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SubjectRe: [PATCH v3 07/28] IB/Verbs: Reform IB-ulp ipoib
On Mon, Apr 13, 2015 at 02:01:38PM -0600, Jason Gunthorpe wrote:
> On Mon, Apr 13, 2015 at 03:46:03PM -0400, ira.weiny wrote:
>
> > > This doesn't quite look right, it should be 'goto error1'
> >
> > Looks like you replied to the wrong patch. ?? I don't see error1 in ipoib_add_one.
>
> > For the ib_cm module...
>
> Right, sorry.
>
> > Yes I think it should go to "error1". However, see below...
> >
> > This is the type of clean up error which would be avoided if a call to
> > cap_ib_cm_dev() were done at the top of the function.
>
> So what does cap_ib_cm_dev return in your example:

I was thinking it was all or nothing. But I see now that the cap_ib_cm_dev is
actually true if "any" port supports the CM.

> > Dev
> > port 1 : cap_is_cm == true
> > port 2 : cap_is_cm == false
> > port 3 : cap_is_cm == true
>
> True? Then the code is still broken, having cap_ib_cm_dev doesn't help
> anything.

I see that now.

>
> If we make it possible to be per port then it has to be fixed.

Yes

>
> If you want to argue the above example is illegal and port 2 has to be
> on a different device, I'd be interested to see what that looks like.

I think the easiest fix for this series is to add this to the final CM code
(applies after the end of the series compile tested only):

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 63418ee..0d0fc24 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -3761,7 +3761,11 @@ static void cm_add_one(struct ib_device *ib_device)
unsigned long flags;
int ret;
u8 i;
- int count = 0;
+
+ for (i = 1; i <= ib_device->phys_port_cnt; i++) {
+ if (!cap_ib_cm(ib_device, i))
+ return;
+ }

cm_dev = kzalloc(sizeof(*cm_dev) + sizeof(*port) *
ib_device->phys_port_cnt, GFP_KERNEL);
@@ -3810,14 +3814,6 @@ static void cm_add_one(struct ib_device *ib_device)
ret = ib_modify_port(ib_device, i, 0, &port_modify);
if (ret)
goto error3;
-
- count++;
- }
-
- if (!count) {
- device_unregister(cm_dev->device);
- kfree(cm_dev);
- return;
}

ib_set_client_data(ib_device, &cm_client, cm_dev);

>
> Thinking about it some more, cap_foo_dev only makes sense if all ports
> are either true or false. Mixed is a BUG.

Agree

After more thought and reading other opinions, I must agree we should not
have cap_foo_dev.

For the CM case which has some need to support itself device device wide what
about this patch (compile tested only):


10:03:57 > git di
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 4b083f5..7347445 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -1639,7 +1639,7 @@ static void cma_listen_on_dev(struct rdma_id_private
*id_priv,
struct rdma_cm_id *id;
int ret;

- if (cma_family(id_priv) == AF_IB && !cap_ib_cm_dev(cma_dev->device))
+ if (cma_family(id_priv) == AF_IB && !cap_ib_cm_any_port(cma_dev->device))
return;

id = rdma_create_id(cma_listen_handler, id_priv, id_priv->id.ps,
@@ -2030,7 +2030,7 @@ static int cma_bind_loopback(struct rdma_id_private
*id_priv)
mutex_lock(&lock);
list_for_each_entry(cur_dev, &dev_list, list) {
if (cma_family(id_priv) == AF_IB &&
- !cap_ib_cm_dev(cur_dev->device))
+ !cap_ib_cm_any_port(cur_dev->device))
continue;

if (!cma_dev)
diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 065405e..dc4caae 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -1253,7 +1253,7 @@ static void ib_ucm_add_one(struct ib_device *device)
dev_t base;
struct ib_ucm_device *ucm_dev;

- if (!device->alloc_ucontext || !cap_ib_cm_dev(device))
+ if (!device->alloc_ucontext || !cap_ib_cm_any_port(device))
return;

ucm_dev = kzalloc(sizeof *ucm_dev, GFP_KERNEL);
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 3cc3f53..a8fa1f5 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1920,15 +1920,14 @@ static inline int cap_read_multi_sge(struct ib_device
*device, u8 port_num)
}

/**
- * cap_ib_cm_dev - Check if any port of device has the capability Infiniband
- * Communication Manager.
+ * cap_ib_cm_any_port - Check if any port of the device has Infiniband
+ * Communication Manager (CM) support.
*
* @device: Device to be checked
*
- * Return 0 when all port of the device don't support Infiniband
- * Communication Manager.
+ * Return 1 if any port of the device supports the IB CM.
*/
-static inline int cap_ib_cm_dev(struct ib_device *device)
+static inline int cap_ib_cm_any_port(struct ib_device *device)
{
int i;

>
> That seems reasonable, and solves the #10 problem, but we should
> enforce this invariant during device register.
>
> Typically the ports seem to be completely orthogonal (like SA), so in those
> cases the _dev and restriction makes no sense.

While the ports in ib_sa and ib_umad probably can be orthogonal the current
implementation does not support that and this patch series obscures that a bit.

>
> CM seems to be different, so it should probably enforce its rules

Technically, the implementation of the ib_sa and ib_umad modules are not
different it is just that Michaels patch is not broken.
I'm not saying we can't change the ib_sa and ib_umad modules but the current
logic is all or nothing. And I think changing this :

1) require more review and testing
2) is not the purpose of this series.

Ira

>
> Jason


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