Hi all,
I'd like to create some ioctl cmd's for the adapter driver that I am
writing. Looking at the code, it seems that the way to do this is to
just add an appropriate ioctl cmd to include/scsi/sg.h and the
scsi upper/mid layers will eventually call the adapter's ioctl() function
after not recognizing the particular ioctl cmd. (I'm using the ide-scsi
driver as a reference which is the only driver which uses the
SG_SET_TRANSFORM ioctl cmd according to sg.h).
So what's my problem? My problem is that I need to issue an ioctl() to
my adapter driver when there are no devices on the bus. Because there are
no devices on the bus, I can't open /dev/sg0 and therefore cannot issue an
ioctl.
I have thought of a few possible solutions, but wanted to see if someone
had a better idea:
1. Don't use ioctl() and just communicate over /proc
Yes this solution would work. However, it is my understanding that
writing to a /proc file is a linux specific semantic and may not be
available on other UNIX platforms. (I'd like to keep the code somewhat
portable). Can anyone comment on this?
2. Hack - have the adapter driver report a phony scsi device
Similar to what scsi_debug does I could create a bogus device and then
be able to do what i need by opening that device. I don't like this idea
much.
3. Personally ask Peter Anvin for my own /dev/myweirdhba entry.
This isn't the cleanest solution either.
The following idea I like best since its generic and could be used in the
future by other scsi adapters.
4. Have linux scsi developers agree on asking Peter Anvin for /dev/scsi0,
/dev/scsi1, /dev/scsi2, etc...
The idea here would be that /dev/scsi0 would be the first scsi adapter
on the machine, /dev/scsi1 would be the second, /dev/scsi2 would be the
third, etc. etc. Userspace programs would then be able to issue ioctl()'s
directly to any scsi adapter by first opening /dev/scsi0 etc.
What do people think?
-Michael F. Brown, UMass Lowell Computer Science
email: [EMAIL PROTECTED]
"I wonder if pawns just realize that they're just pawns
in someone's (chess) game." -L. Fitzgerald Sjoberg
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