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Revision 6f66cbc63081fd70e3191b4dbb796746780e5ae1 authored by Hugh Dickins on 14 April 2009, 18:25:42 UTC, committed by Linus Torvalds on 14 April 2009, 18:45:59 UTC 
x86 microcode: revert some work_on_cpu
 
Revert part of af5c820a3169e81af869c113e18ec7588836cd50 ("x86: cpumask:
use work_on_cpu in arch/x86/kernel/microcode_core.c")

That change is causing only one Intel CPU's microcode to be updated e.g.
microcode: CPU3 updated from revision 0x9 to 0x17, date = 2005-04-22
where before it announced that also for CPU0 and CPU1 and CPU2.

We cannot use work_on_cpu() in the CONFIG_MICROCODE_OLD_INTERFACE code,
because Intel's request_microcode_user() involves a copy_from_user() from
/sbin/microcode_ctl, which therefore needs to be on that CPU at the time.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 610f26e
Raw File
rwsem.c 
/* kernel/rwsem.c: R/W semaphores, public implementation
 *
 * Written by David Howells (dhowells@redhat.com).
 * Derived from asm-i386/semaphore.h
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/rwsem.h>

#include <asm/system.h>
#include <asm/atomic.h>

/*
 * lock for reading
 */
void __sched down_read(struct rw_semaphore *sem)
{
	might_sleep();
	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}

EXPORT_SYMBOL(down_read);

/*
 * trylock for reading -- returns 1 if successful, 0 if contention
 */
int down_read_trylock(struct rw_semaphore *sem)
{
	int ret = __down_read_trylock(sem);

	if (ret == 1)
		rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
	return ret;
}

EXPORT_SYMBOL(down_read_trylock);

/*
 * lock for writing
 */
void __sched down_write(struct rw_semaphore *sem)
{
	might_sleep();
	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
}

EXPORT_SYMBOL(down_write);

/*
 * trylock for writing -- returns 1 if successful, 0 if contention
 */
int down_write_trylock(struct rw_semaphore *sem)
{
	int ret = __down_write_trylock(sem);

	if (ret == 1)
		rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
	return ret;
}

EXPORT_SYMBOL(down_write_trylock);

/*
 * release a read lock
 */
void up_read(struct rw_semaphore *sem)
{
	rwsem_release(&sem->dep_map, 1, _RET_IP_);

	__up_read(sem);
}

EXPORT_SYMBOL(up_read);

/*
 * release a write lock
 */
void up_write(struct rw_semaphore *sem)
{
	rwsem_release(&sem->dep_map, 1, _RET_IP_);

	__up_write(sem);
}

EXPORT_SYMBOL(up_write);

/*
 * downgrade write lock to read lock
 */
void downgrade_write(struct rw_semaphore *sem)
{
	/*
	 * lockdep: a downgraded write will live on as a write
	 * dependency.
	 */
	__downgrade_write(sem);
}

EXPORT_SYMBOL(downgrade_write);

#ifdef CONFIG_DEBUG_LOCK_ALLOC

void down_read_nested(struct rw_semaphore *sem, int subclass)
{
	might_sleep();
	rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}

EXPORT_SYMBOL(down_read_nested);

void down_read_non_owner(struct rw_semaphore *sem)
{
	might_sleep();

	__down_read(sem);
}

EXPORT_SYMBOL(down_read_non_owner);

void down_write_nested(struct rw_semaphore *sem, int subclass)
{
	might_sleep();
	rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
}

EXPORT_SYMBOL(down_write_nested);

void up_read_non_owner(struct rw_semaphore *sem)
{
	__up_read(sem);
}

EXPORT_SYMBOL(up_read_non_owner);

#endif
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