[PATCH RESEND v2 11/23] sparc: led: let procfs copy in writes

[Christian Brauner]

Implement ->proc_write_buf() so procfs copies in what is written to
/proc/led before it pins the entry, and parse the command from that
copy. Writes larger than PAGE_SIZE - 1 bytes fail with -EINVAL now.

Signed-off-by: Christian Brauner (Amutable) <brauner@xxxxxxxxxx>
---
 arch/sparc/kernel/led.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/arch/sparc/kernel/led.c b/arch/sparc/kernel/led.c
index 0f7376b51a04..1f244e394207 100644
--- a/arch/sparc/kernel/led.c
+++ b/arch/sparc/kernel/led.c
@@ -60,18 +60,14 @@ static int led_proc_show(struct seq_file *m, void *v)
 	return 0;
 }
 
-static ssize_t led_proc_write(struct file *file, const char __user *buffer,
+static ssize_t led_proc_write(struct file *file, char *buf,
 			      size_t count, loff_t *ppos)
 {
 	size_t len = count;
-	char *buf = NULL;
 
 	if (count > LED_MAX_LENGTH)
 		count = LED_MAX_LENGTH;
-
-	buf = memdup_user_nul(buffer, count);
-	if (IS_ERR(buf))
-		return PTR_ERR(buf);
+	buf[count] = '\0';
 
 	/* work around \n when echo'ing into proc */
 	if (count > 0 && buf[count - 1] == '\n')
@@ -96,14 +92,12 @@ static ssize_t led_proc_write(struct file *file, const char __user *buffer,
 		auxio_set_led(AUXIO_LED_OFF);
 	}
 
-	kfree(buf);
-
 	return len;
 }
 
 static const struct proc_ops led_proc_ops = {
 	.proc_show	= led_proc_show,
-	.proc_write	= led_proc_write,
+	.proc_write_buf	= led_proc_write,
 };
 #endif
 

-- 
2.53.0