linux-kernel - Re: [PATCH 1/2] staging: greybus: remove unused kfifo

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Message-ID: <881e54df-80bf-bec2-408d-6718c55d403f@nexus-software.ie>
Date:   Fri, 3 Nov 2017 10:28:31 +0000
From:   Bryan O'Donoghue <pure.logic@...us-software.ie>
To:     Arnd Bergmann <arnd@...db.de>, Johan Hovold <johan@...nel.org>,
        Alex Elder <elder@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Viresh Kumar <viresh.kumar@...aro.org>,
        Gioh Kim <gi-oh.kim@...fitbricks.com>,
        Arushi Singhal <arushisinghal19971997@...il.com>,
        Abdul Rauf <abdulraufmujahid@...il.com>,
        greybus-dev@...ts.linaro.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] staging: greybus: remove unused kfifo_ts

On 02/11/17 14:32, Arnd Bergmann wrote:
> As of commit 8e1d6c336d74 ("greybus: loopback: drop bus aggregate
> calculation"), nothing ever reads from kfifo_ts, so there is no
> reason to write to it or even allocate it any more.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>   drivers/staging/greybus/loopback.c | 27 +++------------------------
>   1 file changed, 3 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
> index 08e255884206..85046fb16aad 100644
> --- a/drivers/staging/greybus/loopback.c
> +++ b/drivers/staging/greybus/loopback.c
> @@ -72,7 +72,6 @@ struct gb_loopback {
>   
>   	struct dentry *file;
>   	struct kfifo kfifo_lat;
> -	struct kfifo kfifo_ts;
>   	struct mutex mutex;
>   	struct task_struct *task;
>   	struct list_head entry;
> @@ -262,7 +261,6 @@ static void gb_loopback_check_attr(struct gb_loopback *gb)
>   			 gb->iteration_max, kfifo_depth);
>   	}
>   	kfifo_reset_out(&gb->kfifo_lat);
> -	kfifo_reset_out(&gb->kfifo_ts);
>   
>   	switch (gb->type) {
>   	case GB_LOOPBACK_TYPE_PING:
> @@ -387,13 +385,6 @@ static u64 gb_loopback_calc_latency(struct timeval *ts, struct timeval *te)
>   	return __gb_loopback_calc_latency(t1, t2);
>   }
>   
> -static void gb_loopback_push_latency_ts(struct gb_loopback *gb,
> -					struct timeval *ts, struct timeval *te)
> -{
> -	kfifo_in(&gb->kfifo_ts, (unsigned char *)ts, sizeof(*ts));
> -	kfifo_in(&gb->kfifo_ts, (unsigned char *)te, sizeof(*te));
> -}
> -
>   static int gb_loopback_operation_sync(struct gb_loopback *gb, int type,
>   				      void *request, int request_size,
>   				      void *response, int response_size)
> @@ -433,7 +424,6 @@ static int gb_loopback_operation_sync(struct gb_loopback *gb, int type,
>   	do_gettimeofday(&te);
>   
>   	/* Calculate the total time the message took */
> -	gb_loopback_push_latency_ts(gb, &ts, &te);
>   	gb->elapsed_nsecs = gb_loopback_calc_latency(&ts, &te);
>   
>   out_put_operation:
> @@ -521,11 +511,9 @@ static void gb_loopback_async_operation_callback(struct gb_operation *operation)
>   				err = true;
>   	}
>   
> -	if (!err) {
> -		gb_loopback_push_latency_ts(gb, &op_async->ts, &te);
> +	if (!err)
>   		gb->elapsed_nsecs = gb_loopback_calc_latency(&op_async->ts,
>   							     &te);
> -	}
>   
>   	if (op_async->pending) {
>   		if (err)
> @@ -1241,18 +1229,12 @@ static int gb_loopback_probe(struct gb_bundle *bundle,
>   		retval = -ENOMEM;
>   		goto out_conn;
>   	}
> -	if (kfifo_alloc(&gb->kfifo_ts, kfifo_depth * sizeof(struct timeval) * 2,
> -			  GFP_KERNEL)) {
> -		retval = -ENOMEM;
> -		goto out_kfifo0;
> -	}
> -
>   	/* Fork worker thread */
>   	mutex_init(&gb->mutex);
>   	gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
>   	if (IS_ERR(gb->task)) {
>   		retval = PTR_ERR(gb->task);
> -		goto out_kfifo1;
> +		goto out_kfifo;
>   	}
>   
>   	spin_lock_irqsave(&gb_dev.lock, flags);
> @@ -1266,9 +1248,7 @@ static int gb_loopback_probe(struct gb_bundle *bundle,
>   
>   	return 0;
>   
> -out_kfifo1:
> -	kfifo_free(&gb->kfifo_ts);
> -out_kfifo0:
> +out_kfifo:
>   	kfifo_free(&gb->kfifo_lat);
>   out_conn:
>   	device_unregister(dev);
> @@ -1302,7 +1282,6 @@ static void gb_loopback_disconnect(struct gb_bundle *bundle)
>   		kthread_stop(gb->task);
>   
>   	kfifo_free(&gb->kfifo_lat);
> -	kfifo_free(&gb->kfifo_ts);
>   	gb_connection_latency_tag_disable(gb->connection);
>   	debugfs_remove(gb->file);
>   
> 

This looks right to me

Reviewed-by: Bryan O'Donoghue <pure.logic@...us-software.ie>