On Thu, 2010-08-19 at 23:03 +0900, FUJITA Tomonori wrote: > On Wed, 18 Aug 2010 18:01:37 -0700 > "Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx> wrote: > > > BSG exposes more raw functionality (but certaily not all) of the modern > > Linux Block layer code. This includes the ability to do BIDI commands > > and support for legacy SG_IO ioctls in block/bsg.c:bsg_ioctl(). > > > > Note that not all of the the structure members in struct sg_io_v4 can > > safely be used with current mainline code. For example, having a 32-bit > > userspace passing up 32-bit pointers currently need a patch to require > > proper conversion to 64-bit struct scatterlist memory. The first half > > of this patch is here: > > > > http://groups.google.com/group/linux-iscsi-target-dev/browse_thread/thread/6b9f8a08f78067dc/6330a5897203854a?lnk=gst&q=BSG#6330a5897203854a > > > > This issue came up again between Tomo-san and myself last week, and we > > agreed that the patch to make 32-bit user + 64-bit kernel work with BSG > > scatterlists would not be pretty, > > Sorry, we agreed about it? I'm not sure about. I really want to avoid > the compat code for bsg read/write interface. > > I just want to say, bsg doesn't support such configuration and use > 64-bit user space. > > Hmmm, then it must have been Dr. Hannes.. ;) The bigger issue for BSG is wrt to QEMUSGList when we are forced to use non-contigious physical memory, instead of the (always?) contigious memory that STGT is assigning to struct sg_io_v4->d[out,in]_xferp, and in usr/bs_sg.c:bs_bsg_cmd_submit(). Since 64-bit kernel / 32-bit userspace for QEMU-KVM BSG is still broken with the above patch to block/bsg.c that allows QEMU-KVM BSG to function on 64-bit kernel / userspace. I think this particular issue does need to be addressed for those users, even if it is just a temporary measure that we removed at some point in the future. Best, --nab -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
