Bluetooth: Collect kcov coverage from hci_rx_work

Annotate hci_rx_work() with kcov_remote_start() and kcov_remote_stop()
calls, so remote KCOV coverage is collected while processing the rx_q
queue which is the main incoming Bluetooth packet queue.

Coverage is associated with the thread which created the packet skb.

Signed-off-by: Tamas Koczka <poprdi@google.com>
---
 net/bluetooth/hci_core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

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Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=642289

---Test result---

Test Summary:
CheckPatch                    PASS      1.52 seconds
GitLint                       PASS      0.98 seconds
SubjectPrefix                 PASS      0.90 seconds
BuildKernel                   PASS      30.85 seconds
BuildKernel32                 PASS      27.42 seconds
Incremental Build with patchesPASS      38.41 seconds
TestRunner: Setup             PASS      466.08 seconds
TestRunner: l2cap-tester      PASS      17.39 seconds
TestRunner: bnep-tester       PASS      6.12 seconds
TestRunner: mgmt-tester       PASS      101.74 seconds
TestRunner: rfcomm-tester     PASS      9.64 seconds
TestRunner: sco-tester        PASS      9.45 seconds
TestRunner: smp-tester        PASS      9.42 seconds
TestRunner: userchan-tester   PASS      6.32 seconds



---
Regards,
Linux Bluetooth

Hello Everyone,

Thank you for reviewing the patch - I hope everything is going well.

Please feel free to ask me if you need any more information regarding it!

Thank you,
Tamas

On Tue, May 17, 2022 at 11:45 AM Tamas Koczka <poprdi@google.com> wrote:
>
> Annotate hci_rx_work() with kcov_remote_start() and kcov_remote_stop()
> calls, so remote KCOV coverage is collected while processing the rx_q
> queue which is the main incoming Bluetooth packet queue.
>
> Coverage is associated with the thread which created the packet skb.
>
> Signed-off-by: Tamas Koczka <poprdi@google.com>
> ---
>  net/bluetooth/hci_core.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 45c2dd2e1590..703722031b8d 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -29,6 +29,7 @@
>  #include <linux/rfkill.h>
>  #include <linux/debugfs.h>
>  #include <linux/crypto.h>
> +#include <linux/kcov.h>
>  #include <linux/property.h>
>  #include <linux/suspend.h>
>  #include <linux/wait.h>
> @@ -3780,7 +3781,9 @@ static void hci_rx_work(struct work_struct *work)
>
>         BT_DBG("%s", hdev->name);
>
> -       while ((skb = skb_dequeue(&hdev->rx_q))) {
> +       for (; (skb = skb_dequeue(&hdev->rx_q)); kcov_remote_stop()) {
> +               kcov_remote_start_common(skb_get_kcov_handle(skb));
> +
>                 /* Send copy to monitor */
>                 hci_send_to_monitor(hdev, skb);
>
> --
> 2.36.0.550.gb090851708-goog
>

Hi Tamas,

> Annotate hci_rx_work() with kcov_remote_start() and kcov_remote_stop()
> calls, so remote KCOV coverage is collected while processing the rx_q
> queue which is the main incoming Bluetooth packet queue.
> 
> Coverage is associated with the thread which created the packet skb.
> 
> Signed-off-by: Tamas Koczka <poprdi@google.com>
> ---
> net/bluetooth/hci_core.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 45c2dd2e1590..703722031b8d 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -29,6 +29,7 @@
> #include <linux/rfkill.h>
> #include <linux/debugfs.h>
> #include <linux/crypto.h>
> +#include <linux/kcov.h>
> #include <linux/property.h>
> #include <linux/suspend.h>
> #include <linux/wait.h>
> @@ -3780,7 +3781,9 @@ static void hci_rx_work(struct work_struct *work)
> 
> 	BT_DBG("%s", hdev->name);
> 
> -	while ((skb = skb_dequeue(&hdev->rx_q))) {
> +	for (; (skb = skb_dequeue(&hdev->rx_q)); kcov_remote_stop()) {
> +		kcov_remote_start_common(skb_get_kcov_handle(skb));
> +
> 		/* Send copy to monitor */
> 		hci_send_to_monitor(hdev, skb);

patch looks good, but do you mind adding a comment above on why this is done. I asked, because next time around I look at this code I have forgotten all about it. Thanks.

Regards

Marcel