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    SubjectRe: [PATCH] use mutex instead of semaphore in RocketPort driver v2
    Matthias Kaehlcke napsal(a):
    > the RocketPort driver uses a semaphore as mutex. use the mutex API
    > instead of the (binary) semaphore
    >
    > Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
    >
    > --
    >
    > diff --git a/drivers/char/rocket.c b/drivers/char/rocket.c
    > index 76357c8..7d23790 100644
    > --- a/drivers/char/rocket.c
    > +++ b/drivers/char/rocket.c
    > @@ -702,7 +702,7 @@ static void init_r_port(int board, int aiop, int chan, struct pci_dev *pci_dev)
    > }
    > }
    > spin_lock_init(&info->slock);
    > - sema_init(&info->write_sem, 1);
    > + mutex_init(&info->write_mtx);
    > rp_table[line] = info;
    > if (pci_dev)
    > tty_register_device(rocket_driver, line, &pci_dev->dev);
    > @@ -1662,7 +1662,7 @@ static void rp_put_char(struct tty_struct *tty, unsigned char ch)
    > return;
    >
    > /* Grab the port write semaphore, locking out other processes that try to write to this port */
    > - down(&info->write_sem);
    > + mutex_lock(&info->write_mtx);
    >
    > #ifdef ROCKET_DEBUG_WRITE
    > printk(KERN_INFO "rp_put_char %c...", ch);
    > @@ -1684,7 +1684,7 @@ static void rp_put_char(struct tty_struct *tty, unsigned char ch)
    > info->xmit_fifo_room--;
    > }
    > spin_unlock_irqrestore(&info->slock, flags);
    > - up(&info->write_sem);
    > + mutex_unlock(&info->write_mtx);
    > }
    >
    > /*
    > @@ -1706,7 +1706,8 @@ static int rp_write(struct tty_struct *tty,
    > if (count <= 0 || rocket_paranoia_check(info, "rp_write"))
    > return 0;
    >
    > - down_interruptible(&info->write_sem);
    > + if(mutex_lock_interruptible(&info->write_mtx))
    > + return -EINTR;

    I think that ERESTARTSYS is appropriate here.

    reagrds,
    --
    http://www.fi.muni.cz/~xslaby/ Jiri Slaby
    faculty of informatics, masaryk university, brno, cz
    e-mail: jirislaby gmail com, gpg pubkey fingerprint:
    B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
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