Increase spl_kmem_alloc_warn limit

[mirror_zfs.git] / module / spl / spl-rwlock.c

diff --git a/module/spl/spl-rwlock.c b/module/spl/spl-rwlock.c
index c0f974f1bf2a266d7ceaffb6385dcef090a992ad..77f46f2d6fdf5119132424fe396de23378d4e644 100644 (file)
--- a/module/spl/spl-rwlock.c
+++ b/module/spl/spl-rwlock.c
@@ -6,7 +6,7 @@
  *  UCRL-CODE-235197
  *
  *  This file is part of the SPL, Solaris Porting Layer.
- *  For details, see <http://github.com/behlendorf/spl/>.
+ *  For details, see <http://zfsonlinux.org/>.
  *
  *  The SPL is free software; you can redistribute it and/or modify it
  *  under the terms of the GNU General Public License as published by the
@@ -32,65 +32,55 @@
 
 #define DEBUG_SUBSYSTEM S_RWLOCK
 
-#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
-
-/*
- * From lib/rwsem-spinlock.c but modified such that the caller is
- * responsible for acquiring and dropping the sem->wait_lock.
- */
-struct rwsem_waiter {
-        struct list_head list;
-        struct task_struct *task;
-        unsigned int flags;
-#define RWSEM_WAITING_FOR_READ  0x00000001
-#define RWSEM_WAITING_FOR_WRITE 0x00000002
-};
-
-/* wake a single writer */
-static struct rw_semaphore *
-__rwsem_wake_one_writer_locked(struct rw_semaphore *sem)
+#if defined(CONFIG_RWSEM_GENERIC_SPINLOCK)
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
 {
-        struct rwsem_waiter *waiter;
-        struct task_struct *tsk;
-
-        sem->activity = -1;
-
-        waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-        list_del(&waiter->list);
-
-        tsk = waiter->task;
-        smp_mb();
-        waiter->task = NULL;
-        wake_up_process(tsk);
-        put_task_struct(tsk);
-        return sem;
+       int ret = 0;
+       unsigned long flags;
+       spl_rwsem_lock_irqsave(&rwsem->wait_lock, flags);
+       if (RWSEM_COUNT(rwsem) == SPL_RWSEM_SINGLE_READER_VALUE &&
+           list_empty(&rwsem->wait_list)) {
+               ret = 1;
+               RWSEM_COUNT(rwsem) = SPL_RWSEM_SINGLE_WRITER_VALUE;
+       }
+       spl_rwsem_unlock_irqrestore(&rwsem->wait_lock, flags);
+       return (ret);
 }
-
-/* release a read lock on the semaphore */
-void
-__up_read_locked(struct rw_semaphore *sem)
+#elif defined(HAVE_RWSEM_ATOMIC_LONG_COUNT)
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
 {
-        if (--sem->activity == 0 && !list_empty(&sem->wait_list))
-                (void)__rwsem_wake_one_writer_locked(sem);
+       long val;
+       val = atomic_long_cmpxchg(&rwsem->count, SPL_RWSEM_SINGLE_READER_VALUE,
+           SPL_RWSEM_SINGLE_WRITER_VALUE);
+       return (val == SPL_RWSEM_SINGLE_READER_VALUE);
 }
-EXPORT_SYMBOL(__up_read_locked);
-
-/* trylock for writing -- returns 1 if successful, 0 if contention */
-int
-__down_write_trylock_locked(struct rw_semaphore *sem)
+#else
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
 {
-        int ret = 0;
-
-        if (sem->activity == 0 && list_empty(&sem->wait_list)) {
-                sem->activity = -1;
-                ret = 1;
-        }
-
-        return ret;
+       typeof (rwsem->count) val;
+       val = cmpxchg(&rwsem->count, SPL_RWSEM_SINGLE_READER_VALUE,
+           SPL_RWSEM_SINGLE_WRITER_VALUE);
+       return (val == SPL_RWSEM_SINGLE_READER_VALUE);
 }
-EXPORT_SYMBOL(__down_write_trylock_locked);
+#endif
 
+int
+rwsem_tryupgrade(struct rw_semaphore *rwsem)
+{
+       if (__rwsem_tryupgrade(rwsem)) {
+               rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+               rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+               rwsem->owner = current;
 #endif
+               return (1);
+       }
+       return (0);
+}
+EXPORT_SYMBOL(rwsem_tryupgrade);
 
 int spl_rw_init(void) { return 0; }
 void spl_rw_fini(void) { }