diff options
| -rw-r--r-- | Documentation/userspace-api/ioctl/ioctl-number.rst | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 24c7f480e310..cbc65019879b 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -10,12 +10,14 @@ Michael Elizabeth Chastain If you are adding new ioctl's to the kernel, you should use the _IO macros defined in <linux/ioctl.h>: - ====== == ============================================ - _IO an ioctl with no parameters - _IOW an ioctl with write parameters (copy_from_user) - _IOR an ioctl with read parameters (copy_to_user) - _IOWR an ioctl with both write and read parameters. - ====== == ============================================ + ====== =========================== + macro parameters + ====== =========================== + _IO none + _IOW write (read from userspace) + _IOR read (write to userpace) + _IOWR write and read + ====== =========================== 'Write' and 'read' are from the user's point of view, just like the system calls 'write' and 'read'. For example, a SET_FOO ioctl would |