Input: serio_raw - return proper result when serio_raw_read fails

serio_raw_read now returns (sometimes partially) successful number of
bytes transferred to the caller, and only returns error code to the
caller on completely failed transfers.

Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/serio/serio_raw.c b/drivers/input/serio/serio_raw.c
index 8250299fd64ff37d78d97910a702f00710157532..4494233d331ac4689eef8ca58366c7138904627d 100644 (file)
--- a/drivers/input/serio/serio_raw.c
+++ b/drivers/input/serio/serio_raw.c
@@ -164,7 +164,8 @@ static ssize_t serio_raw_read(struct file *file, char __user *buffer,
        struct serio_raw_client *client = file->private_data;
        struct serio_raw *serio_raw = client->serio_raw;
        char uninitialized_var(c);
-       ssize_t retval = 0;
+       ssize_t read = 0;
+       int retval;
 
        if (serio_raw->dead)
                return -ENODEV;
@@ -180,13 +181,15 @@ static ssize_t serio_raw_read(struct file *file, char __user *buffer,
        if (serio_raw->dead)
                return -ENODEV;
 
-       while (retval < count && serio_raw_fetch_byte(serio_raw, &c)) {
-               if (put_user(c, buffer++))
-                       return -EFAULT;
-               retval++;
+       while (read < count && serio_raw_fetch_byte(serio_raw, &c)) {
+               if (put_user(c, buffer++)) {
+                       retval = -EFAULT;
+                       break;
+               }
+               read++;
        }
 
-       return retval;
+       return read ?: retval;
 }
 
 static ssize_t serio_raw_write(struct file *file, const char __user *buffer,