Re: [PATCH 1/4] nvdimm: Add wrapper for IOCTL pass thru.

[Jerry Hoemann]

On Tue, Nov 10, 2015 at 12:04:22PM -0700, Elliott, Robert (Persistent Memory) wrote:
> > -----Original Message-----
> > From: Linux-nvdimm [mailto:linux-nvdimm-bounces@xxxxxxxxxxxx] On Behalf Of
> > Hoemann, Jerry
> > Sent: Friday, November 6, 2015 4:27 PM
> > Subject: [PATCH 1/4] nvdimm: Add wrapper for IOCTL pass thru.
> ...
> > diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h
> ...
> > +struct ndn_pkg {
> > +	struct {
> > +		__u8	dsm_uuid[16];
> > +		__u32	dsm_in;			/* size of _DSM input    */
> > +		__u32	dsm_out;		/* size of user buffer   */
> > +		__u32	dsm_rev;		/* revision of dsm call  */
> > +		__u32	res[8];			/* reserved must be zero */
> > +		__u32	dsm_size;		/* size _DSM would write */
> > +	} h;
> > +	unsigned char buf[];
> > +} __packed;
> 
> Given that the _DSM arguments are defined as:
> * Arg0 UUID: Buffer of 16 bytes
> * Arg1 Revision ID: Integer (8 bytes)
> * Arg2 Function Index: Integer (8 bytes)
> * Arg3 Package: function-specific
> 
> 1. The __u32 for dsm_rev is not big enough to express all
> possible 8 byte Revision IDs.
> 
> 2. The unsigned int cmd (carried outside this structure)
> is not big enough on all platforms (e.g., 32-bit) to 
> express all possible Function Indexes.
> 
> 3. The Revision ID and Function Index values passed to 
> the _DSM are defined as little-endian.  Are they
> intended to use native endianness or be little-endian
> in this structure?
> 

  Thanks, Robert.  I will look at these for version 2.

  Jerry
-- 

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Jerry Hoemann            Software Engineer      Hewlett-Packard Enterprise

3404 E Harmony Rd. MS 36                        phone:  (970) 898-1022
Ft. Collins, CO 80528                           FAX:    (970) 898-0707
                                                email:  jerry.hoemann@xxxxxxx
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