[PATCH 6/9] tty: Unify receive_buf() code paths

From: Peter Hurley
Date: Sun Jan 10 2016 - 17:46:00 EST


Instead of two distinct code branches for receive_buf() handling,
use tty_ldisc_receive_buf() as the single code path.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/tty_buffer.c | 39 ++++++++++++++++++++++++++++-----------
include/linux/tty.h | 16 ++--------------
2 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 3cd31e0..a946e49 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -435,25 +435,42 @@ int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars,
}
EXPORT_SYMBOL_GPL(tty_prepare_flip_string);

+/**
+ * tty_ldisc_receive_buf - forward data to line discipline
+ * @ld: line discipline to process input
+ * @p: char buffer
+ * @f: TTY_* flags buffer
+ * @count: number of bytes to process
+ *
+ * Callers other than flush_to_ldisc() need to exclude the kworker
+ * from concurrent use of the line discipline, see paste_selection().
+ *
+ * Returns the number of bytes not processed
+ */
+int tty_ldisc_receive_buf(struct tty_ldisc *ld, unsigned char *p,
+ char *f, int count)
+{
+ if (ld->ops->receive_buf2)
+ count = ld->ops->receive_buf2(ld->tty, p, f, count);
+ else {
+ count = min_t(int, count, ld->tty->receive_room);
+ if (count && ld->ops->receive_buf)
+ ld->ops->receive_buf(ld->tty, p, f, count);
+ }
+ return count;
+}
+EXPORT_SYMBOL_GPL(tty_ldisc_receive_buf);

static int
-receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
+receive_buf(struct tty_ldisc *ld, struct tty_buffer *head, int count)
{
- struct tty_ldisc *disc = tty->ldisc;
unsigned char *p = char_buf_ptr(head, head->read);
char *f = NULL;

if (~head->flags & TTYB_NORMAL)
f = flag_buf_ptr(head, head->read);

- if (disc->ops->receive_buf2)
- count = disc->ops->receive_buf2(tty, p, f, count);
- else {
- count = min_t(int, count, tty->receive_room);
- if (count && disc->ops->receive_buf)
- disc->ops->receive_buf(tty, p, f, count);
- }
- return count;
+ return tty_ldisc_receive_buf(ld, p, f, count);
}

/**
@@ -514,7 +531,7 @@ static void flush_to_ldisc(struct work_struct *work)
continue;
}

- count = receive_buf(tty, head, count);
+ count = receive_buf(disc, head, count);
if (!count)
break;
head->read += count;
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 03e4015..3b09f23 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -571,20 +571,8 @@ extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
extern void tty_ldisc_release(struct tty_struct *tty);
extern void tty_ldisc_init(struct tty_struct *tty);
extern void tty_ldisc_deinit(struct tty_struct *tty);
-
-static inline int tty_ldisc_receive_buf(struct tty_ldisc *ld, unsigned char *p,
- char *f, int count)
-{
- if (ld->ops->receive_buf2)
- count = ld->ops->receive_buf2(ld->tty, p, f, count);
- else {
- count = min_t(int, count, ld->tty->receive_room);
- if (count && ld->ops->receive_buf)
- ld->ops->receive_buf(ld->tty, p, f, count);
- }
- return count;
-}
-
+extern int tty_ldisc_receive_buf(struct tty_ldisc *ld, unsigned char *p,
+ char *f, int count);

/* n_tty.c */
extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
--
2.7.0