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author | Jonathan Corbet <corbet@lwn.net> | 2019-10-03 13:02:19 -0600 |
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committer | Jonathan Corbet <corbet@lwn.net> | 2019-10-10 11:21:54 -0600 |
commit | 049500715e7aed436c3dfac7071d7f17c18b463b (patch) | |
tree | 78677fa3c6df0b417fc35623cda950fc3d608adc /Documentation/ioctl/ioctl-decoding.rst | |
parent | 5ecd0a06e6bb992c903f5d8a588b78852b9e80a5 (diff) |
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 <corbet@lwn.net>
Diffstat (limited to 'Documentation/ioctl/ioctl-decoding.rst')
-rw-r--r-- | Documentation/ioctl/ioctl-decoding.rst | 31 |
1 files changed, 0 insertions, 31 deletions
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]) |