linux-kernel - [PATCH v2] staging: most: dim2: read done_buffers count locally from HDM channel

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Date:   Tue, 18 Oct 2022 12:48:13 +0530
From:   Deepak R Varma <drv@...lo.com>
To:     outreachy@...ts.linux.dev, gregkh@...uxfoundation.org,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Cc:     kumarpraveen@...ux.microsoft.com, saurabh.truth@...il.com
Subject: [PATCH v2] staging: most: dim2: read done_buffers count locally from
 HDM channel

The done_buffer count is already available in the hdm_channel struct.
Calling dim_get_channel_state function to source this value out of
the same structure is unnecessary.
Further, the second parameter struct dim_ch_state_t to this function
is filled by using the hdm_channel inside the function. This filled in
variable is never used in the caller and can be altogether removed.
So, a call to dim_get_channel_state function in this context also
deems expensive.

Signed-off-by: Deepak R Varma <drv@...lo.com>
---
Changes in v2:
   1. Update patch log message to be more descriptive about the reason for change.
      Feedback provided by julia.lawall@...ia.fr

PLEASE NOTE: I have only built the module on my machine, but have not tested it.
I am not sure how to test this change. I am willing to test it with appropriate
guidance provided I have the necessary hardware.

 drivers/staging/most/dim2/dim2.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/most/dim2/dim2.c b/drivers/staging/most/dim2/dim2.c
index ab72e11ac5ab..4c1f27898a29 100644
--- a/drivers/staging/most/dim2/dim2.c
+++ b/drivers/staging/most/dim2/dim2.c
@@ -259,7 +259,6 @@ static void retrieve_netinfo(struct dim2_hdm *dev, struct mbo *mbo)
 static void service_done_flag(struct dim2_hdm *dev, int ch_idx)
 {
 	struct hdm_channel *hdm_ch = dev->hch + ch_idx;
-	struct dim_ch_state_t st;
 	struct list_head *head;
 	struct mbo *mbo;
 	int done_buffers;
@@ -271,7 +270,7 @@ static void service_done_flag(struct dim2_hdm *dev, int ch_idx)

 	spin_lock_irqsave(&dim_lock, flags);

-	done_buffers = dim_get_channel_state(&hdm_ch->ch, &st)->done_buffers;
+	done_buffers = hdm_ch->ch.done_sw_buffers_number;
 	if (!done_buffers) {
 		spin_unlock_irqrestore(&dim_lock, flags);
 		return;
--
2.30.2