From febde3711992a64ea83a47a719f68a90c4b0927a Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Date: Tue, 14 Oct 2008 05:02:09 +0000 Subject: hvc_console: Add support for tty window resizing The patch provides the hvc_resize() function to update the terminal window dimensions (struct winsize) for a specified hvc console. The function stores the new window size and schedules a function that finally updates the tty winsize and signals the change to user space (SIGWINCH). Because the winsize update must acquire a mutex and might sleep, the function is scheduled instead of being called from hvc_poll() or khvcd. This patch uses the tty_do_resize() routine from the tty layer. A pending resize work is canceled in hvc_close() and hvc_hangup(). Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- drivers/char/hvc_console.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++ drivers/char/hvc_console.h | 6 +++++ 2 files changed, 64 insertions(+) diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c index 3650c904401..2d256dc8052 100644 --- a/drivers/char/hvc_console.c +++ b/drivers/char/hvc_console.c @@ -374,6 +374,9 @@ static void hvc_close(struct tty_struct *tty, struct file * filp) if (hp->ops->notifier_del) hp->ops->notifier_del(hp, hp->data); + /* cancel pending tty resize work */ + cancel_work_sync(&hp->tty_resize); + /* * Chain calls chars_in_buffer() and returns immediately if * there is no buffered data otherwise sleeps on a wait queue @@ -399,6 +402,9 @@ static void hvc_hangup(struct tty_struct *tty) if (!hp) return; + /* cancel pending tty resize work */ + cancel_work_sync(&hp->tty_resize); + spin_lock_irqsave(&hp->lock, flags); /* @@ -494,6 +500,39 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count return written; } +/** + * hvc_set_winsz() - Resize the hvc tty terminal window. + * @work: work structure. + * + * The routine shall not be called within an atomic context because it + * might sleep. + * + * Locking: hp->lock + */ +static void hvc_set_winsz(struct work_struct *work) +{ + struct hvc_struct *hp; + unsigned long hvc_flags; + struct tty_struct *tty; + struct winsize ws; + + hp = container_of(work, struct hvc_struct, tty_resize); + if (!hp) + return; + + spin_lock_irqsave(&hp->lock, hvc_flags); + if (!hp->tty) { + spin_unlock_irqrestore(&hp->lock, hvc_flags); + return; + } + ws = hp->ws; + tty = tty_kref_get(hp->tty); + spin_unlock_irqrestore(&hp->lock, hvc_flags); + + tty_do_resize(tty, tty, &ws); + tty_kref_put(tty); +} + /* * This is actually a contract between the driver and the tty layer outlining * how much write room the driver can guarantee will be sent OR BUFFERED. This @@ -638,6 +677,24 @@ int hvc_poll(struct hvc_struct *hp) } EXPORT_SYMBOL_GPL(hvc_poll); +/** + * hvc_resize() - Update terminal window size information. + * @hp: HVC console pointer + * @ws: Terminal window size structure + * + * Stores the specified window size information in the hvc structure of @hp. + * The function schedule the tty resize update. + * + * Locking: Locking free; the function MUST be called holding hp->lock + */ +void hvc_resize(struct hvc_struct *hp, struct winsize ws) +{ + if ((hp->ws.ws_row != ws.ws_row) || (hp->ws.ws_col != ws.ws_col)) { + hp->ws = ws; + schedule_work(&hp->tty_resize); + } +} + /* * This kthread is either polling or interrupt driven. This is determined by * calling hvc_poll() who determines whether a console adapter support @@ -720,6 +777,7 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int data, kref_init(&hp->kref); + INIT_WORK(&hp->tty_resize, hvc_set_winsz); spin_lock_init(&hp->lock); spin_lock(&hvc_structs_lock); diff --git a/drivers/char/hvc_console.h b/drivers/char/hvc_console.h index ec0e9bb0e5e..e3359f3c9b2 100644 --- a/drivers/char/hvc_console.h +++ b/drivers/char/hvc_console.h @@ -27,6 +27,7 @@ #ifndef HVC_CONSOLE_H #define HVC_CONSOLE_H #include <linux/kref.h> +#include <linux/tty.h> /* * This is the max number of console adapters that can/will be found as @@ -56,6 +57,8 @@ struct hvc_struct { struct hv_ops *ops; int irq_requested; int data; + struct winsize ws; + struct work_struct tty_resize; struct list_head next; struct kref kref; /* ref count & hvc_struct lifetime */ }; @@ -84,6 +87,9 @@ extern int __devexit hvc_remove(struct hvc_struct *hp); int hvc_poll(struct hvc_struct *hp); void hvc_kick(void); +/* Resize hvc tty terminal window */ +extern void hvc_resize(struct hvc_struct *hp, struct winsize ws); + /* default notifier for irq based notification */ extern int notifier_add_irq(struct hvc_struct *hp, int data); extern void notifier_del_irq(struct hvc_struct *hp, int data); -- cgit v1.2.3-70-g09d2