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Commit 5b21f9dd authored by Jiri Slaby's avatar Jiri Slaby Committed by Linus Torvalds
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Char: isicom, cleanup locking 



Don't spin processor when not needed (use sleep instead of delay).  Don't
release the lock when needed in next iteration -- this actually fixes a bug --
missing braces

Signed-off-by: default avatarJiri Slaby <jirislaby@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c4923b4f

drivers/char/isicom.c

+27 −38
Original line number Diff line number Diff line
@@ -243,17 +243,18 @@ static inline int WaitTillCardIsFree(u16 base) 


static int lock_card(struct isi_board *card)

{

	char		retries;

	unsigned long base = card->base;

	unsigned int retries, a;



	for (retries = 0; retries < 100; retries++) {

	for (retries = 0; retries < 10; retries++) {

		spin_lock_irqsave(&card->card_lock, card->flags);

		if (inw(base + 0xe) & 0x1) {

		for (a = 0; a < 10; a++) {

			if (inw(base + 0xe) & 0x1)

				return 1;

		} else {

			spin_unlock_irqrestore(&card->card_lock, card->flags);

			udelay(1000);   /* 1ms */

			udelay(10);

		}

		spin_unlock_irqrestore(&card->card_lock, card->flags);

		msleep(10);

	}

	printk(KERN_WARNING "ISICOM: Failed to lock Card (0x%lx)\n",

		card->base);
@@ -261,23 +262,6 @@ static int lock_card(struct isi_board *card) 
	return 0;	/* Failed to acquire the card! */

}



static int lock_card_at_interrupt(struct isi_board *card)

{

	unsigned char		retries;

	unsigned long base = card->base;



	for (retries = 0; retries < 200; retries++) {

		spin_lock_irqsave(&card->card_lock, card->flags);



		if (inw(base + 0xe) & 0x1)

			return 1;

		else

			spin_unlock_irqrestore(&card->card_lock, card->flags);

	}

	/* Failing in interrupt is an acceptable event */

	return 0;	/* Failed to acquire the card! */

}



static void unlock_card(struct isi_board *card)

{

	spin_unlock_irqrestore(&card->card_lock, card->flags);
@@ -415,6 +399,8 @@ static inline int __isicom_paranoia_check(struct isi_port const *port, 


static void isicom_tx(unsigned long _data)

{

	unsigned long flags;

	unsigned int retries;

	short count = (BOARD_COUNT-1), card, base;

	short txcount, wrd, residue, word_count, cnt;

	struct isi_port *port;
@@ -435,32 +421,34 @@ static void isicom_tx(unsigned long _data) 
	count = isi_card[card].port_count;

	port = isi_card[card].ports;

	base = isi_card[card].base;



	spin_lock_irqsave(&isi_card[card].card_lock, flags);

	for (retries = 0; retries < 100; retries++) {

		if (inw(base + 0xe) & 0x1)

			break;

		udelay(2);

	}

	if (retries >= 100)

		goto unlock;



	for (;count > 0;count--, port++) {

		if (!lock_card_at_interrupt(&isi_card[card]))

			continue;

		/* port not active or tx disabled to force flow control */

		if (!(port->flags & ASYNC_INITIALIZED) ||

				!(port->status & ISI_TXOK))

			unlock_card(&isi_card[card]);

			continue;



		tty = port->tty;





		if (tty == NULL) {

			unlock_card(&isi_card[card]);

		if (tty == NULL)

			continue;

		}



		txcount = min_t(short, TX_SIZE, port->xmit_cnt);

		if (txcount <= 0 || tty->stopped || tty->hw_stopped) {

			unlock_card(&isi_card[card]);

		if (txcount <= 0 || tty->stopped || tty->hw_stopped)

			continue;

		}

		if (!(inw(base + 0x02) & (1 << port->channel))) {

			unlock_card(&isi_card[card]);



		if (!(inw(base + 0x02) & (1 << port->channel)))

			continue;

		}



		pr_dbg("txing %d bytes, port%d.\n", txcount,

			port->channel + 1);

		outw((port->channel << isi_card[card].shift_count) | txcount,
@@ -508,9 +496,10 @@ static void isicom_tx(unsigned long _data) 
			port->status &= ~ISI_TXOK;

		if (port->xmit_cnt <= WAKEUP_CHARS)

			tty_wakeup(tty);

		unlock_card(&isi_card[card]);

	}



unlock:

	spin_unlock_irqrestore(&isi_card[card].card_lock, flags);

	/*	schedule another tx for hopefully in about 10ms	*/

sched_again:

	if (!re_schedule) {