148 lines
3.8 KiB
Diff
148 lines
3.8 KiB
Diff
This corresponds to the NT syscall NtReleaseSemaphore().
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Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
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---
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drivers/misc/ntsync.c | 76 +++++++++++++++++++++++++++++++++++++
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include/uapi/linux/ntsync.h | 2 +
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2 files changed, 78 insertions(+)
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diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
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index 3287b94be351..d1c91c2a4f1a 100644
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--- a/drivers/misc/ntsync.c
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+++ b/drivers/misc/ntsync.c
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@@ -21,9 +21,11 @@ enum ntsync_type {
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struct ntsync_obj {
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struct rcu_head rhead;
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struct kref refcount;
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+ spinlock_t lock;
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enum ntsync_type type;
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+ /* The following fields are protected by the object lock. */
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union {
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struct {
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__u32 count;
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@@ -36,6 +38,19 @@ struct ntsync_device {
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struct xarray objects;
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};
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+static struct ntsync_obj *get_obj(struct ntsync_device *dev, __u32 id)
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+{
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+ struct ntsync_obj *obj;
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+
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+ rcu_read_lock();
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+ obj = xa_load(&dev->objects, id);
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+ if (obj && !kref_get_unless_zero(&obj->refcount))
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+ obj = NULL;
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+ rcu_read_unlock();
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+
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+ return obj;
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+}
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+
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static void destroy_obj(struct kref *ref)
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{
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struct ntsync_obj *obj = container_of(ref, struct ntsync_obj, refcount);
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@@ -48,6 +63,18 @@ static void put_obj(struct ntsync_obj *obj)
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kref_put(&obj->refcount, destroy_obj);
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}
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+static struct ntsync_obj *get_obj_typed(struct ntsync_device *dev, __u32 id,
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+ enum ntsync_type type)
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+{
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+ struct ntsync_obj *obj = get_obj(dev, id);
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+
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+ if (obj && obj->type != type) {
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+ put_obj(obj);
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+ return NULL;
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+ }
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+ return obj;
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+}
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+
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static int ntsync_char_open(struct inode *inode, struct file *file)
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{
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struct ntsync_device *dev;
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@@ -81,6 +108,7 @@ static int ntsync_char_release(struct inode *inode, struct file *file)
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static void init_obj(struct ntsync_obj *obj)
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{
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kref_init(&obj->refcount);
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+ spin_lock_init(&obj->lock);
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}
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static int ntsync_create_sem(struct ntsync_device *dev, void __user *argp)
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@@ -131,6 +159,52 @@ static int ntsync_delete(struct ntsync_device *dev, void __user *argp)
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return 0;
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}
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+/*
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+ * Actually change the semaphore state, returning -EOVERFLOW if it is made
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+ * invalid.
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+ */
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+static int put_sem_state(struct ntsync_obj *sem, __u32 count)
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+{
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+ lockdep_assert_held(&sem->lock);
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+
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+ if (sem->u.sem.count + count < sem->u.sem.count ||
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+ sem->u.sem.count + count > sem->u.sem.max)
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+ return -EOVERFLOW;
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+
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+ sem->u.sem.count += count;
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+ return 0;
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+}
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+
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+static int ntsync_put_sem(struct ntsync_device *dev, void __user *argp)
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+{
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+ struct ntsync_sem_args __user *user_args = argp;
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+ struct ntsync_sem_args args;
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+ struct ntsync_obj *sem;
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+ __u32 prev_count;
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+ int ret;
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+
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+ if (copy_from_user(&args, argp, sizeof(args)))
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+ return -EFAULT;
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+
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+ sem = get_obj_typed(dev, args.sem, NTSYNC_TYPE_SEM);
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+ if (!sem)
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+ return -EINVAL;
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+
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+ spin_lock(&sem->lock);
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+
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+ prev_count = sem->u.sem.count;
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+ ret = put_sem_state(sem, args.count);
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+
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+ spin_unlock(&sem->lock);
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+
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+ put_obj(sem);
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+
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+ if (!ret && put_user(prev_count, &user_args->count))
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+ ret = -EFAULT;
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+
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+ return ret;
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+}
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+
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static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
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unsigned long parm)
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{
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@@ -142,6 +216,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
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return ntsync_create_sem(dev, argp);
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case NTSYNC_IOC_DELETE:
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return ntsync_delete(dev, argp);
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+ case NTSYNC_IOC_PUT_SEM:
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+ return ntsync_put_sem(dev, argp);
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default:
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return -ENOIOCTLCMD;
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}
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diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
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index d97afc138dcc..8c610d65f8ef 100644
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--- a/include/uapi/linux/ntsync.h
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+++ b/include/uapi/linux/ntsync.h
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@@ -21,5 +21,7 @@ struct ntsync_sem_args {
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#define NTSYNC_IOC_CREATE_SEM _IOWR(NTSYNC_IOC_BASE, 0, \
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struct ntsync_sem_args)
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#define NTSYNC_IOC_DELETE _IOW (NTSYNC_IOC_BASE, 1, __u32)
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+#define NTSYNC_IOC_PUT_SEM _IOWR(NTSYNC_IOC_BASE, 2, \
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+ struct ntsync_sem_args)
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#endif
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--
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2.43.0
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