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n_hdlc: simplify freeing of buffer list 

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>
Link: https://lore.kernel.org/r/20200219084118.26491-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2020-02-19 09:41:01 +01:00 committed by Greg Kroah-Hartman
parent c549725ff8
commit 30fafd92c2
1 changed files with 14 additions and 31 deletions
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45
drivers/tty/n_hdlc.c
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@ -215,6 +215,16 @@ static struct tty_ldisc_ops n_hdlc_ldisc = {
.flush_buffer = flush_rx_queue, .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_release - release an n_hdlc per device line discipline info structure
* @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) static void n_hdlc_release(struct n_hdlc *n_hdlc)
{ {
struct tty_struct *tty = n_hdlc2tty (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() */ /* Ensure that the n_hdlcd process is not hanging on select()/poll() */
wake_up_interruptible (&tty->read_wait); 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) if (tty->disc_data == n_hdlc)
tty->disc_data = NULL; /* Break the tty->n_hdlc link */ tty->disc_data = NULL; /* Break the tty->n_hdlc link */
/* Release transmit and receive buffers */ n_hdlc_free_buf_list(&n_hdlc->rx_free_buf_list);
for(;;) { n_hdlc_free_buf_list(&n_hdlc->tx_free_buf_list);
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list); n_hdlc_free_buf_list(&n_hdlc->rx_buf_list);
if (buf) { n_hdlc_free_buf_list(&n_hdlc->tx_buf_list);
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;
}
kfree(n_hdlc); kfree(n_hdlc);
} /* end of n_hdlc_release() */ } /* end of n_hdlc_release() */
/** /**