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Subject[PATCH 07/24] n_hdlc: simplify freeing of buffer list
Date
n_hdlc_release contains four loops to free each buffer list. Create a
helper (n_hdlc_free_buf_list) and call it for every list instead. It
makes n_hdlc_release more readable.

We are switching from "for (;;)" to "do {} while (buf)" which avoids the
"if (buf)" completely -- kfree is a nop for NULL pointers.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/tty/n_hdlc.c | 45 ++++++++++++++------------------------------
1 file changed, 14 insertions(+), 31 deletions(-)

diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index a713a98fea2e..07ba42badd7a 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -215,6 +215,16 @@ static struct tty_ldisc_ops n_hdlc_ldisc = {
.flush_buffer = flush_rx_queue,
};

+static void n_hdlc_free_buf_list(struct n_hdlc_buf_list *list)
+{
+ struct n_hdlc_buf *buf;
+
+ do {
+ buf = n_hdlc_buf_get(list);
+ kfree(buf);
+ } while (buf);
+}
+
/**
* n_hdlc_release - release an n_hdlc per device line discipline info structure
* @n_hdlc - per device line discipline info structure
@@ -222,7 +232,6 @@ static struct tty_ldisc_ops n_hdlc_ldisc = {
static void n_hdlc_release(struct n_hdlc *n_hdlc)
{
struct tty_struct *tty = n_hdlc2tty (n_hdlc);
- struct n_hdlc_buf *buf;

/* Ensure that the n_hdlcd process is not hanging on select()/poll() */
wake_up_interruptible (&tty->read_wait);
@@ -231,37 +240,11 @@ static void n_hdlc_release(struct n_hdlc *n_hdlc)
if (tty->disc_data == n_hdlc)
tty->disc_data = NULL; /* Break the tty->n_hdlc link */

- /* Release transmit and receive buffers */
- for(;;) {
- buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
- if (buf) {
- kfree(buf);
- } else
- break;
- }
- for(;;) {
- buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
- if (buf) {
- kfree(buf);
- } else
- break;
- }
- for(;;) {
- buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
- if (buf) {
- kfree(buf);
- } else
- break;
- }
- for(;;) {
- buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
- if (buf) {
- kfree(buf);
- } else
- break;
- }
+ n_hdlc_free_buf_list(&n_hdlc->rx_free_buf_list);
+ n_hdlc_free_buf_list(&n_hdlc->tx_free_buf_list);
+ n_hdlc_free_buf_list(&n_hdlc->rx_buf_list);
+ n_hdlc_free_buf_list(&n_hdlc->tx_buf_list);
kfree(n_hdlc);
-
} /* end of n_hdlc_release() */

/**
--
2.25.0
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