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Date: Sat, 9 Jan 2016 21:13:44 -0800 From: Peter Hurley <peter@...leysoftware.com> To: Greg Kroah-Hartman <gregkh@...uxfoundation.org> Cc: Jiri Slaby <jslaby@...e.cz>, linux-kernel@...r.kernel.org, Peter Hurley <peter@...leysoftware.com> Subject: [PATCH v2 01/10] tty: Wait interruptibly for tty lock on reopen Allow a signal to interrupt the wait for a tty reopen; eg., if the tty has starting final close and is waiting for the device to drain. Signed-off-by: Peter Hurley <peter@...leysoftware.com> --- drivers/tty/tty_io.c | 8 +++++++- drivers/tty/tty_mutex.c | 8 ++++++++ include/linux/tty.h | 1 + 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index eda8715..1bf67a2 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2071,7 +2071,12 @@ retry_open: if (tty) { mutex_unlock(&tty_mutex); - tty_lock(tty); + retval = tty_lock_interruptible(tty); + if (retval) { + if (retval == -EINTR) + retval = -ERESTARTSYS; + goto err_unref; + } /* safe to drop the kref from tty_driver_lookup_tty() */ tty_kref_put(tty); retval = tty_reopen(tty); @@ -2158,6 +2163,7 @@ retry_open: return 0; err_unlock: mutex_unlock(&tty_mutex); +err_unref: /* after locks to avoid deadlock */ if (!IS_ERR_OR_NULL(driver)) tty_driver_kref_put(driver); diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 77703a3..d2f3c4c 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -19,6 +19,14 @@ void __lockfunc tty_lock(struct tty_struct *tty) } EXPORT_SYMBOL(tty_lock); +int tty_lock_interruptible(struct tty_struct *tty) +{ + if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty)) + return -EIO; + tty_kref_get(tty); + return mutex_lock_interruptible(&tty->legacy_mutex); +} + void __lockfunc tty_unlock(struct tty_struct *tty) { if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty)) diff --git a/include/linux/tty.h b/include/linux/tty.h index b17f759..acc53ad 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -646,6 +646,7 @@ extern long vt_compat_ioctl(struct tty_struct *tty, /* tty_mutex.c */ /* functions for preparation of BKL removal */ extern void __lockfunc tty_lock(struct tty_struct *tty); +extern int tty_lock_interruptible(struct tty_struct *tty); extern void __lockfunc tty_unlock(struct tty_struct *tty); extern void __lockfunc tty_lock_slave(struct tty_struct *tty); extern void __lockfunc tty_unlock_slave(struct tty_struct *tty); -- 2.7.0
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