comedi: get rid of compat_alloc_user_space() mess in COMEDI_CMD{,TEST} compat

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index c40df64..dd14c29 100644 (file)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2931,155 +2931,106 @@ static int compat_rangeinfo(struct file *file, unsigned long arg)
 }
 
 /* Copy 32-bit cmd structure to native cmd structure. */
-static int get_compat_cmd(struct comedi_cmd __user *cmd,
+static int get_compat_cmd(struct comedi_cmd *cmd,
                          struct comedi32_cmd_struct __user *cmd32)
 {
-       int err;
-       union {
-               unsigned int uint;
-               compat_uptr_t uptr;
-       } temp;
-
-       /* Copy cmd structure. */
-       if (!access_ok(cmd32, sizeof(*cmd32)) ||
-           !access_ok(cmd, sizeof(*cmd)))
+       struct comedi32_cmd_struct v32;
+
+       if (copy_from_user(&v32, cmd32, sizeof(v32)))
                return -EFAULT;
 
-       err = 0;
-       err |= __get_user(temp.uint, &cmd32->subdev);
-       err |= __put_user(temp.uint, &cmd->subdev);
-       err |= __get_user(temp.uint, &cmd32->flags);
-       err |= __put_user(temp.uint, &cmd->flags);
-       err |= __get_user(temp.uint, &cmd32->start_src);
-       err |= __put_user(temp.uint, &cmd->start_src);
-       err |= __get_user(temp.uint, &cmd32->start_arg);
-       err |= __put_user(temp.uint, &cmd->start_arg);
-       err |= __get_user(temp.uint, &cmd32->scan_begin_src);
-       err |= __put_user(temp.uint, &cmd->scan_begin_src);
-       err |= __get_user(temp.uint, &cmd32->scan_begin_arg);
-       err |= __put_user(temp.uint, &cmd->scan_begin_arg);
-       err |= __get_user(temp.uint, &cmd32->convert_src);
-       err |= __put_user(temp.uint, &cmd->convert_src);
-       err |= __get_user(temp.uint, &cmd32->convert_arg);
-       err |= __put_user(temp.uint, &cmd->convert_arg);
-       err |= __get_user(temp.uint, &cmd32->scan_end_src);
-       err |= __put_user(temp.uint, &cmd->scan_end_src);
-       err |= __get_user(temp.uint, &cmd32->scan_end_arg);
-       err |= __put_user(temp.uint, &cmd->scan_end_arg);
-       err |= __get_user(temp.uint, &cmd32->stop_src);
-       err |= __put_user(temp.uint, &cmd->stop_src);
-       err |= __get_user(temp.uint, &cmd32->stop_arg);
-       err |= __put_user(temp.uint, &cmd->stop_arg);
-       err |= __get_user(temp.uptr, &cmd32->chanlist);
-       err |= __put_user((unsigned int __force *)compat_ptr(temp.uptr),
-                         &cmd->chanlist);
-       err |= __get_user(temp.uint, &cmd32->chanlist_len);
-       err |= __put_user(temp.uint, &cmd->chanlist_len);
-       err |= __get_user(temp.uptr, &cmd32->data);
-       err |= __put_user(compat_ptr(temp.uptr), &cmd->data);
-       err |= __get_user(temp.uint, &cmd32->data_len);
-       err |= __put_user(temp.uint, &cmd->data_len);
-       return err ? -EFAULT : 0;
+       cmd->subdev = v32.subdev;
+       cmd->flags = v32.flags;
+       cmd->start_src = v32.start_src;
+       cmd->start_arg = v32.start_arg;
+       cmd->scan_begin_src = v32.scan_begin_src;
+       cmd->scan_begin_arg = v32.scan_begin_arg;
+       cmd->convert_src = v32.convert_src;
+       cmd->convert_arg = v32.convert_arg;
+       cmd->scan_end_src = v32.scan_end_src;
+       cmd->scan_end_arg = v32.scan_end_arg;
+       cmd->stop_src = v32.stop_src;
+       cmd->stop_arg = v32.stop_arg;
+       cmd->chanlist = compat_ptr(v32.chanlist);
+       cmd->chanlist_len = v32.chanlist_len;
+       cmd->data = compat_ptr(v32.data);
+       cmd->data_len = v32.data_len;
+       return 0;
 }
 
 /* Copy native cmd structure to 32-bit cmd structure. */
 static int put_compat_cmd(struct comedi32_cmd_struct __user *cmd32,
-                         struct comedi_cmd __user *cmd)
-{
-       int err;
-       unsigned int temp;
-
-       /*
-        * Copy back most of cmd structure.
-        *
-        * Assume the pointer values are already valid.
-        * (Could use ptr_to_compat() to set them.)
-        */
-       if (!access_ok(cmd, sizeof(*cmd)) ||
-           !access_ok(cmd32, sizeof(*cmd32)))
-               return -EFAULT;
-
-       err = 0;
-       err |= __get_user(temp, &cmd->subdev);
-       err |= __put_user(temp, &cmd32->subdev);
-       err |= __get_user(temp, &cmd->flags);
-       err |= __put_user(temp, &cmd32->flags);
-       err |= __get_user(temp, &cmd->start_src);
-       err |= __put_user(temp, &cmd32->start_src);
-       err |= __get_user(temp, &cmd->start_arg);
-       err |= __put_user(temp, &cmd32->start_arg);
-       err |= __get_user(temp, &cmd->scan_begin_src);
-       err |= __put_user(temp, &cmd32->scan_begin_src);
-       err |= __get_user(temp, &cmd->scan_begin_arg);
-       err |= __put_user(temp, &cmd32->scan_begin_arg);
-       err |= __get_user(temp, &cmd->convert_src);
-       err |= __put_user(temp, &cmd32->convert_src);
-       err |= __get_user(temp, &cmd->convert_arg);
-       err |= __put_user(temp, &cmd32->convert_arg);
-       err |= __get_user(temp, &cmd->scan_end_src);
-       err |= __put_user(temp, &cmd32->scan_end_src);
-       err |= __get_user(temp, &cmd->scan_end_arg);
-       err |= __put_user(temp, &cmd32->scan_end_arg);
-       err |= __get_user(temp, &cmd->stop_src);
-       err |= __put_user(temp, &cmd32->stop_src);
-       err |= __get_user(temp, &cmd->stop_arg);
-       err |= __put_user(temp, &cmd32->stop_arg);
+                         struct comedi_cmd *cmd)
+{
+       struct comedi32_cmd_struct v32;
+
+       memset(&v32, 0, sizeof(v32));
+       v32.subdev = cmd->subdev;
+       v32.flags = cmd->flags;
+       v32.start_src = cmd->start_src;
+       v32.start_arg = cmd->start_arg;
+       v32.scan_begin_src = cmd->scan_begin_src;
+       v32.scan_begin_arg = cmd->scan_begin_arg;
+       v32.convert_src = cmd->convert_src;
+       v32.convert_arg = cmd->convert_arg;
+       v32.scan_end_src = cmd->scan_end_src;
+       v32.scan_end_arg = cmd->scan_end_arg;
+       v32.stop_src = cmd->stop_src;
+       v32.stop_arg = cmd->stop_arg;
        /* Assume chanlist pointer is unchanged. */
-       err |= __get_user(temp, &cmd->chanlist_len);
-       err |= __put_user(temp, &cmd32->chanlist_len);
-       /* Assume data pointer is unchanged. */
-       err |= __get_user(temp, &cmd->data_len);
-       err |= __put_user(temp, &cmd32->data_len);
-       return err ? -EFAULT : 0;
+       v32.chanlist = ptr_to_compat(cmd->chanlist);
+       v32.chanlist_len = cmd->chanlist_len;
+       v32.data = ptr_to_compat(cmd->data);
+       v32.data_len = cmd->data_len;
+       return copy_to_user(cmd32, &v32, sizeof(v32));
 }
 
 /* Handle 32-bit COMEDI_CMD ioctl. */
 static int compat_cmd(struct file *file, unsigned long arg)
 {
-       struct comedi_cmd __user *cmd;
-       struct comedi32_cmd_struct __user *cmd32;
+       struct comedi_file *cfp = file->private_data;
+       struct comedi_device *dev = cfp->dev;
+       struct comedi_cmd cmd;
+       bool copy = false;
        int rc, err;
 
-       cmd32 = compat_ptr(arg);
-       cmd = compat_alloc_user_space(sizeof(*cmd));
-
-       rc = get_compat_cmd(cmd, cmd32);
+       rc = get_compat_cmd(&cmd, compat_ptr(arg));
        if (rc)
                return rc;
 
-       rc = comedi_unlocked_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
-       if (rc == -EAGAIN) {
+       mutex_lock(&dev->mutex);
+       rc = do_cmd_ioctl(dev, &cmd, &copy, file);
+       mutex_unlock(&dev->mutex);
+       if (copy) {
                /* Special case: copy cmd back to user. */
-               err = put_compat_cmd(cmd32, cmd);
+               err = put_compat_cmd(compat_ptr(arg), &cmd);
                if (err)
                        rc = err;
        }
-
        return rc;
 }
 
 /* Handle 32-bit COMEDI_CMDTEST ioctl. */
 static int compat_cmdtest(struct file *file, unsigned long arg)
 {
-       struct comedi_cmd __user *cmd;
-       struct comedi32_cmd_struct __user *cmd32;
+       struct comedi_file *cfp = file->private_data;
+       struct comedi_device *dev = cfp->dev;
+       struct comedi_cmd cmd;
+       bool copy = false;
        int rc, err;
 
-       cmd32 = compat_ptr(arg);
-       cmd = compat_alloc_user_space(sizeof(*cmd));
-
-       rc = get_compat_cmd(cmd, cmd32);
+       rc = get_compat_cmd(&cmd, compat_ptr(arg));
        if (rc)
                return rc;
 
-       rc = comedi_unlocked_ioctl(file, COMEDI_CMDTEST, (unsigned long)cmd);
-       if (rc < 0)
-               return rc;
-
-       err = put_compat_cmd(cmd32, cmd);
-       if (err)
-               rc = err;
-
+       mutex_lock(&dev->mutex);
+       rc = do_cmdtest_ioctl(dev, &cmd, &copy, file);
+       mutex_unlock(&dev->mutex);
+       if (copy) {
+               err = put_compat_cmd(compat_ptr(arg), &cmd);
+               if (err)
+                       rc = err;
+       }
        return rc;
 }