cvs commit: src/sys/cam/scsi scsi_sg.c scsi_sg.h src/sys/modules/cam Makefile src/sys/conf NOTES files src/sys/compat/linux linux_ioctl.c linux_ioctl.h

mjacob at mjacob at
Sun Apr 8 01:01:21 UTC 2007

Oh, agreed that it's unpleasant. Better than Solaris tho.

By doing this you may have made FreeBSD a viable choice with respect to 
storagse. There are a lot of management tools for linux storage that use 
the sg interfaces. Bravo.

> To tell you the truth, the SG device has one of the worst programming 
> interfaces that I've ever seen.  Even the various official docs on it
> complain about how bad it is.  I've written apps for CAM, including a
> swiss-army-knife java-based management app, and CAM is vastly superior.
> I tried porting the app to linux and gave up due to how limited and
> unpleasant it was.  From the kernel side, it's even scarier.
> But beyond that, the work I committed here was about opening up FreeBSD
> to more storage management opportunities.  So I'm happy with whatever
> anyone wants to do with it that furthers that goal.  I'd like to see
> the native interface be used as a bridge to help introduce programmers
> to FreeBSD and CAM; if the sg3_utils package is a step in that
> direction or if it provides tools that camcontrol doesn't, then go for
> it.
> Scott
> mjacob at wrote:
>> Cool- does this mean we should commit sg3_utils to ports then?
>> On Sat, 7 Apr 2007, Scott Long wrote:
>>> scottl      2007-04-07 19:40:58 UTC
>>>  FreeBSD src repository
>>>  Modified files:
>>>    sys/modules/cam      Makefile
>>>    sys/conf             files NOTES
>>>    sys/compat/linux     linux_ioctl.c linux_ioctl.h
>>>  Added files:
>>>    sys/cam/scsi         scsi_sg.c scsi_sg.h
>>>  Log:
>>>  Add the CAM 'SG' peripheral device.  This device implements a subset of 
>>> the
>>>  Linux SCSI SG passthrough device API.  The intention is to allow for both
>>>  running of Linux apps that want to talk to /dev/sg* nodes, and to 
>>> facilitate
>>>  porting of apps from Linux to FreeBSD.  As such, both native and 
>>> linuxolator
>>>  entry points and definitions are provided.
>>>  Caveats:
>>>   - This does not support the procfs and sysfs nodes that the Linux SG
>>>     driver provides.  Some Linux apps may rely on these for operation,
>>>     others may only use them for informational purposes.
>>>   - More ioctls need to be implemented.
>>>   - Linux uses a naming scheme of "sg[a-z]" for devices, while FreeBSD 
>>> uses a
>>>     scheme of "sg[0-9]".  Devfs aliasis (symlinks) are automatically 
>>> created
>>>     to link the two together.  However, tools like camcontrol only see the
>>>     native names.
>>>   - Some operations were originally designed to return byte counts or 
>>> other
>>>     data directly as the syscall return value.  The linuxolator doesn't 
>>> appear
>>>     to support this well, so this driver just punts for these cases.
>>>  Now that the driver is in place, others are welcome to add missing
>>>  functionality.  Thanks to Roman Divacky for pushing this work along.
>>>  Revision  Changes    Path
>>>  1.1       +987 -0    src/sys/cam/scsi/scsi_sg.c (new)
>>>  1.1       +139 -0    src/sys/cam/scsi/scsi_sg.h (new)
>>>  1.138     +27 -0     src/sys/compat/linux/linux_ioctl.c
>>>  1.25      +34 -0     src/sys/compat/linux/linux_ioctl.h
>>>  1.1419    +5 -0      src/sys/conf/NOTES
>>>  1.1191    +1 -0      src/sys/conf/files
>>>  1.15      +1 -0      src/sys/modules/cam/Makefile

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