On Sun, Jul 29, 2012 at 8:33 PM, Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote: > n Wed, 2012-07-18 at 18:49 +0200, olaf@xxxxxxxxx wrote: >> From: Linda Xie <lxiep@xxxxxxxxxx> >> >> Expected result: >> It should show something like this: >> x1521p4:~ # cat /sys/class/scsi_host/host1/config >> PARTITIONNAME='x1521p4' >> NWSDNAME='X1521P4' >> HOSTNAME='X1521P4' >> DOMAINNAME='RCHLAND.IBM.COM' >> NAMESERVERS='9.10.244.100 9.10.244.200' >> >> Actual result: >> x1521p4:~ # cat /sys/class/scsi_host/host0/config >> x1521p4:~ # >> >> This patch changes the size of the buffer used for transfering config >> data to 4K. It was tested against 2.6.19-rc2 tree. >> >> Reported by IBM during SLES11 beta testing: > > So this patch just seems to blindly replace all occurrences of PAGE_SIZE > with HOST_PAGE_SIZE which is utterly wrong. Only one of those needs to > be changed, the one passed to ibmvscsi_do_host_config() which is what's > visible to the server, all the rest is just sysfs attributes and should > remain as-is. > > Additionally (not even mentioning that there is no explanation as to > what the real problem is anywhere in the changeset) I don't like the > fix. The root of the problem is that the MAD header has a 16-bit length > field, so writing 0x10000 (64K PAGE_SIZE) into it doesn't quite work. > > So in addition to a better comment, I would suggest a fix more like > this: > > scsi/ibmvscsi: Fix host config length field overflow > > The length field in the host config packet is only 16-bit long, so > passing it 0x10000 (64K which is our standard PAGE_SIZE) doesn't > work and result in an empty config from the server. > > Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > CC: <stable@xxxxxxxxxxxxxxx> Acked-by: Robert Jennings <rcj@xxxxxxxxxxxxxxxxxx> Tested with an IBM i host and confirmed the fix. > --- > > diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c > index 3a6c474..337e8b3 100644 > --- a/drivers/scsi/ibmvscsi/ibmvscsi.c > +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c > @@ -1541,6 +1541,9 @@ static int ibmvscsi_do_host_config(struct ibmvscsi_host_data *hostdata, > > host_config = &evt_struct->iu.mad.host_config; > > + /* The transport length field is only 16-bit */ > + length = min(0xffff, length); > + > /* Set up a lun reset SRP command */ > memset(host_config, 0x00, sizeof(*host_config)); > host_config->common.type = VIOSRP_HOST_CONFIG_TYPE; > > > -- > 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 -- 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
