On Fri, 2008-10-17 at 12:48 -0700, Joel Becker wrote: > On Fri, Oct 17, 2008 at 01:22:18AM -0700, Nicholas A. Bellinger wrote: > > On Fri, 2008-10-17 at 00:44 -0700, Greg KH wrote: > > > What is the problem you are attempting to solve here? > > > > > > > So, the generic target_core_mod engine that lives > > under /sys/kernel/config/target/core needs a method to locate struct > > block_device and struct scsi_device for access via bio_submit() and > > scsi_execute_() respectively. > > > > Originally, target_core_mod used key echoed through configfs attributes > > like so: > > > > export TARGET=/sys/kernel/config/target/core/ > > > > # Create $STORAGE_OBJECT of type Linux/BLOCK in generic target_core_mod > > mkdir -p $TARGET/iblock_0/lvm_test0 > > # OLD METHOD to reference struct block_device > > echo iblock_major=254,iblock_minor=2 > $TARGET/iblock_0/lvm_test0/control > > echo 1 > $TARGET/iblock_0/lvm_test0/enable > > # NEW METHOD using sysfs ->configfs symlinks to reference struct block_device > > ln -s /sys/block/dm-2 $TARGET/iblock_0/lvm_test0/dm-2 > > Pass an open file descriptor. In bash(1): > > exec 3<>/dev/dm-7 > echo 3 >$TARGET/iblock_0/lvm_test0/control # I'd call it 'fd' > > In kernel, in the ->store() function of 'control': > > p = (char *)page; > fd = simple_strtol(p, &p, 0); > filp = fget(fd); > inode = igrab(filp->f_mapping->host); > dev = I_BDEV(filp->f_mapping->host); > blkdev_get(dev, FMODE_WRITE | FMODE_READ, 0); > > Error handling is left up to you (validate the strtol, fd range, ISBLK, > etc). This assumes you want the struct block_device and want to pin it > in memory. I assume you do. > <nod> Sounds good.. I will go about converting the target_core_mod subsystem plugins to use this method.. Thanks Joel! --nab > Joel > -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
