[PATCH 1/2 RESEND] staging: dgnc: remove redundant NULL checks in

[Daeseok Youn <daeseok.youn@gmail.com>]

The dgnc_block_til_ready() is only used in dgnc_tty_open().
The unit data(struct un_t) was stored into tty->driver_data in dgnc_tty_open().
And also tty and un were tested about NULL so these variables doesn't
need to check for NULL in dgnc_block_til_ready().

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
---
RESEND: more explanation about this patch.
origin patch : https://lkml.org/lkml/2016/5/4/12

 drivers/staging/dgnc/dgnc_tty.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/dgnc/dgnc_tty.c b/drivers/staging/dgnc/dgnc_tty.c
index a505775..cff34d4 100644
--- a/drivers/staging/dgnc/dgnc_tty.c
+++ b/drivers/staging/dgnc/dgnc_tty.c
@@ -1172,17 +1172,12 @@ static int dgnc_block_til_ready(struct tty_struct *tty,
 				struct channel_t *ch)
 {
 	int retval = 0;
-	struct un_t *un = NULL;
+	struct un_t *un = tty->driver_data;
 	unsigned long flags;
 	uint	old_flags = 0;
 	int	sleep_on_un_flags = 0;
 
-	if (!tty || tty->magic != TTY_MAGIC || !file || !ch ||
-	    ch->magic != DGNC_CHANNEL_MAGIC)
-		return -ENXIO;
-
-	un = tty->driver_data;
-	if (!un || un->magic != DGNC_UNIT_MAGIC)
+	if (!file)
 		return -ENXIO;
 
 	spin_lock_irqsave(&ch->ch_lock, flags);
-- 
2.8.2