Douglas Gilbert wrote:
Mike Christie wrote:
The attach patch converts scsi_debug to use the virtual scsi bus.
It was built against scsi-rc-fixes-2.6.
The interface has changed a little. Here is an
example of adding and removing a single host:
cd /sys/bus/scsi_host/drivers/scsi_debug
[EMAIL PROTECTED] scsi_debug]# ls
add_host dev_size_mb every_nth module num_parts opts scsi_level
delay dsense max_luns num_hosts num_tgts ptype
[EMAIL PROTECTED] scsi_debug]# echo 1 > add_host
[EMAIL PROTECTED] scsi_debug]# ls
add_host dev_size_mb every_nth module num_parts opts scsi_level
delay dsense max_luns num_hosts num_tgts ptype virt_host4
[EMAIL PROTECTED] scsi_debug]# cd virt_host4/
[EMAIL PROTECTED] virt_host4]# ls
detach_state driver host4 power remove_host
[EMAIL PROTECTED] virt_host4]# echo 1 > remove_host
Mike,
I have noticed a few differences in the scsi_debug
driver with this patch applied.
Firstly, when loaded the scsi_debug driver has no hosts
and thus no devices. Previously it defaulted to 1 host,
1 target and 1 lun (hence 1 device). Now a user needs
to do something like:
$ modprobe scsi_debug
$ cd /sys/bus/scsi_host/drivers/scsi_debug
$ echo 42 > add_host
This is just a result of me trying to emulate
normal HW drivers. For example I did not see
any that would add the bus's device (the device
equivalent to a pci_dev for example), so this
is why I was always just doing the additions
from userspace.
I can break out part of scsi_host_driver_add_host
and export it so LLDs can call it and
add hosts from the kernel for scsi_debug.
The next issue is the number passed to "add_host".
It doesn't matter, one host is added. When add_host
belonged to scsi_debug the number and sign of the
value sent to add_host was significant (and a negative
number tried to remove that number of hosts).
Perhaps we could get that capability back by making
"num_hosts" writeable.
I can easily add both behaviors back to the "add_host"
attr.
Otherwise it looks good and fixes the "pseudo" bus
problem which prevented two or more drivers using
the "pseudo" bus at the same time.
Doug Gilbert
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