After turning on DEBUG_SG I hit a fail:
kernel BUG at include/linux/scatterlist.h:50!
ata_qc_issue
ata_scsi_translate
ipr_queuecommand
scsi_dispatch_cmd
scsi_request_fn
elv_insert
blk_execute_rq_nowait
blk_execute_rq
sg_io
scsi_cmd_ioctl
cdrom_ioctl
sr_block_ioctl
blkdev_driver_ioctl
blkdev_ioctl
block_ioctl
do_ioctl
vfs_ioctl
sys_ioctl
sg_ioctl_trans
It looks like ata_sg_setup is working on an uninitialised sg table. Call
sg_init_table to initialise it before use.
Signed-off-by: Anton Blanchard <anton@samba.org>
Note: this patch will fix it, but you could also get away with just
doing the sg_init_table() once at qc creation time.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
acd054a5ef