linux-kernel - [PATCH] gpio: mockup: use simple_read_from

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Date:   Thu, 28 Mar 2019 12:00:43 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH] gpio: mockup: use simple_read_from_buffer() in debugfs read callback

From: Bartosz Golaszewski <bgolaszewski@...libre.com>

Calling read() for a single byte read will return 2 currently. Use
simple_read_from_buffer() which correctly handles all sizes.

Fixes: 2a9e27408e12 ("gpio: mockup: rework debugfs interface")
Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
---
 drivers/gpio/gpio-mockup.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 74ba8b1d71d8..859585dce5c9 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -219,12 +219,7 @@ static ssize_t gpio_mockup_debugfs_read(struct file *file,
 	val = gpio_mockup_get(gc, priv->offset);
 	cnt = snprintf(buf, sizeof(buf), "%d\n", val);
 
-	rv = copy_to_user(usr_buf, buf, cnt);
-	if (rv)
-		return rv;
-
-	*ppos += cnt;
-	return cnt;
+	return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt);
 }
 
 static ssize_t gpio_mockup_debugfs_write(struct file *file,
-- 
2.21.0