96 lines
2.6 KiB
Diff
96 lines
2.6 KiB
Diff
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From cc9ade623cd90cd002fb86f3aa249af2e6e4019e Mon Sep 17 00:00:00 2001
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From: Elizabeth Figura <zfigura@codeweavers.com>
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Date: Sun, 19 May 2024 15:24:30 -0500
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Subject: ntsync: Introduce NTSYNC_IOC_MUTEX_UNLOCK.
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This corresponds to the NT syscall NtReleaseMutant().
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This syscall decrements the mutex's recursion count by one, and returns the
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previous value. If the mutex is not owned by the current task, the function
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instead fails and returns -EPERM.
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Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
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---
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drivers/misc/ntsync.c | 53 +++++++++++++++++++++++++++++++++++++
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include/uapi/linux/ntsync.h | 1 +
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2 files changed, 54 insertions(+)
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--- a/drivers/misc/ntsync.c
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+++ b/drivers/misc/ntsync.c
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@@ -396,6 +396,57 @@ static int ntsync_sem_post(struct ntsync
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return ret;
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}
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+/*
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+ * Actually change the mutex state, returning -EPERM if not the owner.
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+ */
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+static int unlock_mutex_state(struct ntsync_obj *mutex,
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+ const struct ntsync_mutex_args *args)
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+{
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+ ntsync_assert_held(mutex);
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+
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+ if (mutex->u.mutex.owner != args->owner)
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+ return -EPERM;
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+
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+ if (!--mutex->u.mutex.count)
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+ mutex->u.mutex.owner = 0;
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+ return 0;
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+}
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+
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+static int ntsync_mutex_unlock(struct ntsync_obj *mutex, void __user *argp)
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+{
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+ struct ntsync_mutex_args __user *user_args = argp;
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+ struct ntsync_device *dev = mutex->dev;
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+ struct ntsync_mutex_args args;
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+ __u32 prev_count;
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+ bool all;
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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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+ if (!args.owner)
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+ return -EINVAL;
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+
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+ if (mutex->type != NTSYNC_TYPE_MUTEX)
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+ return -EINVAL;
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+
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+ all = ntsync_lock_obj(dev, mutex);
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+
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+ prev_count = mutex->u.mutex.count;
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+ ret = unlock_mutex_state(mutex, &args);
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+ if (!ret) {
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+ if (all)
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+ try_wake_all_obj(dev, mutex);
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+ try_wake_any_mutex(mutex);
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+ }
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+
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+ ntsync_unlock_obj(dev, mutex, all);
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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 int ntsync_obj_release(struct inode *inode, struct file *file)
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{
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struct ntsync_obj *obj = file->private_data;
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@@ -415,6 +466,8 @@ static long ntsync_obj_ioctl(struct file
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switch (cmd) {
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case NTSYNC_IOC_SEM_POST:
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return ntsync_sem_post(obj, argp);
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+ case NTSYNC_IOC_MUTEX_UNLOCK:
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+ return ntsync_mutex_unlock(obj, argp);
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default:
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return -ENOIOCTLCMD;
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}
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--- a/include/uapi/linux/ntsync.h
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+++ b/include/uapi/linux/ntsync.h
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@@ -42,5 +42,6 @@ struct ntsync_wait_args {
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#define NTSYNC_IOC_CREATE_MUTEX _IOWR('N', 0x84, struct ntsync_sem_args)
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#define NTSYNC_IOC_SEM_POST _IOWR('N', 0x81, __u32)
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+#define NTSYNC_IOC_MUTEX_UNLOCK _IOWR('N', 0x85, struct ntsync_mutex_args)
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#endif
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