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USB: mos7840: remove smp barriers from icount handling

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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 <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2013-03-21 12:37:15 +01:00 committed by Greg Kroah-Hartman
parent 3571157804
commit c9fac85345
1 changed files with 20 additions and 30 deletions
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50
drivers/usb/serial/mos7840.c
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@ -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);
cnow = mos7840_port->icount;
smp_rmb();
spin_lock_irqsave(&port->lock, flags);
cnow = mos7840_port->icount;
spin_unlock_irqrestore(&port->lock, flags);
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)) ||