[dm-devel] [RFC] DM_TARGET_CTL: ioctl interface

[Mike Christie]

Alasdair G Kergon wrote:
> On Tue, May 25, 2004 at 01:55:23PM +0100, Alasdair G Kergon wrote:
> 
>>On Mon, May 24, 2004 at 06:00:19PM -0700, Mike Christie wrote:
>>
>>>Is there any way
>>>I could pass in such a thing when my target is created, so that way dm 
>>>multipath
>>>would not have any type of command format functions/modules or definitions
>>>(it could just be passed in and built like the sg io code).
>>
>>We've been talking about a new dm ioctl for passing arbitrary commands 
>>to a target, which I think would cover this.  
> 
> 
> dm-ioctl.h:
>   #define DM_TARGET_CTL	 _IOWR(DM_IOCTL, DM_TARGET_CTL_CMD, struct dm_ioctl)
> 
>   struct dm_target_ctl {
> 	uint64_t sector;	/* Device sector */
> 	/* Might add size of command string if it simplifies processing */
> 
> 	char command[0];
>   };
> 
> Is there any legitimate need to supply a list of dm_target_ctl structs
> instead of just one-at-once?

I do not have one.

> Is there any need to allow a string of data to be returned in addition
> to the error code?  [i.e. Are status/table commands sufficient? ]

I also do not have one....

But Christophe V. really does all the userspace stuff, so he would know best.

> Alasdair


-- 
Mike Christie
mikenc at us.ibm.com