diff mbox series

[1/2] 9p/xen: fix version parsing

Message ID 20230130113036.7087-2-jgross@suse.com
State New
Headers
Series 9p/xen: fix 2 issues with connecting to backend |

Commit Message

Juergen Gross Jan. 30, 2023, 11:30 a.m. UTC 
  When connecting the Xen 9pfs frontend to the backend, the "versions"
Xenstore entry written by the backend is parsed in a wrong way.

The "versions" entry is defined to contain the versions supported by
the backend separated by commas (e.g. "1,2"). Today only version "1"
is defined. Unfortunately the frontend doesn't look for "1" being
listed in the entry, but it is expecting the entry to have the value
"1".

This will result in failure as soon as the backend will support e.g.
versions "1" and "2".

Fix that by scanning the entry correctly.

Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend")
Signed-off-by: Juergen Gross <jgross@suse.com>
---
 net/9p/trans_xen.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Comments

Simon Horman Jan. 31, 2023, 6:48 p.m. UTC | #1 
On Mon, Jan 30, 2023 at 12:30:35PM +0100, Juergen Gross wrote:
> When connecting the Xen 9pfs frontend to the backend, the "versions"
> Xenstore entry written by the backend is parsed in a wrong way.
> 
> The "versions" entry is defined to contain the versions supported by
> the backend separated by commas (e.g. "1,2"). Today only version "1"
> is defined. Unfortunately the frontend doesn't look for "1" being
> listed in the entry, but it is expecting the entry to have the value
> "1".
> 
> This will result in failure as soon as the backend will support e.g.
> versions "1" and "2".
> 
> Fix that by scanning the entry correctly.
> 
> Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend")
> Signed-off-by: Juergen Gross <jgross@suse.com>

It's unclear if this series is targeted at 'net' or 'net-next'.
FWIIW, I feel I feel it would be more appropriate for the latter
as these do not feel like bug fixes: feel free to differ on that.

Regardless,

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Juergen Gross Feb. 1, 2023, 6:37 a.m. UTC | #2 
On 31.01.23 19:48, Simon Horman wrote:
> On Mon, Jan 30, 2023 at 12:30:35PM +0100, Juergen Gross wrote:
>> When connecting the Xen 9pfs frontend to the backend, the "versions"
>> Xenstore entry written by the backend is parsed in a wrong way.
>>
>> The "versions" entry is defined to contain the versions supported by
>> the backend separated by commas (e.g. "1,2"). Today only version "1"
>> is defined. Unfortunately the frontend doesn't look for "1" being
>> listed in the entry, but it is expecting the entry to have the value
>> "1".
>>
>> This will result in failure as soon as the backend will support e.g.
>> versions "1" and "2".
>>
>> Fix that by scanning the entry correctly.
>>
>> Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend")
>> Signed-off-by: Juergen Gross <jgross@suse.com>
> 
> It's unclear if this series is targeted at 'net' or 'net-next'.
> FWIIW, I feel I feel it would be more appropriate for the latter
> as these do not feel like bug fixes: feel free to differ on that.

I'm fine with net-next.

Right now there is no problem with the current behavior. This will
change only in case Xen starts to support a new transport version.

For the other patch the problem would show up only if Xen starts
supporting dynamical attach/detach of 9pfs devices, which is not
the case right now.

> 
> Regardless,
> 
> Reviewed-by: Simon Horman <simon.horman@corigine.com>
> 

Thanks,


Juergen
Dominique Martinet Feb. 11, 2023, 12:11 a.m. UTC | #3 
Juergen Gross wrote on Wed, Feb 01, 2023 at 07:37:04AM +0100:
> > It's unclear if this series is targeted at 'net' or 'net-next'.
> > FWIIW, I feel I feel it would be more appropriate for the latter
> > as these do not feel like bug fixes: feel free to differ on that.
> 
> I'm fine with net-next.

It doesn't look like it got picked up in net-next, so I'm queueing it up in the
9p tree.

Thanks for the patches and the review!
diff mbox series

Patch

diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index 82c7005ede65..ad2947a3b376 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -378,13 +378,19 @@  static int xen_9pfs_front_probe(struct xenbus_device *dev,
 	int ret, i;
 	struct xenbus_transaction xbt;
 	struct xen_9pfs_front_priv *priv = NULL;
-	char *versions;
+	char *versions, *v;
 	unsigned int max_rings, max_ring_order, len = 0;
 
 	versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
 	if (IS_ERR(versions))
 		return PTR_ERR(versions);
-	if (strcmp(versions, "1")) {
+	for (v = versions; *v; v++) {
+		if (simple_strtoul(v, &v, 10) == 1) {
+			v = NULL;
+			break;
+		}
+	}
+	if (v) {
 		kfree(versions);
 		return -EINVAL;
 	}