Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261219AbVAHREx (ORCPT ); Sat, 8 Jan 2005 12:04:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261230AbVAHREx (ORCPT ); Sat, 8 Jan 2005 12:04:53 -0500 Received: from out005pub.verizon.net ([206.46.170.143]:44281 "EHLO out005.verizon.net") by vger.kernel.org with ESMTP id S261219AbVAHRD7 (ORCPT ); Sat, 8 Jan 2005 12:03:59 -0500 From: James Nelson To: linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org Cc: paulus@samba.org, James Nelson Message-Id: <20050108170415.32690.36069.48247@localhost.localdomain> In-Reply-To: <20050108170406.32690.36989.11853@localhost.localdomain> References: <20050108170406.32690.36989.11853@localhost.localdomain> Subject: [RESEND] [PATCH 1/7] ppc: remove cli()/sti() in arch/ppc/4xx_io/serial_sicc.c X-Authentication-Info: Submitted using SMTP AUTH at out005.verizon.net from [209.158.220.243] at Sat, 8 Jan 2005 11:03:55 -0600 Date: Sat, 8 Jan 2005 11:03:58 -0600 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11962 Lines: 370 Replace save_flags()/restore_flags() with spin_lock_irqsave()/spin_unlock_irqrestore() and document reasons for using spinlocks. Signed-off-by: James Nelson diff -urN --exclude='*~' linux-2.6.10-mm1-original/arch/ppc/4xx_io/serial_sicc.c linux-2.6.10-mm1/arch/ppc/4xx_io/serial_sicc.c --- linux-2.6.10-mm1-original/arch/ppc/4xx_io/serial_sicc.c 2004-12-24 16:33:49.000000000 -0500 +++ linux-2.6.10-mm1/arch/ppc/4xx_io/serial_sicc.c 2005-01-07 19:12:42.043984196 -0500 @@ -264,6 +264,7 @@ unsigned int flags; int count; struct SICC_info *info; + spinlock_t sicc_lock; }; #define SICC_XMIT_SIZE 1024 @@ -385,9 +386,10 @@ struct SICC_info *info = tty->driver_data; unsigned long flags; - save_flags(flags); cli(); + /* disable interrupts while stopping serial port interrupts */ + spin_lock_irqsave(&info->state->sicc_lock,flags); siccuart_disable_tx_interrupt(info); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } static void siccuart_start(struct tty_struct *tty) @@ -395,11 +397,12 @@ struct SICC_info *info = tty->driver_data; unsigned long flags; - save_flags(flags); cli(); + /* disable interrupts while starting serial port interrupts */ + spin_lock_irqsave(&info->state->sicc_lock,flags); if (info->xmit.head != info->xmit.tail && info->xmit.buf) siccuart_enable_tx_interrupt(info); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } @@ -604,7 +607,8 @@ return -ENOMEM; } - save_flags(flags); cli(); + /* lock access to info while doing setup */ + spin_lock_irqsave(&info->state->sicc_lock,flags); if (info->xmit.buf) free_page(page); @@ -688,12 +692,12 @@ siccuart_enable_rx_interrupt(info); info->flags |= ASYNC_INITIALIZED; - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); return 0; errout: - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); return retval; } @@ -708,7 +712,8 @@ if (!(info->flags & ASYNC_INITIALIZED)) return; - save_flags(flags); cli(); /* Disable interrupts */ + /* lock while shutting down port */ + spin_lock_irqsave(&info->state->sicc_lock,flags); /* Disable interrupts */ /* * clear delta_msr_wait queue to avoid mem leaks: we may free the irq @@ -746,7 +751,7 @@ info->flags &= ~ASYNC_INITIALIZED; - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } @@ -868,8 +873,8 @@ info->ignore_status_mask |= _LSR_OE_MASK; } - /* first, disable everything */ - save_flags(flags); cli(); + /* disable interrupts while reading and clearing registers */ + spin_lock_irqsave(&info->state->sicc_lock,flags); old_rcr = readb(info->port->uart_base + BL_SICC_RCR); old_tcr = readb(info->port->uart_base + BL_SICC_TxCR); @@ -881,7 +886,7 @@ /*RLBtrace (&ppc403Chan0, 0x2000000c, 0, 0);*/ - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); /* Set baud rate */ @@ -909,12 +914,13 @@ if (!tty || !info->xmit.buf) return; - save_flags(flags); cli(); + /* lock info->xmit while adding character to tx buffer */ + spin_lock_irqsave(&info->state->sicc_lock,flags); if (CIRC_SPACE(info->xmit.head, info->xmit.tail, SICC_XMIT_SIZE) != 0) { info->xmit.buf[info->xmit.head] = ch; info->xmit.head = (info->xmit.head + 1) & (SICC_XMIT_SIZE - 1); } - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } static void siccuart_flush_chars(struct tty_struct *tty) @@ -928,9 +934,10 @@ || !info->xmit.buf) return; - save_flags(flags); cli(); + /* disable interrupts while transmitting characters */ + spin_lock_irqsave(&info->state->sicc_lock,flags); siccuart_enable_tx_interrupt(info); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } static int siccuart_write(struct tty_struct *tty, @@ -943,8 +950,8 @@ if (!tty || !info->xmit.buf || !tmp_buf) return 0; - save_flags(flags); - cli(); + /* lock info->xmit while removing characters from buffer */ + spin_lock_irqsave(&info->state->sicc_lock,flags); while (1) { c = CIRC_SPACE_TO_END(info->xmit.head, info->xmit.tail, @@ -960,11 +967,11 @@ count -= c; ret += c; } - restore_flags(flags); if (info->xmit.head != info->xmit.tail && !tty->stopped && !tty->hw_stopped) siccuart_enable_tx_interrupt(info); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); return ret; } @@ -988,9 +995,10 @@ unsigned long flags; pr_debug("siccuart_flush_buffer(%d) called\n", tty->index); - save_flags(flags); cli(); + /* lock info->xmit while zeroing buffer counts */ + spin_lock_irqsave(&info->state->sicc_lock,flags); info->xmit.head = info->xmit.tail = 0; - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); wake_up_interruptible(&tty->write_wait); if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && tty->ldisc.write_wakeup) @@ -1019,10 +1027,11 @@ siccuart_send_xchar(tty, STOP_CHAR(tty)); if (tty->termios->c_cflag & CRTSCTS) { - save_flags(flags); cli(); + /* disable interrupts while setting modem control lines */ + spin_lock_irqsave(&info->state->sicc_lock,flags); info->mctrl &= ~TIOCM_RTS; info->port->set_mctrl(info->port, info->mctrl); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } } @@ -1039,10 +1048,11 @@ } if (tty->termios->c_cflag & CRTSCTS) { - save_flags(flags); cli(); + /* disable interrupts while setting modem control lines */ + spin_lock_irqsave(&info->state->sicc_lock,flags); info->mctrl |= TIOCM_RTS; info->port->set_mctrl(info->port, info->mctrl); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } } @@ -1181,9 +1191,10 @@ unsigned int result, status; unsigned long flags; - save_flags(flags); cli(); + /* disable interrupts while reading status from port */ + spin_lock_irqsave(&info->state->sicc_lock,flags); status = readb(info->port->uart_base + BL_SICC_LSR); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); result = status & _LSR_TSR_EMPTY ? TIOCSER_TEMT : 0; /* @@ -1234,10 +1245,11 @@ default: return -EINVAL; } - save_flags(flags); cli(); + /* disable interrupts while setting modem control lines */ + spin_lock_irqsave(&info->state->sicc_lock,flags); if (old != info->mctrl) info->port->set_mctrl(info->port, info->mctrl); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); return 0; } @@ -1248,14 +1260,15 @@ unsigned int lcr_h; - save_flags(flags); cli(); + /* disable interrupts while setting break state */ + spin_lock_irqsave(&info->state->sicc_lock,flags); lcr_h = readb(info->port + BL_SICC_LSR); if (break_state == -1) lcr_h |= _LSR_LB_MASK; else lcr_h &= ~_LSR_LB_MASK; writeb(lcr_h, info->port + BL_SICC_LSRS); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } static int siccuart_ioctl(struct tty_struct *tty, struct file *file, @@ -1303,9 +1316,10 @@ * RI where only 0->1 is counted. */ case TIOCGICOUNT: - save_flags(flags); cli(); + /* disable interrupts while getting interrupt count */ + spin_lock_irqsave(&info->state->sicc_lock,flags); cnow = info->state->icount; - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); icount.cts = cnow.cts; icount.dsr = cnow.dsr; icount.rng = cnow.rng; @@ -1342,22 +1356,24 @@ /* Handle transition to B0 status */ if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) { - save_flags(flags); cli(); + /* disable interrupts while setting break state */ + spin_lock_irqsave(&info->state->sicc_lock,flags); info->mctrl &= ~(TIOCM_RTS | TIOCM_DTR); info->port->set_mctrl(info->port, info->mctrl); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } /* Handle transition away from B0 status */ if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) { - save_flags(flags); cli(); + /* disable interrupts while setting break state */ + spin_lock_irqsave(&info->state->sicc_lock,flags); info->mctrl |= TIOCM_DTR; if (!(cflag & CRTSCTS) || !test_bit(TTY_THROTTLED, &tty->flags)) info->mctrl |= TIOCM_RTS; info->port->set_mctrl(info->port, info->mctrl); - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); } /* Handle turning off CRTSCTS */ @@ -1393,11 +1409,11 @@ //pr_debug("siccuart_close() called\n"); - save_flags(flags); cli(); + /* lock tty->driver_data while closing port */ + spin_lock_irqsave(&info->state->sicc_lock,flags); if (tty_hung_up_p(filp)) { - restore_flags(flags); - return; + goto quick_close; } if ((tty->count == 1) && (state->count != 1)) { @@ -1416,11 +1432,10 @@ state->count = 0; } if (state->count) { - restore_flags(flags); - return; + goto quick_close; } info->flags |= ASYNC_CLOSING; - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); /* * Now we wait for the transmit buffer to clear; and we notify * the line discipline to only process XON/XOFF characters. @@ -1458,6 +1473,11 @@ } info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING); wake_up_interruptible(&info->close_wait); + return; + +quick_close: + spin_unlock_irqrestore(&info->state->sicc_lock,flags); + return; } static void siccuart_wait_until_sent(struct tty_struct *tty, int timeout) @@ -1569,20 +1589,22 @@ */ retval = 0; add_wait_queue(&info->open_wait, &wait); - save_flags(flags); cli(); + /* lock while decrementing state->count */ + spin_lock_irqsave(&info->state->sicc_lock,flags); if (!tty_hung_up_p(filp)) { extra_count = 1; state->count--; } - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); info->blocked_open++; while (1) { - save_flags(flags); cli(); + /* disable interrupts while setting modem control lines */ + spin_lock_irqsave(&info->state->sicc_lock,flags); if (tty->termios->c_cflag & CBAUD) { info->mctrl = TIOCM_DTR | TIOCM_RTS; info->port->set_mctrl(info->port, info->mctrl); } - restore_flags(flags); + spin_unlock_irqrestore(&info->state->sicc_lock,flags); set_current_state(TASK_INTERRUPTIBLE); if (tty_hung_up_p(filp) || !(info->flags & ASYNC_INITIALIZED)) { @@ -1753,6 +1775,7 @@ state->line = i; state->close_delay = 5 * HZ / 10; state->closing_wait = 30 * HZ; + spin_lock_init(&state->sicc_lock); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/