Mike Christie wrote: > James Bottomley wrote: >> On Mon, 2007-03-19 at 12:49 -0500, Mike Christie wrote: >>>> I can't even say if the tapes are written correctly as I can't read them >>>> (one does not reboot production machines back to 2.4.x just to try to >>>> read a backup tape - I don't have 2.6.x older than 2.6.20 on these >>>> machines). >>> Could you try this patch >>> http://marc.info/?l=linux-scsi&m=116464965414878&w=2 >>> I thought st was modified to not send offsets in the last elements but >>> it looks like it wasn't. >> Actually, there are two patches in the email referred to. If the >> analysis that we're passing NULL to mempool_free is correct, it should >> be the second one that fixes the problem (the one that checks >> bio->bi_io_vec before freeing it). Which would mean we have a >> nr_vecs==0 bio generated by the tar somehow. >> > > I think we might only need the first patch if the problem is similar to > what the lsi guys were seeing. I thought the problem is that we are not > estimating how large the transfer is correctly because we do not take > into account offsets at the end. This results in nr_vecs being zero when > it should be a valid value. I thought Kai's patch: > http://bugzilla.kernel.org/show_bug.cgi?id=7919 > http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=commitdiff;h=9abe16c670bd3d4ab5519257514f9f291383d104 > fixed the problem on st's side, but I guess not so you are probably right. > > Here is a patch that dumps the sgl we are getting from st so we can see > for sure what we are getting and can decide if we need the first patch, > second patch or both. > Here's the patch output: sg length 6 offset 0 sg length 12 offset 0 sg length 4096 offset 0 sg length 4096 offset 0 sg length 2048 offset 0 Please note (as replied in the other mail) that the bugzilla patch solves the problem. > > ------------------------------------------------------------------------ > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 5f95570..81005aa 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -306,6 +306,10 @@ static int scsi_req_map_sg(struct reques > struct bio *bio = NULL; > int i, err, nr_vecs = 0; > > + for (i = 0; i < nsegs; i++) > + printk(KERN_INFO "sg length %u offset %u\n", sgl[i].length, > + sgl[i].offset); > + > for (i = 0; i < nsegs; i++) { > page = sgl[i].page; > off = sgl[i].offset; -- Andreas Steinmetz SPAMmers use robotrap@xxxxxxxx - 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
