[ofw] [Patch 15/62] Reference implementation of NDv2

[Fab Tillier]

Implement proper cancel_listen functionality.

The current code will destroy the underlying CEP in cm_cancel_listen, and checks for double-free in kal_cep_destroy.  This is a bit risky because the CEP could be reused and the double-free check not trap this case, freeing the CEP from under a different connection.

This patch adds a new function to the CEP manager to cancel a listen (putting the CEP back to the IDLE state).  This ensures that the CEP is not freed (or reused) before the current client frees it.

Signed-off-by: Fab Tillier <ftillier at microsoft.com>

diff -dwup3 -x *svn* -r c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\core\al\al_cm_cep.h .\core\al\al_cm_cep.h
--- c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\core\al\al_cm_cep.h	Thu May 31 11:22:16 2012
+++ .\core\al\al_cm_cep.h	Wed Jul 25 19:46:03 2012
@@ -142,6 +142,11 @@ al_cep_listen(
 
 #ifdef CL_KERNEL
 ib_api_status_t
+kal_cep_cancel_listen(
+	IN				ib_al_handle_t				h_al,
+	IN				net32_t						cid );
+
+ib_api_status_t
 kal_cep_pre_req(
 	IN				ib_al_handle_t				h_al,
 	IN				net32_t						cid,
diff -dwup3 -x *svn* -r c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\core\al\kernel\al_cm.c .\core\al\kernel\al_cm.c
--- c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\core\al\kernel\al_cm.c	Thu Mar 29 00:15:20 2012
+++ .\core\al\kernel\al_cm.c	Thu Jul 26 15:31:13 2012
@@ -193,13 +193,10 @@ cm_listen(iba_cm_id *p_id, net64_t servi
 	return ib_to_ntstatus(ib_status);
 }
 
-static void
+static NTSTATUS
 cm_cancel_listen(iba_cm_id *p_id)
 {
-	iba_cm_id_priv	*id;
-
-	id = CONTAINING_RECORD(p_id, iba_cm_id_priv, id);
-	kal_cep_destroy(gh_al, p_id->cid, STATUS_SUCCESS);
+	return ib_to_ntstatus(kal_cep_cancel_listen(gh_al, p_id->cid));
 }
 
 static NTSTATUS
diff -dwup3 -x *svn* -r c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\core\al\kernel\al_cm_cep.c .\core\al\kernel\al_cm_cep.c
--- c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\core\al\kernel\al_cm_cep.c	Thu May 31 11:22:15 2012
+++ .\core\al\kernel\al_cm_cep.c	Mon Jul 30 22:23:51 2012
@@ -4195,11 +4195,7 @@ kal_cep_destroy(
 
 	KeAcquireInStackQueuedSpinLock( &gp_cep_mgr->lock, &hdl );
 	p_cep = __lookup_cep( h_al, cid );
-	if(p_cep == NULL || p_cep->state == CEP_STATE_DESTROY)
-    {// kal_cep_destroy was already called - do nothing
-		KeReleaseInStackQueuedSpinLock( &hdl );
-		return;
-    }
+	CL_ASSERT( p_cep );
 
 	context = p_cep->context;
 	pfn_destroy_cb = p_cep->pfn_destroy_cb;
@@ -4221,6 +4217,36 @@ kal_cep_destroy(
 
 
 ib_api_status_t
+kal_cep_cancel_listen(
+	IN				ib_al_handle_t				h_al,
+	IN				net32_t						cid )
+{
+	KLOCK_QUEUE_HANDLE	hdl;
+	kcep_t				*p_cep;
+
+	KeAcquireInStackQueuedSpinLock( &gp_cep_mgr->lock, &hdl );
+	p_cep = __lookup_cep( h_al, cid );
+	if( p_cep == NULL )
+	{
+		KeReleaseInStackQueuedSpinLock( &hdl );
+		return IB_INVALID_HANDLE;
+	}
+
+	cl_atomic_inc( &p_cep->ref_cnt );
+    /*
+     * Note that __cleanup_cep will decrement the ref_cnt.
+     */
+	__cleanup_cep( p_cep );
+    /*
+     * __cleanup_cep flipped the state to DESTROY, move it to IDLE.
+     */
+    p_cep->state = CEP_STATE_IDLE;
+	KeReleaseInStackQueuedSpinLock( &hdl );
+    return STATUS_SUCCESS;
+}
+
+
+ib_api_status_t
 al_cep_listen(
 	IN				ib_al_handle_t				h_al,
 	IN				net32_t						cid,
diff -dwup3 -x *svn* -r c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\inc\kernel\iba\ib_cm_ifc.h .\inc\kernel\iba\ib_cm_ifc.h
--- c:\dev\openib\ofw\gen1\branches\mlx4_30\trunk\inc\kernel\iba\ib_cm_ifc.h	Thu Aug 02 12:47:08 2012
+++ .\inc\kernel\iba\ib_cm_ifc.h	Thu Jul 26 15:31:14 2012
@@ -285,7 +285,7 @@ typedef struct _iba_cm_interface
 
 	NTSTATUS		(*migrate)(iba_cm_id *p_id);
 	NTSTATUS		(*established)(iba_cm_id *p_id);
-	void			(*cancel_listen)(iba_cm_id *p_id);
+	NTSTATUS		(*cancel_listen)(iba_cm_id *p_id);
 }	iba_cm_interface;
 
 static inline USHORT IbaCmVersion(UINT8 Major, UINT8 Minor)
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