Revision a45dc2d2b8d1afa57c91dcfac224e50ffcd3f805 authored by Benny Halevy on 13 September 2010, 19:32:19 UTC, committed by Jens Axboe on 21 September 2010, 09:49:17 UTC
This bug was introduced in 7b6d91daee5cac6402186ff224c3af39d79f4a0e
"block: unify flags for struct bio and struct request"

Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
1 parent b0722cb
Raw File
ioctl-decoding.txt
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])
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