From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753720AbWLWTq3 (ORCPT ); Sat, 23 Dec 2006 14:46:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753724AbWLWTq3 (ORCPT ); Sat, 23 Dec 2006 14:46:29 -0500 Received: from cacti.profiwh.com ([85.93.165.66]:40904 "EHLO cacti.profiwh.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753715AbWLWTq2 (ORCPT ); Sat, 23 Dec 2006 14:46:28 -0500 Message-id: <2249412545243025582@wsc.cz> Subject: [PATCH 1/1] Char: isicom, eliminate spinlock recursion From: Jiri Slaby To: Andrew Morton Cc: Date: Sat, 23 Dec 2006 20:46:35 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org isicom, eliminate spinlock recursion Many spinlock recursion was in the isicom driver. Eliminate it. Signed-off-by: Jiri Slaby --- commit 59988b8c2d1ce45e5ccb715ac7ece78dfb73545a tree d6060769defd71c77ffa340d579f95e24b783ebf parent fe13ee556f3b973a3b27f154db9852766634d0d6 author Jiri Slaby Sat, 23 Dec 2006 20:43:42 +0059 committer Jiri Slaby Sat, 23 Dec 2006 20:43:42 +0059 drivers/char/isicom.c | 103 ++++++++++++++++++++++++------------------------- 1 files changed, 51 insertions(+), 52 deletions(-) diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c index 0362740..26d3f78 100644 --- a/drivers/char/isicom.c +++ b/drivers/char/isicom.c @@ -228,6 +228,20 @@ static struct isi_port isi_ports[PORT_COUNT]; * it wants to talk. */ +static inline int WaitTillCardIsFree(u16 base) +{ + unsigned int count = 0; + unsigned int a = in_atomic(); /* do we run under spinlock? */ + + while (!(inw(base + 0xe) & 0x1) && count++ < 100) + if (a) + mdelay(1); + else + msleep(1); + + return !(inw(base + 0xe) & 0x1); +} + static int lock_card(struct isi_board *card) { char retries; @@ -274,69 +288,71 @@ static void unlock_card(struct isi_board *card) * ISI Card specific ops ... */ +/* card->lock HAS to be held */ static void raise_dtr(struct isi_port *port) { struct isi_board *card = port->card; unsigned long base = card->base; u16 channel = port->channel; - if (!lock_card(card)) + if (WaitTillCardIsFree(base)) return; outw(0x8000 | (channel << card->shift_count) | 0x02, base); outw(0x0504, base); InterruptTheCard(base); port->status |= ISI_DTR; - unlock_card(card); } +/* card->lock HAS to be held */ static inline void drop_dtr(struct isi_port *port) { struct isi_board *card = port->card; unsigned long base = card->base; u16 channel = port->channel; - if (!lock_card(card)) + if (WaitTillCardIsFree(base)) return; outw(0x8000 | (channel << card->shift_count) | 0x02, base); outw(0x0404, base); InterruptTheCard(base); port->status &= ~ISI_DTR; - unlock_card(card); } +/* card->lock HAS to be held */ static inline void raise_rts(struct isi_port *port) { struct isi_board *card = port->card; unsigned long base = card->base; u16 channel = port->channel; - if (!lock_card(card)) + if (WaitTillCardIsFree(base)) return; outw(0x8000 | (channel << card->shift_count) | 0x02, base); outw(0x0a04, base); InterruptTheCard(base); port->status |= ISI_RTS; - unlock_card(card); } + +/* card->lock HAS to be held */ static inline void drop_rts(struct isi_port *port) { struct isi_board *card = port->card; unsigned long base = card->base; u16 channel = port->channel; - if (!lock_card(card)) + if (WaitTillCardIsFree(base)) return; outw(0x8000 | (channel << card->shift_count) | 0x02, base); outw(0x0804, base); InterruptTheCard(base); port->status &= ~ISI_RTS; - unlock_card(card); } +/* card->lock MUST NOT be held */ static inline void raise_dtr_rts(struct isi_port *port) { struct isi_board *card = port->card; @@ -353,35 +369,20 @@ static inline void raise_dtr_rts(struct isi_port *port) unlock_card(card); } +/* card->lock HAS to be held */ static void drop_dtr_rts(struct isi_port *port) { struct isi_board *card = port->card; unsigned long base = card->base; u16 channel = port->channel; - if (!lock_card(card)) + if (WaitTillCardIsFree(base)) return; outw(0x8000 | (channel << card->shift_count) | 0x02, base); outw(0x0c04, base); InterruptTheCard(base); port->status &= ~(ISI_RTS | ISI_DTR); - unlock_card(card); -} - -static inline void kill_queue(struct isi_port *port, short queue) -{ - struct isi_board *card = port->card; - unsigned long base = card->base; - u16 channel = port->channel; - - if (!lock_card(card)) - return; - - outw(0x8000 | (channel << card->shift_count) | 0x02, base); - outw((queue << 8) | 0x06, base); - InterruptTheCard(base); - unlock_card(card); } /* @@ -727,7 +728,7 @@ static void isicom_config_port(struct isi_port *port) else raise_dtr(port); - if (lock_card(card)) { + if (WaitTillCardIsFree(base) == 0) { outw(0x8000 | (channel << shift_count) |0x03, base); outw(linuxb_to_isib[baud] << 8 | 0x03, base); channel_setup = 0; @@ -755,7 +756,6 @@ static void isicom_config_port(struct isi_port *port) } outw(channel_setup, base); InterruptTheCard(base); - unlock_card(card); } if (C_CLOCAL(tty)) port->flags &= ~ASYNC_CHECK_CD; @@ -774,12 +774,11 @@ static void isicom_config_port(struct isi_port *port) if (I_IXOFF(tty)) flow_ctrl |= ISICOM_INITIATE_XONXOFF; - if (lock_card(card)) { + if (WaitTillCardIsFree(base) == 0) { outw(0x8000 | (channel << shift_count) |0x04, base); outw(flow_ctrl << 8 | 0x05, base); outw((STOP_CHAR(tty)) << 8 | (START_CHAR(tty)), base); InterruptTheCard(base); - unlock_card(card); } /* rx enabled -> enable port for rx on the card */ @@ -804,10 +803,9 @@ static inline void isicom_setup_board(struct isi_board *bp) } port = bp->ports; bp->status |= BOARD_ACTIVE; - spin_unlock_irqrestore(&bp->card_lock, flags); for (channel = 0; channel < bp->port_count; channel++, port++) drop_dtr_rts(port); - return; + spin_unlock_irqrestore(&bp->card_lock, flags); } static int isicom_setup_port(struct isi_port *port) @@ -840,7 +838,12 @@ static int isicom_setup_port(struct isi_port *port) port->xmit_cnt = port->xmit_head = port->xmit_tail = 0; /* discard any residual data */ - kill_queue(port, ISICOM_KILLTX | ISICOM_KILLRX); + if (WaitTillCardIsFree(card->base) == 0) { + outw(0x8000 | (port->channel << card->shift_count) | 0x02, + card->base); + outw(((ISICOM_KILLTX | ISICOM_KILLRX) << 8) | 0x06, card->base); + InterruptTheCard(card->base); + } isicom_config_port(port); port->flags |= ASYNC_INITIALIZED; @@ -966,28 +969,22 @@ static int isicom_open(struct tty_struct *tty, struct file *filp) static inline void isicom_shutdown_board(struct isi_board *bp) { - unsigned long flags; - - spin_lock_irqsave(&bp->card_lock, flags); if (bp->status & BOARD_ACTIVE) { bp->status &= ~BOARD_ACTIVE; } - spin_unlock_irqrestore(&bp->card_lock, flags); } +/* card->lock HAS to be held */ static void isicom_shutdown_port(struct isi_port *port) { struct isi_board *card = port->card; struct tty_struct *tty; - unsigned long flags; tty = port->tty; - spin_lock_irqsave(&card->card_lock, flags); - if (!(port->flags & ASYNC_INITIALIZED)) { - spin_unlock_irqrestore(&card->card_lock, flags); + if (!(port->flags & ASYNC_INITIALIZED)) return; - } + if (port->xmit_buf) { free_page((unsigned long) port->xmit_buf); port->xmit_buf = NULL; @@ -995,7 +992,6 @@ static void isicom_shutdown_port(struct isi_port *port) port->flags &= ~ASYNC_INITIALIZED; /* 3rd October 2000 : Vinayak P Risbud */ port->tty = NULL; - spin_unlock_irqrestore(&card->card_lock, flags); /*Fix done by Anil .S on 30-04-2001 remote login through isi port has dtr toggle problem @@ -1241,10 +1237,12 @@ static int isicom_tiocmset(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear) { struct isi_port *port = tty->driver_data; + unsigned long flags; if (isicom_paranoia_check(port, tty->name, "isicom_ioctl")) return -ENODEV; + spin_lock_irqsave(&port->card->card_lock, flags); if (set & TIOCM_RTS) raise_rts(port); if (set & TIOCM_DTR) @@ -1254,6 +1252,7 @@ static int isicom_tiocmset(struct tty_struct *tty, struct file *file, drop_rts(port); if (clear & TIOCM_DTR) drop_dtr(port); + spin_unlock_irqrestore(&port->card->card_lock, flags); return 0; } @@ -1286,7 +1285,10 @@ static int isicom_set_serial_info(struct isi_port *port, (newinfo.flags & ASYNC_FLAGS)); } if (reconfig_port) { + unsigned long flags; + spin_lock_irqsave(&port->card->card_lock, flags); isicom_config_port(port); + spin_unlock_irqrestore(&port->card->card_lock, flags); } return 0; } @@ -1367,6 +1369,7 @@ static void isicom_set_termios(struct tty_struct *tty, struct ktermios *old_termios) { struct isi_port *port = tty->driver_data; + unsigned long flags; if (isicom_paranoia_check(port, tty->name, "isicom_set_termios")) return; @@ -1375,7 +1378,9 @@ static void isicom_set_termios(struct tty_struct *tty, tty->termios->c_iflag == old_termios->c_iflag) return; + spin_lock_irqsave(&port->card->card_lock, flags); isicom_config_port(port); + spin_unlock_irqrestore(&port->card->card_lock, flags); if ((old_termios->c_cflag & CRTSCTS) && !(tty->termios->c_cflag & CRTSCTS)) { @@ -1441,11 +1446,15 @@ static void isicom_start(struct tty_struct *tty) static void isicom_hangup(struct tty_struct *tty) { struct isi_port *port = tty->driver_data; + unsigned long flags; if (isicom_paranoia_check(port, tty->name, "isicom_hangup")) return; + spin_lock_irqsave(&port->card->card_lock, flags); isicom_shutdown_port(port); + spin_unlock_irqrestore(&port->card->card_lock, flags); + port->count = 0; port->flags &= ~ASYNC_NORMAL_ACTIVE; port->tty = NULL; @@ -1550,16 +1559,6 @@ end: return retval; } -static inline int WaitTillCardIsFree(u16 base) -{ - unsigned long count = 0; - - while (!(inw(base + 0xe) & 0x1) && count++ < 100) - msleep(5); - - return !(inw(base + 0xe) & 0x1); -} - static int __devinit load_firmware(struct pci_dev *pdev, const unsigned int index, const unsigned int signature) {