linux-kernel - [PATCH 2/2] media: go7007: remove redundant initialization

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Message-Id: <dc1bd4f8df4e07263e7c3ff7e1853ee3dec95df8.1624217907.git.paskripkin@gmail.com>
Date:   Sun, 20 Jun 2021 22:45:42 +0300
From:   Pavel Skripkin <paskripkin@...il.com>
To:     hverkuil-cisco@...all.nl, mchehab@...nel.org, oneukum@...e.com,
        gregkh@...e.de
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-kernel-mentees@...ts.linuxfoundation.org,
        Pavel Skripkin <paskripkin@...il.com>
Subject: [PATCH 2/2] media: go7007: remove redundant initialization

In go7007_alloc() kzalloc() is used for struct go7007
allocation. It means that there is no need in zeroing
any members, because kzalloc will take care of it.

Removing these reduntant initialization steps increases
execution speed a lot:

	Before:
		+ 86.802 us   |    go7007_alloc();
	After:
		+ 29.595 us   |    go7007_alloc();

Fixes: 866b8695d67e8 ("Staging: add the go7007 video driver")
Signed-off-by: Pavel Skripkin <paskripkin@...il.com>
---
 drivers/media/usb/go7007/go7007-driver.c | 26 ------------------------
 1 file changed, 26 deletions(-)

diff --git a/drivers/media/usb/go7007/go7007-driver.c b/drivers/media/usb/go7007/go7007-driver.c
index f1767be9d868..6650eab913d8 100644
--- a/drivers/media/usb/go7007/go7007-driver.c
+++ b/drivers/media/usb/go7007/go7007-driver.c
@@ -691,49 +691,23 @@ struct go7007 *go7007_alloc(const struct go7007_board_info *board,
 						struct device *dev)
 {
 	struct go7007 *go;
-	int i;
 
 	go = kzalloc(sizeof(struct go7007), GFP_KERNEL);
 	if (go == NULL)
 		return NULL;
 	go->dev = dev;
 	go->board_info = board;
-	go->board_id = 0;
 	go->tuner_type = -1;
-	go->channel_number = 0;
-	go->name[0] = 0;
 	mutex_init(&go->hw_lock);
 	init_waitqueue_head(&go->frame_waitq);
 	spin_lock_init(&go->spinlock);
 	go->status = STATUS_INIT;
-	memset(&go->i2c_adapter, 0, sizeof(go->i2c_adapter));
-	go->i2c_adapter_online = 0;
-	go->interrupt_available = 0;
 	init_waitqueue_head(&go->interrupt_waitq);
-	go->input = 0;
 	go7007_update_board(go);
-	go->encoder_h_halve = 0;
-	go->encoder_v_halve = 0;
-	go->encoder_subsample = 0;
 	go->format = V4L2_PIX_FMT_MJPEG;
 	go->bitrate = 1500000;
 	go->fps_scale = 1;
-	go->pali = 0;
 	go->aspect_ratio = GO7007_RATIO_1_1;
-	go->gop_size = 0;
-	go->ipb = 0;
-	go->closed_gop = 0;
-	go->repeat_seqhead = 0;
-	go->seq_header_enable = 0;
-	go->gop_header_enable = 0;
-	go->dvd_mode = 0;
-	go->interlace_coding = 0;
-	for (i = 0; i < 4; ++i)
-		go->modet[i].enable = 0;
-	for (i = 0; i < 1624; ++i)
-		go->modet_map[i] = 0;
-	go->audio_deliver = NULL;
-	go->audio_enabled = 0;
 
 	return go;
 }
-- 
2.32.0