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authorRafael J. Wysocki <rjw@sisk.pl>2011-07-06 20:44:25 +0200
committerLen Brown <len.brown@intel.com>2011-07-13 14:49:09 -0400
commit07e49a7a31153a95caa270d8ad7350a0bcd4d511 (patch)
tree6a3fd7777be85069bcc44177b2348f7f618d4a47 /include/acpi
parent8d86e5f91440aa56a5df516bf58fe3883552ad56 (diff)
ACPI: Fix lockdep false positives in acpi_power_off()
All ACPICA locks are allocated by the same function, acpi_os_create_lock(), with the help of a local variable called "lock". Thus, when lockdep is enabled, it uses "lock" as the name of all those locks and regards them as instances of the same lock, which causes it to report possible locking problems with them when there aren't any. To work around this problem, define acpi_os_create_lock() as a macro and make it pass its argument to spin_lock_init(), so that lockdep uses it as the name of the new lock. Define this macron in a Linux-specific file, to minimize the resulting modifications of the OS-independent ACPICA parts. This change is based on an earlier patch from Andrea Righi and it addresses a regression from 2.6.39 tracked as https://bugzilla.kernel.org/show_bug.cgi?id=38152 Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reported-and-tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Andrea Righi <andrea@betterlinux.com> Reviewed-by: Florian Mickler <florian@mickler.org> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'include/acpi')
-rw-r--r--include/acpi/acpiosxf.h3
-rw-r--r--include/acpi/platform/aclinux.h18
2 files changed, 21 insertions, 0 deletions
diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h
index a756bc8d866..4543b6f7586 100644
--- a/include/acpi/acpiosxf.h
+++ b/include/acpi/acpiosxf.h
@@ -98,8 +98,11 @@ acpi_os_table_override(struct acpi_table_header *existing_table,
/*
* Spinlock primitives
*/
+
+#ifndef acpi_os_create_lock
acpi_status
acpi_os_create_lock(acpi_spinlock *out_handle);
+#endif
void acpi_os_delete_lock(acpi_spinlock handle);
diff --git a/include/acpi/platform/aclinux.h b/include/acpi/platform/aclinux.h
index 5d2a5e9544d..2ce1be9f629 100644
--- a/include/acpi/platform/aclinux.h
+++ b/include/acpi/platform/aclinux.h
@@ -159,6 +159,24 @@ static inline void *acpi_os_acquire_object(acpi_cache_t * cache)
} while (0)
#endif
+/*
+ * When lockdep is enabled, the spin_lock_init() macro stringifies it's
+ * argument and uses that as a name for the lock in debugging.
+ * By executing spin_lock_init() in a macro the key changes from "lock" for
+ * all locks to the name of the argument of acpi_os_create_lock(), which
+ * prevents lockdep from reporting false positives for ACPICA locks.
+ */
+#define acpi_os_create_lock(__handle) \
+({ \
+ spinlock_t *lock = ACPI_ALLOCATE(sizeof(*lock)); \
+ \
+ if (lock) { \
+ *(__handle) = lock; \
+ spin_lock_init(*(__handle)); \
+ } \
+ lock ? AE_OK : AE_NO_MEMORY; \
+})
+
#endif /* __KERNEL__ */
#endif /* __ACLINUX_H__ */