From: Jiri Slaby Date: Sat, 30 Dec 2006 00:48:00 +0000 (-0800) Subject: [PATCH] Char: isicom, eliminate spinlock recursion X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=cfe7c09ac2be2a89aa46bb23d480d9d908e8c041;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git [PATCH] Char: isicom, eliminate spinlock recursion Many spinlock recursion was in the isicom driver. Eliminate it. Signed-off-by: Jiri Slaby Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c index 5a747e685993..01084abffddf 100644 --- a/drivers/char/isicom.c +++ b/drivers/char/isicom.c @@ -230,6 +230,20 @@ 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; @@ -276,69 +290,71 @@ 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; @@ -355,35 +371,20 @@ 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); } /* @@ -744,7 +745,7 @@ 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; @@ -772,7 +773,6 @@ 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; @@ -791,12 +791,11 @@ 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 */ @@ -821,10 +820,9 @@ 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) @@ -857,7 +855,12 @@ 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; @@ -983,28 +986,22 @@ 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; @@ -1012,7 +1009,6 @@ 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 @@ -1258,10 +1254,12 @@ 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) @@ -1271,6 +1269,7 @@ 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; } @@ -1303,7 +1302,10 @@ 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; } @@ -1384,6 +1386,7 @@ 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; @@ -1392,7 +1395,9 @@ 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)) { @@ -1469,11 +1474,15 @@ static void do_isicom_hangup(struct work_struct *work) 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; @@ -1578,16 +1587,6 @@ 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) {