This correspond to the NT syscall NtCreateEvent().
An NT event holds a single bit of state denoting whether it is signaled or unsignaled.
There are two types of events: manual-reset and automatic-reset. When an automatic-reset event is acquired via a wait function, its state is reset to unsignaled. Manual-reset events are not affected by wait functions.
Whether the event is manual-reset, and its initial state, are specified at creation time.
Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- drivers/misc/ntsync.c | 59 +++++++++++++++++++++++++++++++++++++ include/uapi/linux/ntsync.h | 6 ++++ 2 files changed, 65 insertions(+)
diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 03768ac25425..3e8827b6f480 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -26,6 +26,7 @@ enum ntsync_type { NTSYNC_TYPE_SEM, NTSYNC_TYPE_MUTEX, + NTSYNC_TYPE_EVENT, };
/* @@ -61,6 +62,10 @@ struct ntsync_obj { pid_t owner; bool ownerdead; } mutex; + struct { + bool manual; + bool signaled; + } event; } u;
/* @@ -233,6 +238,8 @@ static bool is_signaled(struct ntsync_obj *obj, __u32 owner) if (obj->u.mutex.owner && obj->u.mutex.owner != owner) return false; return obj->u.mutex.count < UINT_MAX; + case NTSYNC_TYPE_EVENT: + return obj->u.event.signaled; }
WARN(1, "bad object type %#x\n", obj->type); @@ -283,6 +290,10 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q, obj->u.mutex.count++; obj->u.mutex.owner = q->owner; break; + case NTSYNC_TYPE_EVENT: + if (!obj->u.event.manual) + obj->u.event.signaled = false; + break; } } wake_up_process(q->task); @@ -353,6 +364,28 @@ static void try_wake_any_mutex(struct ntsync_obj *mutex) } }
+static void try_wake_any_event(struct ntsync_obj *event) +{ + struct ntsync_q_entry *entry; + + ntsync_assert_held(event); + lockdep_assert(event->type == NTSYNC_TYPE_EVENT); + + list_for_each_entry(entry, &event->any_waiters, node) { + struct ntsync_q *q = entry->q; + int signaled = -1; + + if (!event->u.event.signaled) + break; + + if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) { + if (!event->u.event.manual) + event->u.event.signaled = false; + wake_up_process(q->task); + } + } +} + /* * Actually change the semaphore state, returning -EOVERFLOW if it is made * invalid. @@ -622,6 +655,27 @@ static int ntsync_create_mutex(struct ntsync_device *dev, void __user *argp) return fd; }
+static int ntsync_create_event(struct ntsync_device *dev, void __user *argp) +{ + struct ntsync_event_args args; + struct ntsync_obj *event; + int fd; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + + event = ntsync_alloc_obj(dev, NTSYNC_TYPE_EVENT); + if (!event) + return -ENOMEM; + event->u.event.manual = args.manual; + event->u.event.signaled = args.signaled; + fd = ntsync_obj_get_fd(event); + if (fd < 0) + kfree(event); + + return fd; +} + static struct ntsync_obj *get_obj(struct ntsync_device *dev, int fd) { struct file *file = fget(fd); @@ -752,6 +806,9 @@ static void try_wake_any_obj(struct ntsync_obj *obj) case NTSYNC_TYPE_MUTEX: try_wake_any_mutex(obj); break; + case NTSYNC_TYPE_EVENT: + try_wake_any_event(obj); + break; } }
@@ -941,6 +998,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd, void __user *argp = (void __user *)parm;
switch (cmd) { + case NTSYNC_IOC_CREATE_EVENT: + return ntsync_create_event(dev, argp); case NTSYNC_IOC_CREATE_MUTEX: return ntsync_create_mutex(dev, argp); case NTSYNC_IOC_CREATE_SEM: diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index 633958d90be3..e08aa02f4dcc 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -20,6 +20,11 @@ struct ntsync_mutex_args { __u32 count; };
+struct ntsync_event_args { + __u32 manual; + __u32 signaled; +}; + #define NTSYNC_WAIT_REALTIME 0x1
struct ntsync_wait_args { @@ -38,6 +43,7 @@ struct ntsync_wait_args { #define NTSYNC_IOC_WAIT_ANY _IOWR('N', 0x82, struct ntsync_wait_args) #define NTSYNC_IOC_WAIT_ALL _IOWR('N', 0x83, struct ntsync_wait_args) #define NTSYNC_IOC_CREATE_MUTEX _IOW ('N', 0x84, struct ntsync_mutex_args) +#define NTSYNC_IOC_CREATE_EVENT _IOW ('N', 0x87, struct ntsync_event_args)
#define NTSYNC_IOC_SEM_RELEASE _IOWR('N', 0x81, __u32) #define NTSYNC_IOC_MUTEX_UNLOCK _IOWR('N', 0x85, struct ntsync_mutex_args)