strace ioctls use only 16 bit?

Michael Holzheu HOLZHEU at
Wed Mar 10 05:25:05 UTC 2004

Hi all,

I have a simple question.

In ioctl_lookup() we only use the lower 16 bits of the ioctl number:

#ifdef LINUX
        ioent.code &= (_IOC_NRMASK<<_IOC_NRSHIFT) |

For our dasd driver we have e.g. the following ioctls:

BIODASDFMT          : 0x40104401

At the moment straces reports BIODASDENABLE, if a BIODASDFMT ioctl() is

Why do we not look at the complete ioctl code?
Maybe the reuse of ioctls is a bug in our dasd driver.



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