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Date: Wed, 13 Feb 2013 18:21:59 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: John Kacur <jkacur@...hat.com>
cc: Steven Rostedt <rostedt@...dmis.org>,
LKML <linux-kernel@...r.kernel.org>,
RT <linux-rt-users@...r.kernel.org>,
John Kacur <jkacur@...il.com>,
Clark Williams <clark@...hat.com>
Subject: Re: [RFC][PATCH RT] acpi/rt: Convert acpi lock back to a
raw_spinlock_t
On Wed, 13 Feb 2013, John Kacur wrote:
>
> Thanks Steven. That looks way better than the previous revert.
I can't tell as I haven't seen the previous revert. And looks good is
not really a good review criteria.
The patch is converting _all_ the spin_locks in acpi to raw spinlocks,
which will give you a nice bunch of "BUG: sleeping function called
from invalid context" splats depending on the ACPI functionality of
your machine.
The lock which is related to this splat is: acpi_gbl_hardware_lock and
that's the only lock which can be safely converted to a raw spinlock.
Untested patch below.
Thanks,
tglx
Index: linux-stable/drivers/acpi/acpica/acglobal.h
===================================================================
--- linux-stable.orig/drivers/acpi/acpica/acglobal.h
+++ linux-stable/drivers/acpi/acpica/acglobal.h
@@ -251,7 +251,7 @@ ACPI_EXTERN u8 acpi_gbl_global_lock_pend
* interrupt level
*/
ACPI_EXTERN acpi_spinlock acpi_gbl_gpe_lock; /* For GPE data structs and registers */
-ACPI_EXTERN acpi_spinlock acpi_gbl_hardware_lock; /* For ACPI H/W except GPE registers */
+ACPI_EXTERN acpi_raw_spinlock acpi_gbl_hardware_lock; /* For ACPI H/W except GPE registers */
/*****************************************************************************
*
Index: linux-stable/drivers/acpi/acpica/hwregs.c
===================================================================
--- linux-stable.orig/drivers/acpi/acpica/hwregs.c
+++ linux-stable/drivers/acpi/acpica/hwregs.c
@@ -271,14 +271,14 @@ acpi_status acpi_hw_clear_acpi_status(vo
ACPI_BITMASK_ALL_FIXED_STATUS,
ACPI_FORMAT_UINT64(acpi_gbl_xpm1a_status.address)));
- lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
+ raw_spin_lock_irqsave(acpi_gbl_hardware_lock, lock_flags);
/* Clear the fixed events in PM1 A/B */
status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
ACPI_BITMASK_ALL_FIXED_STATUS);
- acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
+ raw_spin_unlock_irqrestore(acpi_gbl_hardware_lock, lock_flags);
if (ACPI_FAILURE(status))
goto exit;
Index: linux-stable/drivers/acpi/acpica/hwxface.c
===================================================================
--- linux-stable.orig/drivers/acpi/acpica/hwxface.c
+++ linux-stable/drivers/acpi/acpica/hwxface.c
@@ -366,7 +366,7 @@ acpi_status acpi_write_bit_register(u32
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
- lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
+ raw_spin_lock_irqsave(acpi_gbl_hardware_lock, lock_flags);
/*
* At this point, we know that the parent register is one of the
@@ -427,7 +427,7 @@ acpi_status acpi_write_bit_register(u32
unlock_and_exit:
- acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
+ raw_spin_unlock_irqrestore(acpi_gbl_hardware_lock, lock_flags);
return_ACPI_STATUS(status);
}
Index: linux-stable/drivers/acpi/acpica/utmutex.c
===================================================================
--- linux-stable.orig/drivers/acpi/acpica/utmutex.c
+++ linux-stable/drivers/acpi/acpica/utmutex.c
@@ -88,7 +88,7 @@ acpi_status acpi_ut_mutex_initialize(voi
return_ACPI_STATUS (status);
}
- status = acpi_os_create_lock (&acpi_gbl_hardware_lock);
+ status = acpi_os_create_raw_lock (&acpi_gbl_hardware_lock);
if (ACPI_FAILURE (status)) {
return_ACPI_STATUS (status);
}
@@ -135,7 +135,7 @@ void acpi_ut_mutex_terminate(void)
/* Delete the spinlocks */
acpi_os_delete_lock(acpi_gbl_gpe_lock);
- acpi_os_delete_lock(acpi_gbl_hardware_lock);
+ acpi_os_delete_raw_lock(acpi_gbl_hardware_lock);
/* Delete the reader/writer lock */
Index: linux-stable/include/acpi/platform/aclinux.h
===================================================================
--- linux-stable.orig/include/acpi/platform/aclinux.h
+++ linux-stable/include/acpi/platform/aclinux.h
@@ -72,6 +72,7 @@
#define acpi_cache_t struct kmem_cache
#define acpi_spinlock spinlock_t *
+#define acpi_raw_spinlock raw_spinlock_t *
#define acpi_cpu_flags unsigned long
#else /* !__KERNEL__ */
@@ -175,6 +176,19 @@ static inline void *acpi_os_acquire_obje
lock ? AE_OK : AE_NO_MEMORY; \
})
+#define acpi_os_create_raw_lock(__handle) \
+({ \
+ raw_spinlock_t *lock = ACPI_ALLOCATE(sizeof(*lock)); \
+ \
+ if (lock) { \
+ *(__handle) = lock; \
+ raw_spin_lock_init(*(__handle)); \
+ } \
+ lock ? AE_OK : AE_NO_MEMORY; \
+})
+
+#define acpi_os_delete_raw_lock(__handle) kfree(__handle)
+
#endif /* __KERNEL__ */
#endif /* __ACLINUX_H__ */
--
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