Re: [PATCH v2 for-next 05/17] RDMA/bnxt_re: Enhance the existing functions that wait for FW responses

[Leon Romanovsky <leon@kernel.org>]

On Fri, Jun 09, 2023 at 04:01:42AM -0700, Selvin Xavier wrote:
> From: Kashyap Desai <kashyap.desai@broadcom.com>
> 
> Use jiffies based timewait instead of counting iteration for
> commands that block for FW response.
> 
> Also add a poll routine for control path commands. This is for
> polling completion if the waiting commands timeout. This avoids cases
> where the driver misses completion interrupts.
> 
> Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
> Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
> ---
>  drivers/infiniband/hw/bnxt_re/qplib_rcfw.c | 65 +++++++++++++++++++++++-------
>  1 file changed, 51 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
> index 66121fb..3b242cc 100644
> --- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
> +++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
> @@ -53,37 +53,74 @@
>  
>  static void bnxt_qplib_service_creq(struct tasklet_struct *t);
>  
> -/* Hardware communication channel */
> +/**
> + * __wait_for_resp   -	Don't hold the cpu context and wait for response
> + * @rcfw      -   rcfw channel instance of rdev
> + * @cookie    -   cookie to track the command
> + *
> + * Wait for command completion in sleepable context.
> + *
> + * Returns:
> + * 0 if command is completed by firmware.
> + * Non zero error code for rest of the case.

I don't see "return ret;" in this function.

> + */
>  static int __wait_for_resp(struct bnxt_qplib_rcfw *rcfw, u16 cookie)
>  {
>  	struct bnxt_qplib_cmdq_ctx *cmdq;
>  	u16 cbit;
> -	int rc;
> +	int ret;
>  
>  	cmdq = &rcfw->cmdq;
>  	cbit = cookie % rcfw->cmdq_depth;
> -	rc = wait_event_timeout(cmdq->waitq,
> -				!test_bit(cbit, cmdq->cmdq_bitmap),
> -				msecs_to_jiffies(RCFW_CMD_WAIT_TIME_MS));
> -	return rc ? 0 : -ETIMEDOUT;
> +
> +	do {
> +		/* Non zero means command completed */
> +		ret = wait_event_timeout(cmdq->waitq,
> +					 !test_bit(cbit, cmdq->cmdq_bitmap),
> +					 msecs_to_jiffies(10000));

Don't you need to check ret here?

> +
> +		if (!test_bit(cbit, cmdq->cmdq_bitmap))
> +			return 0;
> +
> +		bnxt_qplib_service_creq(&rcfw->creq.creq_tasklet);
> +
> +		if (!test_bit(cbit, cmdq->cmdq_bitmap))
> +			return 0;
> +
> +	} while (true);
>  };
>  
> +/**
> + * __block_for_resp   -	hold the cpu context and wait for response
> + * @rcfw      -   rcfw channel instance of rdev
> + * @cookie    -   cookie to track the command
> + *
> + * This function will hold the cpu (non-sleepable context) and
> + * wait for command completion. Maximum holding interval is 8 second.
> + *
> + * Returns:
> + * -ETIMEOUT if command is not completed in specific time interval.
> + * 0 if command is completed by firmware.
> + */
>  static int __block_for_resp(struct bnxt_qplib_rcfw *rcfw, u16 cookie)
>  {
> -	u32 count = RCFW_BLOCKED_CMD_WAIT_COUNT;
> -	struct bnxt_qplib_cmdq_ctx *cmdq;
> +	struct bnxt_qplib_cmdq_ctx *cmdq = &rcfw->cmdq;
> +	unsigned long issue_time = 0;
>  	u16 cbit;
>  
> -	cmdq = &rcfw->cmdq;
>  	cbit = cookie % rcfw->cmdq_depth;
> -	if (!test_bit(cbit, cmdq->cmdq_bitmap))
> -		goto done;
> +	issue_time = jiffies;
> +
>  	do {
>  		udelay(1);
> +
>  		bnxt_qplib_service_creq(&rcfw->creq.creq_tasklet);
> -	} while (test_bit(cbit, cmdq->cmdq_bitmap) && --count);
> -done:
> -	return count ? 0 : -ETIMEDOUT;
> +		if (!test_bit(cbit, cmdq->cmdq_bitmap))
> +			return 0;
> +
> +	} while (time_before(jiffies, issue_time + (8 * HZ)));
> +
> +	return -ETIMEDOUT;
>  };
>  
>  static int __send_message(struct bnxt_qplib_rcfw *rcfw,
> -- 
> 2.5.5
>