From: Thomas Monjalon <redacted>
Date: Monday, 22 November 2021 at 12:23
To: Elena Agostini <redacted>
Cc: dev@dpdk.org <redacted>
Subject: Re: [PATCH v3] gpudev: manage NULL pointer
External email: Use caution opening links or attachments>

22/11/2021 19:24, eagostini@nvidia.com:

quoted

From: Elena Agostini <redacted>

gpudev free and unregister functions return gracefully if input pointer is NULL>

We could add that the API doc was indicating NULL as a no-op accepted value.>

Another explanation to add: cuda driver checks are removed because redundant
with the checks added in gpudev library.>

quoted

Fixes: 818a067baf90 ("gpudev: manage NULL pointer")>

It should be:
Fixes: e818c4e2bf50 ("gpudev: add memory API")>

quoted

Signed-off-by: Elena Agostini <redacted>
---
 drivers/gpu/cuda/cuda.c | 6 ------
 lib/gpudev/gpudev.c     | 6 ++++++
 2 files changed, 6 insertions(+), 6 deletions(-)

[...]

quoted

--- a/lib/gpudev/gpudev.c
+++ b/lib/gpudev/gpudev.c

@@ -569,6 +569,9 @@ rte_gpu_mem_free(int16_t dev_id, void *ptr)
 {
      struct rte_gpu *dev;

+     if (ptr == NULL)
+             return 0;
+
      dev = gpu_get_by_id(dev_id);
      if (dev == NULL) {
              GPU_LOG(ERR, "free mem for invalid device ID %d", dev_id);>

I think we should keep this check first.

Why should gpudev waste more latency in looking for the device if the ptr is NULL?

quoted

@@ -612,6 +615,9 @@ rte_gpu_mem_unregister(int16_t dev_id, void *ptr)
 {
      struct rte_gpu *dev;

+     if (ptr == NULL)
+             return 0;
+
      dev = gpu_get_by_id(dev_id);
      if (dev == NULL) {
              GPU_LOG(ERR, "unregister mem for invalid device ID %d", dev_id);>

Same here.

There is third function where NULL should be accepted: rte_gpu_mem_register>

Thanks, let me add it