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Subject[PATCH] Remove cli() from R3964 line discipline.
Date
I did this ages ago but never submitted it because I never got round to 
testing it. I still haven't tested it, but it ought to work, and the code
is definitely broken without it...

===== drivers/char/n_r3964.c 1.9 vs edited =====
--- 1.9/drivers/char/n_r3964.c Thu May 23 17:07:43 2002
+++ edited/drivers/char/n_r3964.c Mon Jul 29 11:39:36 2002
@@ -13,6 +13,12 @@
* L. Haag
*
* $Log: n_r3964.c,v $
+ * Revision 1.10 2001/03/18 13:02:24 dwmw2
+ * Fix timer usage, use spinlocks properly.
+ *
+ * Revision 1.9 2001/03/18 12:52:14 dwmw2
+ * Merge changes in 2.4.2
+ *
* Revision 1.8 2000/03/23 14:14:54 dwmw2
* Fix race in sleeping in r3964_read()
*
@@ -110,8 +116,6 @@
#define TRACE_Q(fmt, arg...) /**/
#endif

-static void on_timer_1(void*);
-static void on_timer_2(void*);
static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
static void put_char(struct r3964_info *pInfo, unsigned char ch);
@@ -120,7 +124,7 @@
static void transmit_block(struct r3964_info *pInfo);
static void receive_char(struct r3964_info *pInfo, const unsigned char c);
static void receive_error(struct r3964_info *pInfo, const char flag);
-static void on_timeout(struct r3964_info *pInfo);
+static void on_timeout(unsigned long priv);
static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg);
static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char *buf);
static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
@@ -217,7 +221,7 @@
{
int status;

- printk ("r3964: Philips r3964 Driver $Revision: 1.8 $\n");
+ printk ("r3964: Philips r3964 Driver $Revision: 1.10 $\n");

/*
* Register the tty line discipline
@@ -247,40 +251,11 @@
* Protocol implementation routines
*************************************************************/

-static void on_timer_1(void *arg)
-{
- struct r3964_info *pInfo = (struct r3964_info *)arg;
-
- if(pInfo->count_down)
- {
- if(!--pInfo->count_down)
- {
- on_timeout(pInfo);
- }
- }
- queue_task(&pInfo->bh_2, &tq_timer);
-}
-
-static void on_timer_2(void *arg)
-{
- struct r3964_info *pInfo = (struct r3964_info *)arg;
-
- if(pInfo->count_down)
- {
- if(!--pInfo->count_down)
- {
- on_timeout(pInfo);
- }
- }
- queue_task(&pInfo->bh_1, &tq_timer);
-}
-
static void add_tx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
{
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pInfo->lock, flags);

pHeader->next = NULL;

@@ -294,7 +269,7 @@
pInfo->tx_last = pHeader;
}

- restore_flags(flags);
+ spin_unlock_irqrestore(&pInfo->lock, flags);

TRACE_Q("add_tx_queue %x, length %d, tx_first = %x",
(int)pHeader, pHeader->length, (int)pInfo->tx_first );
@@ -337,8 +312,7 @@
wake_up_interruptible (&pInfo->read_wait);
}

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pInfo->lock, flags);

pInfo->tx_first = pHeader->next;
if(pInfo->tx_first==NULL)
@@ -346,7 +320,7 @@
pInfo->tx_last = NULL;
}

- restore_flags(flags);
+ spin_unlock_irqrestore(&pInfo->lock, flags);

kfree(pHeader);
TRACE_M("remove_from_tx_queue - kfree %x",(int)pHeader);
@@ -359,8 +333,7 @@
{
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pInfo->lock, flags);

pHeader->next = NULL;

@@ -375,7 +348,7 @@
}
pInfo->blocks_in_rx_queue++;

- restore_flags(flags);
+ spin_unlock_irqrestore(&pInfo->lock, flags);

TRACE_Q("add_rx_queue: %x, length = %d, rx_first = %x, count = %d",
(int)pHeader, pHeader->length,
@@ -396,8 +369,7 @@
TRACE_Q("remove_from_rx_queue: %x, length %d",
(int)pHeader, (int)pHeader->length );

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pInfo->lock, flags);

if(pInfo->rx_first == pHeader)
{
@@ -430,7 +402,7 @@
}
}

- restore_flags(flags);
+ spin_unlock_irqrestore(&pInfo->lock, flags);

kfree(pHeader);
TRACE_M("remove_from_rx_queue - kfree %x",(int)pHeader);
@@ -471,17 +443,16 @@
unsigned long flags;


- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pInfo->lock, flags);

if((pInfo->state == R3964_IDLE) && (pInfo->tx_first!=NULL))
{
pInfo->state = R3964_TX_REQUEST;
- pInfo->count_down = R3964_TO_QVZ;
pInfo->nRetry=0;
pInfo->flags &= ~R3964_ERROR;
-
- restore_flags(flags);
+ mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
+
+ spin_unlock_irqrestore(&pInfo->lock, flags);

TRACE_PS("trigger_transmit - sent STX");

@@ -492,7 +463,7 @@
}
else
{
- restore_flags(flags);
+ spin_unlock_irqrestore(&pInfo->lock, flags);
}
}

@@ -506,8 +477,8 @@
put_char(pInfo, STX);
flush(pInfo);
pInfo->state = R3964_TX_REQUEST;
- pInfo->count_down = R3964_TO_QVZ;
pInfo->nRetry++;
+ mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
}
else
{
@@ -566,7 +537,7 @@
put_char(pInfo, pInfo->bcc);
}
pInfo->state = R3964_WAIT_FOR_TX_ACK;
- pInfo->count_down = R3964_TO_QVZ;
+ mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
}
flush(pInfo);
}
@@ -601,8 +572,8 @@
if(pInfo->nRetry<R3964_MAX_RETRIES)
{
pInfo->state=R3964_WAIT_FOR_RX_REPEAT;
- pInfo->count_down = R3964_TO_RX_PANIC;
pInfo->nRetry++;
+ mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
}
else
{
@@ -616,7 +587,7 @@
/* received block; submit DLE: */
put_char(pInfo, DLE);
flush(pInfo);
- pInfo->count_down=0;
+ del_timer_sync(&pInfo->tmr);
TRACE_PS(" rx success: got %d chars", length);

/* prepare struct r3964_block_header: */
@@ -701,7 +672,7 @@
TRACE_PE("TRANSMITTING - got illegal char");

pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
- pInfo->count_down = R3964_TO_ZVZ;
+ mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
}
break;
case R3964_WAIT_FOR_TX_ACK:
@@ -728,7 +699,7 @@
{
TRACE_PE("IDLE - got STX but no space in rx_queue!");
pInfo->state=R3964_WAIT_FOR_RX_BUF;
- pInfo->count_down = R3964_TO_NO_BUF;
+ mod_timer(&pInfo->tmr, R3964_TO_NO_BUF);
break;
}
start_receiving:
@@ -738,8 +709,8 @@
pInfo->last_rx = 0;
pInfo->flags &= ~R3964_ERROR;
pInfo->state=R3964_RECEIVING;
- pInfo->count_down = R3964_TO_ZVZ;
- pInfo->nRetry = 0;
+ mod_timer(&pInfo->tmr, R3964_TO_ZVZ);
+ pInfo->nRetry = 0;
put_char(pInfo, DLE);
flush(pInfo);
pInfo->bcc = 0;
@@ -765,7 +736,7 @@
if(pInfo->flags & R3964_BCC)
{
pInfo->state = R3964_WAIT_FOR_BCC;
- pInfo->count_down = R3964_TO_ZVZ;
+ mod_timer(&pInfo->tmr, R3964_TO_ZVZ);
}
else
{
@@ -777,7 +748,7 @@
pInfo->last_rx = c;
char_to_buf:
pInfo->rx_buf[pInfo->rx_position++] = c;
- pInfo->count_down = R3964_TO_ZVZ;
+ mod_timer(&pInfo->tmr, R3964_TO_ZVZ);
}
}
/* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
@@ -818,8 +789,10 @@
}
}

-static void on_timeout(struct r3964_info *pInfo)
+static void on_timeout(unsigned long priv)
{
+ struct r3964_info *pInfo = (void *)priv;
+
switch(pInfo->state)
{
case R3964_TX_REQUEST:
@@ -926,6 +899,7 @@
return -ENOMEM;

TRACE_PS("add client %d to client list", pid);
+ spin_lock_init(&pClient->lock);
pClient->sig_flags=arg;
pClient->pid = pid;
pClient->next=pInfo->firstClient;
@@ -989,8 +963,7 @@
return;
}

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pClient->lock, flags);

pMsg->msg_id = msg_id;
pMsg->arg = arg;
@@ -1014,7 +987,7 @@
{
pBlock->locks++;
}
- restore_flags(flags);
+ spin_unlock_irqrestore(&pClient->lock, flags);
}
else
{
@@ -1049,8 +1022,7 @@

if(pClient->first_msg)
{
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pClient->lock, flags);

pMsg = pClient->first_msg;
pClient->first_msg = pMsg->next;
@@ -1065,7 +1037,7 @@
remove_client_block(pInfo, pClient);
pClient->next_block_to_read = pMsg->block;
}
- restore_flags(flags);
+ spin_unlock_irqrestore(&pClient->lock, flags);
}
return pMsg;
}
@@ -1137,6 +1109,7 @@
return -ENOMEM;
}

+ spin_lock_init(&pInfo->lock);
pInfo->tty = tty;
init_waitqueue_head (&pInfo->read_wait);
pInfo->priority = R3964_MASTER;
@@ -1149,26 +1122,13 @@
pInfo->firstClient=NULL;
pInfo->state=R3964_IDLE;
pInfo->flags = R3964_DEBUG;
- pInfo->count_down = 0;
pInfo->nRetry = 0;

tty->disc_data = pInfo;

- /*
- * Add 'on_timer' to timer task queue
- * (will be called from timer bh)
- */
- INIT_LIST_HEAD(&pInfo->bh_1.list);
- pInfo->bh_1.sync = 0;
- pInfo->bh_1.routine = &on_timer_1;
- pInfo->bh_1.data = pInfo;
-
- INIT_LIST_HEAD(&pInfo->bh_2.list);
- pInfo->bh_2.sync = 0;
- pInfo->bh_2.routine = &on_timer_2;
- pInfo->bh_2.data = pInfo;
-
- queue_task(&pInfo->bh_1, &tq_timer);
+ INIT_LIST_HEAD(&pInfo->tmr.list);
+ pInfo->tmr.data = (unsigned long)pInfo;
+ pInfo->tmr.function = on_timeout;

return 0;
}
@@ -1187,12 +1147,7 @@
* Make sure that our task queue isn't activated. If it
* is, take it out of the linked list.
*/
- spin_lock_irqsave(&tqueue_lock, flags);
- if (pInfo->bh_1.sync)
- list_del(&pInfo->bh_1.list);
- if (pInfo->bh_2.sync)
- list_del(&pInfo->bh_2.list);
- spin_unlock_irqrestore(&tqueue_lock, flags);
+ del_timer_sync(&pInfo->tmr);

/* Remove client-structs and message queues: */
pClient=pInfo->firstClient;
@@ -1213,11 +1168,10 @@
pClient=pNext;
}
/* Remove jobs from tx_queue: */
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pInfo->lock, flags);
pHeader=pInfo->tx_first;
pInfo->tx_first=pInfo->tx_last=NULL;
- restore_flags(flags);
+ spin_unlock_irqrestore(&pInfo->lock, flags);

while(pHeader)
{
@@ -1430,10 +1384,9 @@
if(pClient)
{
poll_wait(file, &pInfo->read_wait, wait);
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&pInfo->lock, flags);
pMsg=pClient->first_msg;
- restore_flags(flags);
+ spin_unlock_irqrestore(&pInfo->lock, flags);
if(pMsg)
result |= POLLIN | POLLRDNORM;
}
===== include/linux/n_r3964.h 1.2 vs edited =====
--- 1.2/include/linux/n_r3964.h Tue Feb 5 07:38:17 2002
+++ edited/include/linux/n_r3964.h Mon Jul 29 11:38:46 2002
@@ -13,6 +13,12 @@
* L. Haag
*
* $Log: r3964.h,v $
+ * Revision 1.3 2001/03/18 13:02:24 dwmw2
+ * Fix timer usage, use spinlocks properly.
+ *
+ * Revision 1.2 2001/03/18 12:53:15 dwmw2
+ * Merge changes in 2.4.2
+ *
* Revision 1.1.1.1 1998/10/13 16:43:14 dwmw2
* This'll screw the version control
*
@@ -103,8 +109,9 @@
struct r3964_message;

struct r3964_client_info {
+ spinlock_t lock;
pid_t pid;
- unsigned int sig_flags;
+ unsigned int sig_flags;

struct r3964_client_info *next;

@@ -186,6 +193,7 @@


struct r3964_info {
+ spinlock_t lock;
struct tty_struct *tty;
unsigned char priority;
unsigned char *rx_buf; /* ring buffer */
@@ -209,11 +217,8 @@
unsigned int state;
unsigned int flags;

- int count_down;
- int nRetry;
-
- struct tq_struct bh_1;
- struct tq_struct bh_2;
+ struct timer_list tmr;
+ int nRetry;
};

#endif
--
dwmw2


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