n_tty: Fix calculation of size in canon_copy_from_read_buf
There was a hardcoded value of 4096 which should have been N_TTY_BUF_SIZE.
This caused reads from tty to fail with EFAULT when they shouldn't have
done if N_TTY_BUF_SIZE was declared to be something other than 4096.
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index cc57a3a..759604e 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2070,8 +2070,8 @@
size = N_TTY_BUF_SIZE - tail;
n = eol - tail;
- if (n > 4096)
- n += 4096;
+ if (n > N_TTY_BUF_SIZE)
+ n += N_TTY_BUF_SIZE;
n += found;
c = n;