On Mon, 2008-12-01 at 17:52 -0800, Nicholas A. Bellinger wrote: > Greetings Tomo-san and Co, > > With the ongoing work in Linux/SCSI for v2.6.28 to map target mode > struct scatterlist memory directly down to struct scsi_cmnd without the > need for a intermediate struct bio as with the existing > scsi_execute_async(), I have started the porting process for the > Linux/SCSI subsystem plugin in generic target core v3.0 > (lio-core-2.6.git) on v2.6.28-rc6. > > So far, using struct request for ICF_SCSI_CONTROL_NONSG_IO_CDB is up > using blk_rq_map_kern(), as well as ICF_SCSI_NON_DATA_CDB ops using > struct request. In order to get the first READ_10s of type > ICF_SCSI_DATA_SG_IO_CDB to work, I had to add a temporary > EXPORT_SYMBOL_GPL() for drivers/scsi/scsi_lib.c:scsi_req_map_sg() in > lio-core-2.6.git for v2.6.28-rc6 in order to get TYPE_DISK up using an > software emulated MPT-Fusion HBA driver with struct request. I have > been looking at drivers/scsi/scsi_tgt_lib.c() (which currently uses > struct request), and I figure we need something similar for the generic > target infrastructure, although __scsi_get_command() and > __scsi_put_command() are currently used in that code. > > Below is what my patch looks like so far, I will probably just end up > commiting an temporary ifdef to keep scsi_execute_async() until the > proper pieces are in place and the other issues are resolved below. > >From there I will be able to drop in the proper upstream mapping bits > for struct scatterlist in > drivers/lio-core/target_core_pscsi.c:pscsi_map_task_SG() get rid of > scsi_req_map_sg() usage all together. > > So far during my initial testing, I am running into a two different > exceptions. One NULL pointer deference OOPS after half dozen Open/iSCSI > login/logouts in block/elevator.c:elv_dequeue_request(). Here is the > trace from SCSI softirq context: > > http://linux-iscsi.org/builds/user/nab/2.6.28-rc6-oops-0.png > http://linux-iscsi.org/builds/user/nab/2.6.28-rc6-oops-1.png > > The other one is a BUG_ON in blk/blk-timeout.c:177 in blk_add_timeout() > that happens after a few hundred MB of READ_10 traffic, which also > appears to pass through elv_dequeue_request() at some point: > > http://linux-iscsi.org/builds/user/nab/2.6.28-rc6-oops-2.png > http://linux-iscsi.org/builds/user/nab/2.6.28-rc6-oops-4.png > Ok, I just saw this patch: [PATCH 2.6.28-rc6] block: internal dequeue shouldn't start timer at http://lkml.org/lkml/2008/11/27/394. It sounds very similar and I will try it out and see if it resolves the issues above. Thanks, --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
