On Sun, 2009-04-19 at 13:56 +0300, Boaz Harrosh wrote: > On 04/17/2009 04:09 AM, Nicholas A. Bellinger wrote: > > Greetings all, > > > > This patch modifies the Target_Core_Mod/ConfigFS v3.0 PSCSI subsystem plugin for target_core_mod v3.0 to add > > a configurable method of choosing legacy scsi_execute_async() usage for underlying SCSI HTCL struct scsi_device. > > This method is still the only method of issuing I/O to the Linux SCSI subsystem is used for non TYPE_DISK hardware > > SCSI and SATA devices that appear under Linux-SCSI, but have not yet been updated to accept raw struct request > > operations directly. Some of these include TYPE_ROM, TYPE_TYPE and TYPE_MEDIUM_CHANGER hardware. > > > > This method can be used be used via ConfigFS as follows: > > > > export TARGET=/sys/kernel/config/target/core/ > > # load target_core_mod > > modprobe target_core_mod > > # The Linux/SCSI scsi host id is part of pscsi_$HOST_ID HBA name.. > > mkdir -p $TARGET/pscsi_0/sr0 > > # echo CTL to the control configfs attribute > > echo scsi_channel_id=0,scsi_target_id=0,scsi_lun_id=0 > $TARGET/pscsi_0/sr0/control > > # Activate the target_core_mod/ConfigFS PSCSI storage object > > echo 1 > $TARGET/pscsi_0/sr0/enable > > > > At this point, creating symlinks for SCSI target ports to configfs enabled fabric modules > > against PSCSI hardware passthrough using te HCTL reference will work. > > > > This patch are made against lio-core-2.6.git/master and tested on > > v2.6.29 x86 32-bit HVM with TYPE_DISK and v2.6.29 ppc64 with TYPE_ROM. > > The lio-core-2.6.git tree can be found at: > > > > http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=summary > > > > :-) > > > > Are you aware that scsi_execute_async() has gone in 2.6.30-rc1? > > I'm not sure what would be the best alternative for you. I would say > a bio, but it is still being debated. Your current options are: > > 1. bio_alloc then loop () bio_add_pc_page, and finally blk_rq_append_bio > (Which block people don't like) > 2. sglist => page-pointers-array translation and blk_rq_map_user with > struct rq_map_data mode. (not possible with all kind of sglists) > 2. sglist => iovec translation and blk_rq_map_user_iov() > (Very very ugly mapping of pages to virtual pointers) > > I have a similar situation with my OSD code. > Hey, Thanks for the pointers on this.. Yeah, I knew it was going away soon, but needed it for some legacy drivers..:-) Anyways, I will drop this patch for scsi_execute_async() when I branch for v2.6.30-rcX and look and updating target_core_mod/pSCSI to one of the listed methods to get up and running. From the looks of it however we might want something slightly better than blk_rq_map_user() for the kernel space pages attached to struct scatterlist and page_links.. Just FYI, the target_core_mod struct scatterlist memory will be in struct list_head with struct page for allocated se_cmd_t (received CDB), so it will be pretty easy from the target_core_mod+subsystem plugin side side to put something that along the lines of list => page-pointers-array translation and blk_rq_map_user() into a new function.. lio-core-2.6.git/drivers/target/target_core_transport.c is using include/linux/scatterlist.h macros when interacting with struct scatterlist allocated for each subsystem plugin (from the linked list struct page memory) I will have a look and see what would need to be down to allow all kinds of sglists with something new.. Thanks for your comments! --nab -- 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
