From c9fac85345ca8fd7f6519232a4c0024f648647b5 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 21 Mar 2013 12:37:15 +0100 Subject: [PATCH] USB: mos7840: remove smp barriers from icount handling Remove SMP memory barriers from icount handling and rely on the barriers implied by wait_event, sleep and locks, while using the port lock to guarantee atomicity. This is a step in moving over to the generic icount implementations. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/mos7840.c | 48 ++++++++++++++---------------------- 1 file changed, 19 insertions(+), 29 deletions(-) diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c index 979ef1999581..7af3d4206523 100644 --- a/drivers/usb/serial/mos7840.c +++ b/drivers/usb/serial/mos7840.c @@ -406,22 +406,14 @@ static void mos7840_handle_new_msr(struct moschip_port *port, __u8 new_msr) icount = &mos7840_port->icount; /* update input line counters */ - if (new_msr & MOS_MSR_DELTA_CTS) { + if (new_msr & MOS_MSR_DELTA_CTS) icount->cts++; - smp_wmb(); - } - if (new_msr & MOS_MSR_DELTA_DSR) { + if (new_msr & MOS_MSR_DELTA_DSR) icount->dsr++; - smp_wmb(); - } - if (new_msr & MOS_MSR_DELTA_CD) { + if (new_msr & MOS_MSR_DELTA_CD) icount->dcd++; - smp_wmb(); - } - if (new_msr & MOS_MSR_DELTA_RI) { + if (new_msr & MOS_MSR_DELTA_RI) icount->rng++; - smp_wmb(); - } mos7840_port->delta_msr_cond = 1; wake_up_interruptible(&port->port->delta_msr_wait); @@ -443,22 +435,14 @@ static void mos7840_handle_new_lsr(struct moschip_port *port, __u8 new_lsr) /* update input line counters */ icount = &port->icount; - if (new_lsr & SERIAL_LSR_BI) { + if (new_lsr & SERIAL_LSR_BI) icount->brk++; - smp_wmb(); - } - if (new_lsr & SERIAL_LSR_OE) { + if (new_lsr & SERIAL_LSR_OE) icount->overrun++; - smp_wmb(); - } - if (new_lsr & SERIAL_LSR_PE) { + if (new_lsr & SERIAL_LSR_PE) icount->parity++; - smp_wmb(); - } - if (new_lsr & SERIAL_LSR_FE) { + if (new_lsr & SERIAL_LSR_FE) icount->frame++; - smp_wmb(); - } } /************************************************************************/ @@ -778,7 +762,6 @@ static void mos7840_bulk_in_callback(struct urb *urb) tty_insert_flip_string(tport, data, urb->actual_length); tty_flip_buffer_push(tport); mos7840_port->icount.rx += urb->actual_length; - smp_wmb(); dev_dbg(&port->dev, "mos7840_port->icount.rx is %d:\n", mos7840_port->icount.rx); } @@ -1507,7 +1490,6 @@ static int mos7840_write(struct tty_struct *tty, struct usb_serial_port *port, } bytes_sent = transfer_size; mos7840_port->icount.tx += transfer_size; - smp_wmb(); dev_dbg(&port->dev, "mos7840_port->icount.tx is %d:\n", mos7840_port->icount.tx); exit: return bytes_sent; @@ -2133,11 +2115,14 @@ static int mos7840_get_icount(struct tty_struct *tty, struct usb_serial_port *port = tty->driver_data; struct moschip_port *mos7840_port; struct async_icount cnow; + unsigned long flags; mos7840_port = mos7840_get_port_private(port); + + spin_lock_irqsave(&port->lock, flags); cnow = mos7840_port->icount; + spin_unlock_irqrestore(&port->lock, flags); - smp_rmb(); icount->cts = cnow.cts; icount->dsr = cnow.dsr; icount->rng = cnow.rng; @@ -2166,7 +2151,7 @@ static int mos7840_ioctl(struct tty_struct *tty, struct usb_serial_port *port = tty->driver_data; void __user *argp = (void __user *)arg; struct moschip_port *mos7840_port; - + unsigned long flags; struct async_icount cnow; struct async_icount cprev; @@ -2197,7 +2182,9 @@ static int mos7840_ioctl(struct tty_struct *tty, case TIOCMIWAIT: dev_dbg(&port->dev, "%s TIOCMIWAIT\n", __func__); + spin_lock_irqsave(&port->lock, flags); cprev = mos7840_port->icount; + spin_unlock_irqrestore(&port->lock, flags); while (1) { /* interruptible_sleep_on(&mos7840_port->delta_msr_wait); */ mos7840_port->delta_msr_cond = 0; @@ -2213,11 +2200,14 @@ static int mos7840_ioctl(struct tty_struct *tty, if (port->serial->disconnected) return -EIO; + spin_lock_irqsave(&port->lock, flags); cnow = mos7840_port->icount; - smp_rmb(); + spin_unlock_irqrestore(&port->lock, flags); + if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr && cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) return -EIO; /* no change => error */ + if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) || ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) || ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) || -- 2.20.1