diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-22 19:59:04 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-22 19:59:04 -0700 |
commit | 73ecf3a6e3f0206bf56a0fefe3b3eda042fb7034 (patch) | |
tree | 866f0ebb2b148479e93b5ac955097b1cc94ceb4e /drivers/char/vc_screen.c | |
parent | b9da0571050c09863e59f94d0b8594a290d61b88 (diff) | |
parent | cd3ecad19aea8debae9a48b53de2ec7a571f24e9 (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (49 commits)
serial8250: ratelimit "too much work" error
serial: bfin_sport_uart: speed up sport RX sample rate to be 3% faster
serial: abstraction for 8250 legacy ports
serial/imx: check that the buffer is non-empty before sending it out
serial: mfd: add more baud rates support
jsm: Remove the uart port on errors
Alchemy: Add UART PM methods.
8250: allow platforms to override PM hook.
altera_uart: Don't use plain integer as NULL pointer
altera_uart: Fix missing prototype for registering an early console
altera_uart: Fixup type usage of port flags
altera_uart: Make it possible to use Altera UART and 8250 ports together
altera_uart: Add support for different address strides
altera_uart: Add support for getting mapbase and IRQ from resources
altera_uart: Add support for polling mode (IRQ-less)
serial: Factor out uart_poll_timeout() from 8250 driver
serial: mark the 8250 driver as maintained
serial: 8250: Don't delay after transmitter is ready.
tty: MAINTAINERS: add drivers/serial/jsm/ as maintained driver
vcs: invoke the vt update callback when /dev/vcs* is written to
...
Diffstat (limited to 'drivers/char/vc_screen.c')
-rw-r--r-- | drivers/char/vc_screen.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/drivers/char/vc_screen.c b/drivers/char/vc_screen.c index bcce46c96b8..273ab44cc91 100644 --- a/drivers/char/vc_screen.c +++ b/drivers/char/vc_screen.c @@ -35,6 +35,12 @@ #include <linux/console.h> #include <linux/device.h> #include <linux/smp_lock.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/poll.h> +#include <linux/signal.h> +#include <linux/slab.h> +#include <linux/notifier.h> #include <asm/uaccess.h> #include <asm/byteorder.h> @@ -45,6 +51,86 @@ #undef addr #define HEADER_SIZE 4 +struct vcs_poll_data { + struct notifier_block notifier; + unsigned int cons_num; + bool seen_last_update; + wait_queue_head_t waitq; + struct fasync_struct *fasync; +}; + +static int +vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param) +{ + struct vt_notifier_param *param = _param; + struct vc_data *vc = param->vc; + struct vcs_poll_data *poll = + container_of(nb, struct vcs_poll_data, notifier); + int currcons = poll->cons_num; + + if (code != VT_UPDATE) + return NOTIFY_DONE; + + if (currcons == 0) + currcons = fg_console; + else + currcons--; + if (currcons != vc->vc_num) + return NOTIFY_DONE; + + poll->seen_last_update = false; + wake_up_interruptible(&poll->waitq); + kill_fasync(&poll->fasync, SIGIO, POLL_IN); + return NOTIFY_OK; +} + +static void +vcs_poll_data_free(struct vcs_poll_data *poll) +{ + unregister_vt_notifier(&poll->notifier); + kfree(poll); +} + +static struct vcs_poll_data * +vcs_poll_data_get(struct file *file) +{ + struct vcs_poll_data *poll = file->private_data; + + if (poll) + return poll; + + poll = kzalloc(sizeof(*poll), GFP_KERNEL); + if (!poll) + return NULL; + poll->cons_num = iminor(file->f_path.dentry->d_inode) & 127; + init_waitqueue_head(&poll->waitq); + poll->notifier.notifier_call = vcs_notifier; + if (register_vt_notifier(&poll->notifier) != 0) { + kfree(poll); + return NULL; + } + + /* + * This code may be called either through ->poll() or ->fasync(). + * If we have two threads using the same file descriptor, they could + * both enter this function, both notice that the structure hasn't + * been allocated yet and go ahead allocating it in parallel, but + * only one of them must survive and be shared otherwise we'd leak + * memory with a dangling notifier callback. + */ + spin_lock(&file->f_lock); + if (!file->private_data) { + file->private_data = poll; + } else { + /* someone else raced ahead of us */ + vcs_poll_data_free(poll); + poll = file->private_data; + } + spin_unlock(&file->f_lock); + + return poll; +} + static int vcs_size(struct inode *inode) { @@ -102,6 +188,7 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) struct inode *inode = file->f_path.dentry->d_inode; unsigned int currcons = iminor(inode); struct vc_data *vc; + struct vcs_poll_data *poll; long pos; long viewed, attr, read; int col, maxcol; @@ -134,6 +221,9 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) ret = -EINVAL; if (pos < 0) goto unlock_out; + poll = file->private_data; + if (count && poll) + poll->seen_last_update = true; read = 0; ret = 0; while (count) { @@ -448,6 +538,8 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) } *ppos += written; ret = written; + if (written) + vcs_scr_updated(vc); unlock_out: release_console_sem(); @@ -457,6 +549,37 @@ unlock_out: return ret; } +static unsigned int +vcs_poll(struct file *file, poll_table *wait) +{ + struct vcs_poll_data *poll = vcs_poll_data_get(file); + int ret = 0; + + if (poll) { + poll_wait(file, &poll->waitq, wait); + if (!poll->seen_last_update) + ret = POLLIN | POLLRDNORM; + } + return ret; +} + +static int +vcs_fasync(int fd, struct file *file, int on) +{ + struct vcs_poll_data *poll = file->private_data; + + if (!poll) { + /* don't allocate anything if all we want is disable fasync */ + if (!on) + return 0; + poll = vcs_poll_data_get(file); + if (!poll) + return -ENOMEM; + } + + return fasync_helper(fd, file, on, &poll->fasync); +} + static int vcs_open(struct inode *inode, struct file *filp) { @@ -470,11 +593,23 @@ vcs_open(struct inode *inode, struct file *filp) return ret; } +static int vcs_release(struct inode *inode, struct file *file) +{ + struct vcs_poll_data *poll = file->private_data; + + if (poll) + vcs_poll_data_free(poll); + return 0; +} + static const struct file_operations vcs_fops = { .llseek = vcs_lseek, .read = vcs_read, .write = vcs_write, + .poll = vcs_poll, + .fasync = vcs_fasync, .open = vcs_open, + .release = vcs_release, }; static struct class *vc_class; |