Re: [PATCH bpf-next v2 03/28] HID: hook up with bpf

On Fri, Mar 4, 2022 at 9:31 AM Benjamin Tissoires benjamin.tissoires@redhat.com wrote:

Now that BPF can be compatible with HID, add the capability into HID. drivers/hid/hid-bpf.c takes care of the glue between bpf and HID, and hid-core can then inject any incoming event from the device into a BPF program to filter/analyze it.

Signed-off-by: Benjamin Tissoires benjamin.tissoires@redhat.com

[...]

+static int hid_bpf_link_attach(struct hid_device *hdev, enum bpf_hid_attach_type type) +{

•   int err = 0;
  

•   switch (type) {
  

•   case BPF_HID_ATTACH_DEVICE_EVENT:
  

•           if (!hdev->bpf.ctx) {
  

•                   hdev->bpf.ctx = bpf_hid_allocate_ctx(hdev, HID_BPF_MAX_BUFFER_SIZE);
  

•                   if (IS_ERR(hdev->bpf.ctx)) {
  

•                           err = PTR_ERR(hdev->bpf.ctx);
  

•                           hdev->bpf.ctx = NULL;
  

•                   }
  

•           }
  

•           break;
  

•   default:
  

•           /* do nothing */
  

Do we need to show warning and/or return EINVAL here?

•   }
  

•   return err;
  

+}

+static void hid_bpf_array_detached(struct hid_device *hdev, enum bpf_hid_attach_type type) +{

•   switch (type) {
  

•   case BPF_HID_ATTACH_DEVICE_EVENT:
  

•           kfree(hdev->bpf.ctx);
  

•           hdev->bpf.ctx = NULL;
  

•           break;
  

•   default:
  

•           /* do nothing */
  

ditto

[...]