n Wed, 2012-07-18 at 18:49 +0200, o...@aepfle.de wrote:
> From: Linda Xie <lx...@us.ibm.com>
>
> 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 <b...@kernel.crashing.org>
CC: <sta...@vger.kernel.org>
---
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;
--
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