Remove unused patch
This commit is contained in:
Jan Alexander Steffens
parent
cfc7c70688
commit
de9da39247
|
|
@ -1,311 +0,0 @@
|
|||
>From 1dea7a8061ad9212f4464464a80d0dcd477eceab Mon Sep 17 00:00:00 2001
|
||||
From: Alexander Popov <alex.popov () linux com>
|
||||
Date: Tue, 28 Feb 2017 19:28:54 +0300
|
||||
Subject: [PATCH 1/1] tty: n_hdlc: get rid of racy n_hdlc.tbuf
|
||||
|
||||
Currently N_HDLC line discipline uses a self-made singly linked list for
|
||||
data buffers and has n_hdlc.tbuf pointer for buffer retransmitting after
|
||||
an error.
|
||||
|
||||
The commit be10eb7589337e5defbe214dae038a53dd21add8
|
||||
("tty: n_hdlc add buffer flushing") introduced racy access to n_hdlc.tbuf.
|
||||
After tx error concurrent flush_tx_queue() and n_hdlc_send_frames() can put
|
||||
one data buffer to tx_free_buf_list twice. That causes double free in
|
||||
n_hdlc_release().
|
||||
|
||||
Let's use standard kernel linked list and get rid of n_hdlc.tbuf:
|
||||
in case of tx error put current data buffer after the head of tx_buf_list.
|
||||
|
||||
Signed-off-by: Alexander Popov <alex.popov () linux com>
|
||||
---
|
||||
drivers/tty/n_hdlc.c | 132 +++++++++++++++++++++++++++------------------------
|
||||
1 file changed, 69 insertions(+), 63 deletions(-)
|
||||
|
||||
diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
|
||||
index eb27883..728c824 100644
|
||||
--- a/drivers/tty/n_hdlc.c
|
||||
+++ b/drivers/tty/n_hdlc.c
|
||||
@@ -114,7 +114,7 @@
|
||||
#define DEFAULT_TX_BUF_COUNT 3
|
||||
|
||||
struct n_hdlc_buf {
|
||||
- struct n_hdlc_buf *link;
|
||||
+ struct list_head list_item;
|
||||
int count;
|
||||
char buf[1];
|
||||
};
|
||||
@@ -122,8 +122,7 @@ struct n_hdlc_buf {
|
||||
#define N_HDLC_BUF_SIZE (sizeof(struct n_hdlc_buf) + maxframe)
|
||||
|
||||
struct n_hdlc_buf_list {
|
||||
- struct n_hdlc_buf *head;
|
||||
- struct n_hdlc_buf *tail;
|
||||
+ struct list_head list;
|
||||
int count;
|
||||
spinlock_t spinlock;
|
||||
};
|
||||
@@ -136,7 +135,6 @@ struct n_hdlc_buf_list {
|
||||
* @backup_tty - TTY to use if tty gets closed
|
||||
* @tbusy - reentrancy flag for tx wakeup code
|
||||
* @woke_up - FIXME: describe this field
|
||||
- * @tbuf - currently transmitting tx buffer
|
||||
* @tx_buf_list - list of pending transmit frame buffers
|
||||
* @rx_buf_list - list of received frame buffers
|
||||
* @tx_free_buf_list - list unused transmit frame buffers
|
||||
@@ -149,7 +147,6 @@ struct n_hdlc {
|
||||
struct tty_struct *backup_tty;
|
||||
int tbusy;
|
||||
int woke_up;
|
||||
- struct n_hdlc_buf *tbuf;
|
||||
struct n_hdlc_buf_list tx_buf_list;
|
||||
struct n_hdlc_buf_list rx_buf_list;
|
||||
struct n_hdlc_buf_list tx_free_buf_list;
|
||||
@@ -159,6 +156,8 @@ struct n_hdlc {
|
||||
/*
|
||||
* HDLC buffer list manipulation functions
|
||||
*/
|
||||
+static void n_hdlc_buf_return(struct n_hdlc_buf_list *buf_list,
|
||||
+ struct n_hdlc_buf *buf);
|
||||
static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
|
||||
struct n_hdlc_buf *buf);
|
||||
static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *list);
|
||||
@@ -208,16 +207,9 @@ static void flush_tx_queue(struct tty_struct *tty)
|
||||
{
|
||||
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
|
||||
struct n_hdlc_buf *buf;
|
||||
- unsigned long flags;
|
||||
|
||||
while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list)))
|
||||
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf);
|
||||
- spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
|
||||
- if (n_hdlc->tbuf) {
|
||||
- n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf);
|
||||
- n_hdlc->tbuf = NULL;
|
||||
- }
|
||||
- spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
|
||||
}
|
||||
|
||||
static struct tty_ldisc_ops n_hdlc_ldisc = {
|
||||
@@ -283,7 +275,6 @@ static void n_hdlc_release(struct n_hdlc *n_hdlc)
|
||||
} else
|
||||
break;
|
||||
}
|
||||
- kfree(n_hdlc->tbuf);
|
||||
kfree(n_hdlc);
|
||||
|
||||
} /* end of n_hdlc_release() */
|
||||
@@ -402,13 +393,7 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
|
||||
n_hdlc->woke_up = 0;
|
||||
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
|
||||
|
||||
- /* get current transmit buffer or get new transmit */
|
||||
- /* buffer from list of pending transmit buffers */
|
||||
-
|
||||
- tbuf = n_hdlc->tbuf;
|
||||
- if (!tbuf)
|
||||
- tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
|
||||
-
|
||||
+ tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
|
||||
while (tbuf) {
|
||||
if (debuglevel >= DEBUG_LEVEL_INFO)
|
||||
printk("%s(%d)sending frame %p, count=%d\n",
|
||||
@@ -420,7 +405,7 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
|
||||
|
||||
/* rollback was possible and has been done */
|
||||
if (actual == -ERESTARTSYS) {
|
||||
- n_hdlc->tbuf = tbuf;
|
||||
+ n_hdlc_buf_return(&n_hdlc->tx_buf_list, tbuf);
|
||||
break;
|
||||
}
|
||||
/* if transmit error, throw frame away by */
|
||||
@@ -435,10 +420,7 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
|
||||
|
||||
/* free current transmit buffer */
|
||||
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf);
|
||||
-
|
||||
- /* this tx buffer is done */
|
||||
- n_hdlc->tbuf = NULL;
|
||||
-
|
||||
+
|
||||
/* wait up sleeping writers */
|
||||
wake_up_interruptible(&tty->write_wait);
|
||||
|
||||
@@ -448,10 +430,12 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
|
||||
if (debuglevel >= DEBUG_LEVEL_INFO)
|
||||
printk("%s(%d)frame %p pending\n",
|
||||
__FILE__,__LINE__,tbuf);
|
||||
-
|
||||
- /* buffer not accepted by driver */
|
||||
- /* set this buffer as pending buffer */
|
||||
- n_hdlc->tbuf = tbuf;
|
||||
+
|
||||
+ /*
|
||||
+ * the buffer was not accepted by driver,
|
||||
+ * return it back into tx queue
|
||||
+ */
|
||||
+ n_hdlc_buf_return(&n_hdlc->tx_buf_list, tbuf);
|
||||
break;
|
||||
}
|
||||
}
|
||||
@@ -749,7 +733,8 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
|
||||
int error = 0;
|
||||
int count;
|
||||
unsigned long flags;
|
||||
-
|
||||
+ struct n_hdlc_buf *buf = NULL;
|
||||
+
|
||||
if (debuglevel >= DEBUG_LEVEL_INFO)
|
||||
printk("%s(%d)n_hdlc_tty_ioctl() called %d\n",
|
||||
__FILE__,__LINE__,cmd);
|
||||
@@ -763,8 +748,10 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
|
||||
/* report count of read data available */
|
||||
/* in next available frame (if any) */
|
||||
spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags);
|
||||
- if (n_hdlc->rx_buf_list.head)
|
||||
- count = n_hdlc->rx_buf_list.head->count;
|
||||
+ buf = list_first_entry_or_null(&n_hdlc->rx_buf_list.list,
|
||||
+ struct n_hdlc_buf, list_item);
|
||||
+ if (buf)
|
||||
+ count = buf->count;
|
||||
else
|
||||
count = 0;
|
||||
spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags);
|
||||
@@ -776,8 +763,10 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
|
||||
count = tty_chars_in_buffer(tty);
|
||||
/* add size of next output frame in queue */
|
||||
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags);
|
||||
- if (n_hdlc->tx_buf_list.head)
|
||||
- count += n_hdlc->tx_buf_list.head->count;
|
||||
+ buf = list_first_entry_or_null(&n_hdlc->tx_buf_list.list,
|
||||
+ struct n_hdlc_buf, list_item);
|
||||
+ if (buf)
|
||||
+ count += buf->count;
|
||||
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags);
|
||||
error = put_user(count, (int __user *)arg);
|
||||
break;
|
||||
@@ -825,14 +814,14 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
|
||||
poll_wait(filp, &tty->write_wait, wait);
|
||||
|
||||
/* set bits for operations that won't block */
|
||||
- if (n_hdlc->rx_buf_list.head)
|
||||
+ if (!list_empty(&n_hdlc->rx_buf_list.list))
|
||||
mask |= POLLIN | POLLRDNORM; /* readable */
|
||||
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
|
||||
mask |= POLLHUP;
|
||||
if (tty_hung_up_p(filp))
|
||||
mask |= POLLHUP;
|
||||
if (!tty_is_writelocked(tty) &&
|
||||
- n_hdlc->tx_free_buf_list.head)
|
||||
+ !list_empty(&n_hdlc->tx_free_buf_list.list))
|
||||
mask |= POLLOUT | POLLWRNORM; /* writable */
|
||||
}
|
||||
return mask;
|
||||
@@ -856,7 +845,12 @@ static struct n_hdlc *n_hdlc_alloc(void)
|
||||
spin_lock_init(&n_hdlc->tx_free_buf_list.spinlock);
|
||||
spin_lock_init(&n_hdlc->rx_buf_list.spinlock);
|
||||
spin_lock_init(&n_hdlc->tx_buf_list.spinlock);
|
||||
-
|
||||
+
|
||||
+ INIT_LIST_HEAD(&n_hdlc->rx_free_buf_list.list);
|
||||
+ INIT_LIST_HEAD(&n_hdlc->tx_free_buf_list.list);
|
||||
+ INIT_LIST_HEAD(&n_hdlc->rx_buf_list.list);
|
||||
+ INIT_LIST_HEAD(&n_hdlc->tx_buf_list.list);
|
||||
+
|
||||
/* allocate free rx buffer list */
|
||||
for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) {
|
||||
buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL);
|
||||
@@ -884,53 +878,65 @@ static struct n_hdlc *n_hdlc_alloc(void)
|
||||
} /* end of n_hdlc_alloc() */
|
||||
|
||||
/**
|
||||
+ * n_hdlc_buf_return - put the HDLC buffer after the head of the specified list
|
||||
+ * @buf_list - pointer to the buffer list
|
||||
+ * @buf - pointer to the buffer
|
||||
+ */
|
||||
+static void n_hdlc_buf_return(struct n_hdlc_buf_list *buf_list,
|
||||
+ struct n_hdlc_buf *buf)
|
||||
+{
|
||||
+ unsigned long flags;
|
||||
+
|
||||
+ spin_lock_irqsave(&buf_list->spinlock, flags);
|
||||
+
|
||||
+ list_add(&buf->list_item, &buf_list->list);
|
||||
+ buf_list->count++;
|
||||
+
|
||||
+ spin_unlock_irqrestore(&buf_list->spinlock, flags);
|
||||
+}
|
||||
+
|
||||
+/**
|
||||
* n_hdlc_buf_put - add specified HDLC buffer to tail of specified list
|
||||
- * @list - pointer to buffer list
|
||||
+ * @buf_list - pointer to buffer list
|
||||
* @buf - pointer to buffer
|
||||
*/
|
||||
-static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
|
||||
+static void n_hdlc_buf_put(struct n_hdlc_buf_list *buf_list,
|
||||
struct n_hdlc_buf *buf)
|
||||
{
|
||||
unsigned long flags;
|
||||
- spin_lock_irqsave(&list->spinlock,flags);
|
||||
-
|
||||
- buf->link=NULL;
|
||||
- if (list->tail)
|
||||
- list->tail->link = buf;
|
||||
- else
|
||||
- list->head = buf;
|
||||
- list->tail = buf;
|
||||
- (list->count)++;
|
||||
-
|
||||
- spin_unlock_irqrestore(&list->spinlock,flags);
|
||||
-
|
||||
+
|
||||
+ spin_lock_irqsave(&buf_list->spinlock, flags);
|
||||
+
|
||||
+ list_add_tail(&buf->list_item, &buf_list->list);
|
||||
+ buf_list->count++;
|
||||
+
|
||||
+ spin_unlock_irqrestore(&buf_list->spinlock, flags);
|
||||
} /* end of n_hdlc_buf_put() */
|
||||
|
||||
/**
|
||||
* n_hdlc_buf_get - remove and return an HDLC buffer from list
|
||||
- * @list - pointer to HDLC buffer list
|
||||
+ * @buf_list - pointer to HDLC buffer list
|
||||
*
|
||||
* Remove and return an HDLC buffer from the head of the specified HDLC buffer
|
||||
* list.
|
||||
* Returns a pointer to HDLC buffer if available, otherwise %NULL.
|
||||
*/
|
||||
-static struct n_hdlc_buf* n_hdlc_buf_get(struct n_hdlc_buf_list *list)
|
||||
+static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *buf_list)
|
||||
{
|
||||
unsigned long flags;
|
||||
struct n_hdlc_buf *buf;
|
||||
- spin_lock_irqsave(&list->spinlock,flags);
|
||||
-
|
||||
- buf = list->head;
|
||||
+
|
||||
+ spin_lock_irqsave(&buf_list->spinlock, flags);
|
||||
+
|
||||
+ buf = list_first_entry_or_null(&buf_list->list,
|
||||
+ struct n_hdlc_buf, list_item);
|
||||
if (buf) {
|
||||
- list->head = buf->link;
|
||||
- (list->count)--;
|
||||
+ list_del(&buf->list_item);
|
||||
+ buf_list->count--;
|
||||
}
|
||||
- if (!list->head)
|
||||
- list->tail = NULL;
|
||||
-
|
||||
- spin_unlock_irqrestore(&list->spinlock,flags);
|
||||
+
|
||||
+ spin_unlock_irqrestore(&buf_list->spinlock, flags);
|
||||
return buf;
|
||||
-
|
||||
} /* end of n_hdlc_buf_get() */
|
||||
|
||||
static char hdlc_banner[] __initdata =
|
||||
--
|
||||
2.7.4
|
||||
|
||||
Loading…
Reference in New Issue