From 049500715e7aed436c3dfac7071d7f17c18b463b Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Thu, 3 Oct 2019 13:02:19 -0600 Subject: docs: Move the user-space ioctl() docs to userspace-api This is strictly user-space material at this point, so put it with the other user-space API documentation. Signed-off-by: Jonathan Corbet --- Documentation/ioctl/ioctl-decoding.rst | 31 ------------------------------- 1 file changed, 31 deletions(-) delete mode 100644 Documentation/ioctl/ioctl-decoding.rst (limited to 'Documentation/ioctl/ioctl-decoding.rst') diff --git a/Documentation/ioctl/ioctl-decoding.rst b/Documentation/ioctl/ioctl-decoding.rst deleted file mode 100644 index 380d6bb3e3ea..000000000000 --- a/Documentation/ioctl/ioctl-decoding.rst +++ /dev/null @@ -1,31 +0,0 @@ -============================== -Decoding an IOCTL Magic Number -============================== - -To decode a hex IOCTL code: - -Most architectures use this generic format, but check -include/ARCH/ioctl.h for specifics, e.g. powerpc -uses 3 bits to encode read/write and 13 bits for size. - - ====== ================================== - bits meaning - ====== ================================== - 31-30 00 - no parameters: uses _IO macro - 10 - read: _IOR - 01 - write: _IOW - 11 - read/write: _IOWR - - 29-16 size of arguments - - 15-8 ascii character supposedly - unique to each driver - - 7-0 function # - ====== ================================== - - -So for example 0x82187201 is a read with arg length of 0x218, -character 'r' function 1. Grepping the source reveals this is:: - - #define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct dirent [2]) -- cgit v1.2.3