On Fri, Apr 10, 2015 at 05:48:54PM +0300, Giedrius Statkevičius wrote:
> Remove the dead code protected by in_user in dgnc_tty_write() because it is 
> set
> to 0 and never changed to 1 thus the code in ifs never gets executed.
dgnc_tty_write() is being called by dgnc_tty_put_char() and it is also
the write callback function of struct tty_operations, so I think the
correct fix will be to use from_user and make it 0 when
dgnc_tty_put_char() calls this function else make it 1 to inform the
function that the data wil be coming from the userspace. Maybe some
thing like this:

diff --git a/drivers/staging/dgnc/dgnc_tty.c b/drivers/staging/dgnc/dgnc_tty.c
index ce4187f..96eaf5b 100644
--- a/drivers/staging/dgnc/dgnc_tty.c
+++ b/drivers/staging/dgnc/dgnc_tty.c
@@ -1682,10 +1682,15 @@ static int dgnc_tty_put_char(struct tty_struct *tty, 
unsigned char c)
        /*
         * Simply call tty_write.
         */
-       dgnc_tty_write(tty, &c, 1);
+       __dgnc_tty_write(tty, &c, 1, 0);
        return 1;
 }
 
+static int dgnc_tty_write(struct tty_struct *tty,
+               const unsigned char *buf, int count)
+{
+       __dgnc_tty_write(tty, buf, count, 1);
+}
 
 /*
  * dgnc_tty_write()
@@ -1693,8 +1698,8 @@ static int dgnc_tty_put_char(struct tty_struct *tty, 
unsigned char c)
  * Take data from the user or kernel and send it out to the FEP.
  * In here exists all the Transparent Print magic as well.
  */
-static int dgnc_tty_write(struct tty_struct *tty,
-               const unsigned char *buf, int count)
+static int __dgnc_tty_write(struct tty_struct *tty,
+               const unsigned char *buf, int count, int from_user)
 {
        struct channel_t *ch = NULL;
        struct un_t *un = NULL;
@@ -1705,7 +1710,6 @@ static int dgnc_tty_write(struct tty_struct *tty,
        ushort tail;
        ushort tmask;
        uint remain;
-       int from_user = 0;
 
        if (tty == NULL || dgnc_TmpWriteBuf == NULL)
                return 0;


regards
sudip
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