[EMAIL PROTECTED] wrote on Thu, 03 Jul 2008 15:44 -0500:
> Pete Wyckoff wrote:
>> [EMAIL PROTECTED] wrote on Thu, 03 Jul 2008 13:03 -0700:
>>
>>>> That makes sense. I couldn't find anyway to get that bit
>>>> IWCM_F_CONNECT_WAIT cleared (without massive layering violations).
>>>> Is there anything like rdma_give_up_on_the_connect() that works
>>>> on the client side? Am I expected just to wait for the transport
>>>> layer to time out the connect? I could imagine a Ctrl-C situation
>>>> where immediate client-side cancellation is desired.
>>>>
>>> From the perspective of the rdma_cm interface, rdma_destroy_id() is
>>> intended to provide this functionality.
>>>
>>
>> That is a sensible approach. The implementation in iwcm.c just
>> passively waits for a connection to time out before allowing
>> rdma_destroy_id() to complete. Maybe I should look at adding a case
>> in cma_cancel_operation() for CMA_CONNECT that calls into a
>> device-specific function that can actively quit the connection.
>>
>> Or should this be a special case in iwcm's destroy_cm_id()? Where
>> a CONN_SENT state will bypass the check on IWCM_F_CONNECT_WAIT, and
>> call into a device function that tries to cancel the connection
>> attepmt first?
>
> If we define a method that every iwarp provider supports to cancel a
> connect attempt, then we can do away with the IWCM_F_CONNECT_WAIT bit
> altogether and always cancel the operation instead. For cxgb3, the
> connect request to the HW really cannot be canceled. So the driver
> would have to keep its endpoint struct around until the HW finally posts
> the connect attempt results, but mark the endpoint as "no cm_id
> attached". The if the connection succeeds, the driver will immediately
> reset it I guess...
This defines an optional iwcm method that cancels the connect
operation if the device supports that. Otherwise it will wait
on the CONNECT_WAIT bit as usual. Doing it like this does not require
changes in existing devices. It would not be pretty to implement
a mandatory connect_cancel() as you describe for cxgb3.
(I dropped the first-attempt patch in this thread.)
-- Pete
iwcm: connect cancel
Add an interface to cancel a connection attempt. Used on the client side
of rdmacm to cancel a connection, for devices that support such an
operation. This can avoid waiting for the device to timeout the operation
itself.
Signed-off-by: Pete Wyckoff <[EMAIL PROTECTED]>
---
drivers/infiniband/core/iwcm.c | 14 ++++++++++++++
include/rdma/iw_cm.h | 2 ++
2 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
index 81c9195..56aa0d6 100644
--- a/drivers/infiniband/core/iwcm.c
+++ b/drivers/infiniband/core/iwcm.c
@@ -327,6 +327,20 @@ static void destroy_cm_id(struct iw_cm_id *cm_id)
int ret;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+
+ /*
+ * Give the device a chance to cancel the connect, if possible.
+ * Else we wait until it times out.
+ */
+ if (cm_id_priv->state == IW_CM_STATE_CONN_SENT &&
+ cm_id->device->iwcm->connect_cancel) {
+ ret = cm_id->device->iwcm->connect_cancel(cm_id);
+ if (ret == 0) {
+ clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+ cm_id_priv->state = IW_CM_STATE_IDLE;
+ }
+ }
+
/*
* Wait if we're currently in a connect or accept downcall. A
* listening endpoint should never block here.
diff --git a/include/rdma/iw_cm.h b/include/rdma/iw_cm.h
index aeefa9b..046690c 100644
--- a/include/rdma/iw_cm.h
+++ b/include/rdma/iw_cm.h
@@ -119,6 +119,8 @@ struct iw_cm_verbs {
int (*connect)(struct iw_cm_id *cm_id,
struct iw_cm_conn_param *conn_param);
+ int (*connect_cancel)(struct iw_cm_id *cm_id);
+
int (*accept)(struct iw_cm_id *cm_id,
struct iw_cm_conn_param *conn_param);
--
1.5.5.1
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