ChangeSet 1.1492.1.2, 2005/04/05 11:05:24-03:00, [EMAIL PROTECTED]
[PATCH] rwsem: Make rwsems use interrupt disabling spinlocks
# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
# 2005/03/09 10:25:02-08:00 [EMAIL PROTECTED]
# [PATCH] rwsem: Make rwsems use interrupt disabling spinlocks
#
# The attached patch makes read/write semaphores use interrupt
disabling
# spinlocks in the slow path, thus rendering the up functions and
trylock
# functions available for use in interrupt context. This matches the
# regular semaphore behaviour.
#
# I've assumed that the normal down functions must be called with
interrupts
# enabled (since they might schedule), and used the irq-disabling
spinlock
# variants that don't save the flags.
#
# Signed-Off-By: David Howells <[EMAIL PROTECTED]>
# Tested-by: Badari Pulavarty <[EMAIL PROTECTED]>
# Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
#
# lib/rwsem.c
# 2005/03/09 02:45:16-08:00 [EMAIL PROTECTED] +10 -6
# rwsem: Make rwsems use interrupt disabling spinlocks
#
# lib/rwsem-spinlock.c
# 2005/03/09 02:43:47-08:00 [EMAIL PROTECTED] +26 -16
# rwsem: Make rwsems use interrupt disabling spinlocks
#
rwsem-spinlock.c | 32 ++++++++++++++++++--------------
rwsem.c | 9 +++++----
2 files changed, 23 insertions(+), 18 deletions(-)
diff -Nru a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c
--- a/lib/rwsem-spinlock.c 2005-04-05 13:02:58 -07:00
+++ b/lib/rwsem-spinlock.c 2005-04-05 13:02:58 -07:00
@@ -127,12 +127,12 @@
rwsemtrace(sem,"Entering __down_read");
- spin_lock(&sem->wait_lock);
+ spin_lock_irq(&sem->wait_lock);
if (sem->activity>=0 && list_empty(&sem->wait_list)) {
/* granted */
sem->activity++;
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irq(&sem->wait_lock);
goto out;
}
@@ -147,7 +147,7 @@
list_add_tail(&waiter.list,&sem->wait_list);
/* we don't need to touch the semaphore struct anymore */
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irq(&sem->wait_lock);
/* wait to be given the lock */
for (;;) {
@@ -169,9 +169,10 @@
int fastcall __down_read_trylock(struct rw_semaphore *sem)
{
int ret = 0;
+ unsigned long flags;
rwsemtrace(sem,"Entering __down_read_trylock");
- spin_lock(&sem->wait_lock);
+ spin_lock_irqsave(&sem->wait_lock, flags);
if (sem->activity>=0 && list_empty(&sem->wait_list)) {
/* granted */
@@ -179,7 +180,7 @@
ret = 1;
}
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irqrestore(&sem->wait_lock, flags);
rwsemtrace(sem,"Leaving __down_read_trylock");
return ret;
@@ -196,12 +197,12 @@
rwsemtrace(sem,"Entering __down_write");
- spin_lock(&sem->wait_lock);
+ spin_lock_irq(&sem->wait_lock);
if (sem->activity==0 && list_empty(&sem->wait_list)) {
/* granted */
sem->activity = -1;
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irq(&sem->wait_lock);
goto out;
}
@@ -216,7 +217,7 @@
list_add_tail(&waiter.list,&sem->wait_list);
/* we don't need to touch the semaphore struct anymore */
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irq(&sem->wait_lock);
/* wait to be given the lock */
for (;;) {
@@ -238,9 +239,10 @@
int fastcall __down_write_trylock(struct rw_semaphore *sem)
{
int ret = 0;
+ unsigned long flags;
rwsemtrace(sem,"Entering __down_write_trylock");
- spin_lock(&sem->wait_lock);
+ spin_lock_irqsave(&sem->wait_lock, flags);
if (sem->activity==0 && list_empty(&sem->wait_list)) {
/* granted */
@@ -248,7 +250,7 @@
ret = 1;
}
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irqrestore(&sem->wait_lock, flags);
rwsemtrace(sem,"Leaving __down_write_trylock");
return ret;
@@ -259,14 +261,15 @@
*/
void fastcall __up_read(struct rw_semaphore *sem)
{
+ unsigned long flags;
rwsemtrace(sem,"Entering __up_read");
- spin_lock(&sem->wait_lock);
+ spin_lock_irqsave(&sem->wait_lock, flags);
if (--sem->activity==0 && !list_empty(&sem->wait_list))
sem = __rwsem_wake_one_writer(sem);
- spin_unlock(&sem->wait_lock);
+ spin_unlock_restore(&sem->wait_lock, flags);
rwsemtrace(sem,"Leaving __up_read");
}
@@ -276,15 +279,16 @@
*/
void fastcall __up_write(struct rw_semaphore *sem)
{
+ unsigned long flags;
rwsemtrace(sem,"Entering __up_write");
- spin_lock(&sem->wait_lock);
+ spin_lock_irqsave(&sem->wait_lock, flags);
sem->activity = 0;
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem);
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irqrestore(&sem->wait_lock, flags);
rwsemtrace(sem,"Leaving __up_write");
}
diff -Nru a/lib/rwsem.c b/lib/rwsem.c
--- a/lib/rwsem.c 2005-04-05 13:02:58 -07:00
+++ b/lib/rwsem.c 2005-04-05 13:02:58 -07:00
@@ -127,7 +127,7 @@
set_task_state(tsk,TASK_UNINTERRUPTIBLE);
/* set up my own style of waitqueue */
- spin_lock(&sem->wait_lock);
+ spin_lock_irq(&sem->wait_lock);
waiter->task = tsk;
get_task_struct(tsk);
@@ -142,7 +142,7 @@
if (!(count & RWSEM_ACTIVE_MASK))
sem = __rwsem_do_wake(sem);
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irq(&sem->wait_lock);
/* wait to be given the lock */
for (;;) {
@@ -195,15 +195,16 @@
*/
struct rw_semaphore fastcall *rwsem_wake(struct rw_semaphore *sem)
{
+ unsigned long flags;
rwsemtrace(sem,"Entering rwsem_wake");
- spin_lock(&sem->wait_lock);
+ spin_lock_irqsave(&sem->wait_lock, flags);
/* do nothing if list empty */
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem);
- spin_unlock(&sem->wait_lock);
+ spin_unlock_irqrestore(&sem->wait_lock, flags);
rwsemtrace(sem,"Leaving rwsem_wake");
-
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