drm/amdkfd: Validate PeerDirect support on process registration v2

v2: Call kfd_close_peer_direct() if failed to initialize
PeerDirect interface to clean-up resources if any

Network stack could be loaded later so PeerDirect interface may be
not available during amdkfd initialization. Added logic to validate
PeerDirect API presence when HSA process is created.

Change-Id: Ib39b86a0086e2102baa3f41ba2bbb2f3e9a2017f
Signed-off-by: Serguei Sagalovitch <Serguei.Sagalovitch@amd.com>

drivers/gpu/drm/amd/amdkfd/kfd_module.c

@@ -137,8 +137,7 @@ static int __init kfd_module_init(void)
 
 	amdkfd_init_completed = 1;
 
-	if (!kfd_init_peer_direct())
-		pr_info("PeerDirect support was enabled\n");
+	kfd_init_peer_direct();
 
 	dev_info(kfd_device, "Initialized module\n");
 

drivers/gpu/drm/amd/amdkfd/kfd_peerdirect.c

@@ -49,6 +49,8 @@
 #include <linux/slab.h>
 #include <linux/scatterlist.h>
 #include <linux/module.h>
+
+#include "kfd_priv.h"
 #include "amd_rdma.h"
 
 
@@ -428,11 +430,21 @@ static struct peer_memory_client amd_mem_client = {
 	.release = amd_release,
 };
 
-
-int kfd_init_peer_direct(void)
+/** Initialize PeerDirect interface with RDMA Network stack.
+ *
+ *  Because network stack could potentially be loaded later we check
+ *  presence of PeerDirect when HSA process is created. If PeerDirect was
+ *  already initialized we do nothing otherwise try to detect and register.
+ */
+void kfd_init_peer_direct(void)
 {
 	int result;
 
+	if (pfn_ib_unregister_peer_memory_client) {
+		pr_debug("PeerDirect support was already initialized\n");
+		return;
+	}
+
 	pr_debug("Try to initialize PeerDirect support\n");
 
 	pfn_ib_register_peer_memory_client =
@@ -446,15 +458,17 @@ int kfd_init_peer_direct(void)
 	if (!pfn_ib_register_peer_memory_client ||
 		!pfn_ib_unregister_peer_memory_client) {
 		pr_warn("amdkfd: PeerDirect interface was not detected\n");
-		return -EINVAL;
+		/* Do cleanup */
+		kfd_close_peer_direct();
+		return;
 	}
 
 	result = amdkfd_query_rdma_interface(&rdma_interface);
 
 	if (result < 0) {
 		pr_err("amdkfd: Cannot get RDMA Interface (result = %d)\n",
 				result);
-		return result;
+		return;
 	}
 
 	strcpy(amd_mem_client.name,    AMD_PEER_BRIDGE_DRIVER_NAME);
@@ -465,13 +479,19 @@ int kfd_init_peer_direct(void)
 
 	if (!ib_reg_handle) {
 		pr_err("amdkfd: Cannot register peer memory client\n");
-		return -EINVAL;
+		/* Do cleanup */
+		kfd_close_peer_direct();
+		return;
 	}
 
 	pr_info("amdkfd: PeerDirect support was initialized successfully\n");
-	return 0;
+	return;
 }
 
+/**
+ * Close connection with PeerDirect interface with RDMA Network stack.
+ *
+ */
 void kfd_close_peer_direct(void)
 {
 	if (pfn_ib_unregister_peer_memory_client) {
@@ -484,5 +504,10 @@ void kfd_close_peer_direct(void)
 	if (pfn_ib_register_peer_memory_client)
 		symbol_put(ib_register_peer_memory_client);
 
+
+	/* Reset pointers to be safe */
+	pfn_ib_unregister_peer_memory_client = NULL;
+	pfn_ib_register_peer_memory_client   = NULL;
+	ib_reg_handle = NULL;
 }
 

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

@@ -966,7 +966,7 @@ int dbgdev_wave_reset_wavefronts(struct kfd_dev *dev, struct kfd_process *p);
 #define KFD_CWSR_CZ_FW_VER 625
 
 /* PeerDirect support */
-int kfd_init_peer_direct(void);
+void kfd_init_peer_direct(void);
 void kfd_close_peer_direct(void);
 
 /* Debugfs */

drivers/gpu/drm/amd/amdkfd/kfd_process.c

@@ -555,6 +555,12 @@ static struct kfd_process *create_process(const struct task_struct *thread,
 
 	INIT_WORK(&process->eviction_work.work, kfd_evict_bo_worker);
 	INIT_DELAYED_WORK(&process->restore_work, kfd_restore_bo_worker);
+
+	/* If PeerDirect interface was not detected try to detect it again
+	* in case if network driver was loaded later.
+	*/
+	kfd_init_peer_direct();
+
 	return process;
 
 err_init_cwsr: