diff options
| author | Kevin Hilman <khilman@deeprootsystems.com> | 2010-04-07 11:52:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-04-07 16:15:05 -0700 |
| commit | 3eac4abaa69949af0e2f64e5c55ee8a22bbdd3e7 (patch) | |
| tree | 9620ae3c39a0870a010a08166e29823a7afbf262 /lib/rwsem-spinlock.c | |
| parent | 04287f975e68038051eb9c79896866d36610b8e0 (diff) | |
| download | linux-rt-3eac4abaa69949af0e2f64e5c55ee8a22bbdd3e7.tar.gz | |
rwsem generic spinlock: use IRQ save/restore spinlocks
rwsems can be used with IRQs disabled, particularily in early boot
before IRQs are enabled. Currently the spin_unlock_irq() usage in the
slow-patch will unconditionally enable interrupts and cause problems
since interrupts are not yet initialized or enabled.
This patch uses save/restore versions of IRQ spinlocks in the slowpath
to ensure interrupts are not unintentionally disabled.
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/rwsem-spinlock.c')
| -rw-r--r-- | lib/rwsem-spinlock.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c index ccf95bff7984..ffc9fc7f3b05 100644 --- a/lib/rwsem-spinlock.c +++ b/lib/rwsem-spinlock.c @@ -143,13 +143,14 @@ void __sched __down_read(struct rw_semaphore *sem) { struct rwsem_waiter waiter; struct task_struct *tsk; + unsigned long flags; - spin_lock_irq(&sem->wait_lock); + spin_lock_irqsave(&sem->wait_lock, flags); if (sem->activity >= 0 && list_empty(&sem->wait_list)) { /* granted */ sem->activity++; - spin_unlock_irq(&sem->wait_lock); + spin_unlock_irqrestore(&sem->wait_lock, flags); goto out; } @@ -164,7 +165,7 @@ void __sched __down_read(struct rw_semaphore *sem) list_add_tail(&waiter.list, &sem->wait_list); /* we don't need to touch the semaphore struct anymore */ - spin_unlock_irq(&sem->wait_lock); + spin_unlock_irqrestore(&sem->wait_lock, flags); /* wait to be given the lock */ for (;;) { @@ -209,13 +210,14 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass) { struct rwsem_waiter waiter; struct task_struct *tsk; + unsigned long flags; - spin_lock_irq(&sem->wait_lock); + spin_lock_irqsave(&sem->wait_lock, flags); if (sem->activity == 0 && list_empty(&sem->wait_list)) { /* granted */ sem->activity = -1; - spin_unlock_irq(&sem->wait_lock); + spin_unlock_irqrestore(&sem->wait_lock, flags); goto out; } @@ -230,7 +232,7 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass) list_add_tail(&waiter.list, &sem->wait_list); /* we don't need to touch the semaphore struct anymore */ - spin_unlock_irq(&sem->wait_lock); + spin_unlock_irqrestore(&sem->wait_lock, flags); /* wait to be given the lock */ for (;;) { |