = NULL;
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
if (dca_providers_blocked) {
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
return -ENODEV;
}
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
err = dca_sysfs_add_provider(dca, dev);
if (err)
return err;
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
domain = dca_get_domain(dev);
if (!domain) {
+ struct pci_bus *rc;
+
if (dca_providers_blocked) {
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
dca_sysfs_remove_provider(dca);
unregister_dca_providers();
- } else {
- spin_unlock_irqrestore(&dca_lock, flags);
+ return -ENODEV;
}
- return -ENODEV;
+
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
+ rc = dca_pci_rc_from_dev(dev);
+ newdomain = dca_allocate_domain(rc);
+ if (!newdomain)
+ return -ENODEV;
+ raw_spin_lock_irqsave(&dca_lock, flags);
+ /* Recheck, we might have raced after dropping the lock */
+ domain = dca_get_domain(dev);
+ if (!domain) {
+ domain = newdomain;
+ newdomain = NULL;
+ list_add(&domain->node, &dca_domains);
+ }
}
list_add(&dca->node, &domain->dca_providers);
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
blocking_notifier_call_chain(&dca_provider_chain,
DCA_PROVIDER_ADD, NULL);
+ kfree(newdomain);
return 0;
}
EXPORT_SYMBOL_GPL(register_dca_provider);
@@ -407,7 +417,7 @@
blocking_notifier_call_chain(&dca_provider_chain,
DCA_PROVIDER_REMOVE, NULL);
- spin_lock_irqsave(&dca_lock, flags);
+ raw_spin_lock_irqsave(&dca_lock, flags);
list_del(&dca->node);
@@ -416,7 +426,7 @@
if (list_empty(&domain->dca_providers))
dca_free_domain(domain);
- spin_unlock_irqrestore(&dca_lock, flags);
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
dca_sysfs_remove_provider(dca);
}