tty,vcs removing con_buf/conf_buf_mtx
seems there's no longer need for using con_buf/conf_buf_mtx as vcs_read/vcs_write buffer for user's data. The do_con_write function, that was the other user of this, is currently using its own kmalloc-ed buffer. Not sure when this got changed, as I was able to find this code in 2.6.9, but it's already gone as far as current git history goes - 2.6.12-rc2. AFAICS there's a behaviour change with the current change. The lseek is not completely mutually exclusive with the vcs_read/vcs_write - the file->f_pos might get updated via lseek callback during the vcs_read/vcs_write processing. I tried to find out if the prefered behaviour is to keep this in sync within read/write/lseek functions, but I did not find any pattern on different places. I guess if user end up calling write/lseek from different threads she should know what she's doing. If needed we could use dedicated fd mutex/buffer. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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fcdba07ee3
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@ -28,7 +28,6 @@
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#include <linux/interrupt.h>
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#include <linux/interrupt.h>
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#include <linux/mm.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/init.h>
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#include <linux/mutex.h>
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#include <linux/vt_kern.h>
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#include <linux/vt_kern.h>
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#include <linux/selection.h>
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#include <linux/selection.h>
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#include <linux/kbd_kern.h>
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#include <linux/kbd_kern.h>
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@ -51,6 +50,8 @@
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#undef addr
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#undef addr
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#define HEADER_SIZE 4
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#define HEADER_SIZE 4
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#define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)
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struct vcs_poll_data {
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struct vcs_poll_data {
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struct notifier_block notifier;
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struct notifier_block notifier;
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unsigned int cons_num;
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unsigned int cons_num;
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@ -131,21 +132,45 @@ vcs_poll_data_get(struct file *file)
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return poll;
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return poll;
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}
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}
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/*
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* Returns VC for inode.
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* Must be called with console_lock.
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*/
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static struct vc_data*
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vcs_vc(struct inode *inode, int *viewed)
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{
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unsigned int currcons = iminor(inode) & 127;
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WARN_CONSOLE_UNLOCKED();
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if (currcons == 0) {
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currcons = fg_console;
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if (viewed)
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*viewed = 1;
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} else {
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currcons--;
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if (viewed)
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*viewed = 0;
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}
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return vc_cons[currcons].d;
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}
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/*
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* Returns size for VC carried by inode.
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* Must be called with console_lock.
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*/
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static int
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static int
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vcs_size(struct inode *inode)
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vcs_size(struct inode *inode)
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{
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{
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int size;
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int size;
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int minor = iminor(inode);
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int minor = iminor(inode);
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int currcons = minor & 127;
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struct vc_data *vc;
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struct vc_data *vc;
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if (currcons == 0)
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WARN_CONSOLE_UNLOCKED();
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currcons = fg_console;
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else
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vc = vcs_vc(inode, NULL);
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currcons--;
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if (!vc)
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if (!vc_cons_allocated(currcons))
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return -ENXIO;
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return -ENXIO;
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vc = vc_cons[currcons].d;
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size = vc->vc_rows * vc->vc_cols;
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size = vc->vc_rows * vc->vc_cols;
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@ -158,17 +183,13 @@ static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
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{
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{
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int size;
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int size;
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mutex_lock(&con_buf_mtx);
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console_lock();
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console_lock();
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size = vcs_size(file->f_path.dentry->d_inode);
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size = vcs_size(file->f_path.dentry->d_inode);
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console_unlock();
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console_unlock();
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if (size < 0) {
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if (size < 0)
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mutex_unlock(&con_buf_mtx);
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return size;
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return size;
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}
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switch (orig) {
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switch (orig) {
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default:
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default:
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mutex_unlock(&con_buf_mtx);
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return -EINVAL;
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return -EINVAL;
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case 2:
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case 2:
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offset += size;
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offset += size;
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@ -179,11 +200,9 @@ static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
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break;
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break;
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}
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}
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if (offset < 0 || offset > size) {
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if (offset < 0 || offset > size) {
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mutex_unlock(&con_buf_mtx);
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return -EINVAL;
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return -EINVAL;
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}
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}
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file->f_pos = offset;
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file->f_pos = offset;
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mutex_unlock(&con_buf_mtx);
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return file->f_pos;
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return file->f_pos;
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}
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}
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@ -196,12 +215,15 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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struct vc_data *vc;
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struct vc_data *vc;
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struct vcs_poll_data *poll;
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struct vcs_poll_data *poll;
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long pos;
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long pos;
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long viewed, attr, read;
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long attr, read;
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int col, maxcol;
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int col, maxcol, viewed;
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unsigned short *org = NULL;
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unsigned short *org = NULL;
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ssize_t ret;
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ssize_t ret;
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char *con_buf;
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mutex_lock(&con_buf_mtx);
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con_buf = (char *) __get_free_page(GFP_KERNEL);
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if (!con_buf)
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return -ENOMEM;
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pos = *ppos;
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pos = *ppos;
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@ -211,18 +233,10 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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console_lock();
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console_lock();
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attr = (currcons & 128);
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attr = (currcons & 128);
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currcons = (currcons & 127);
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if (currcons == 0) {
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currcons = fg_console;
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viewed = 1;
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} else {
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currcons--;
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viewed = 0;
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}
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ret = -ENXIO;
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ret = -ENXIO;
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if (!vc_cons_allocated(currcons))
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vc = vcs_vc(inode, &viewed);
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if (!vc)
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goto unlock_out;
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goto unlock_out;
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vc = vc_cons[currcons].d;
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ret = -EINVAL;
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ret = -EINVAL;
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if (pos < 0)
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if (pos < 0)
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@ -367,7 +381,7 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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ret = read;
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ret = read;
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unlock_out:
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unlock_out:
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console_unlock();
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console_unlock();
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mutex_unlock(&con_buf_mtx);
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free_page((unsigned long) con_buf);
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return ret;
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return ret;
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}
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}
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unsigned int currcons = iminor(inode);
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unsigned int currcons = iminor(inode);
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struct vc_data *vc;
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struct vc_data *vc;
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long pos;
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long pos;
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long viewed, attr, size, written;
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long attr, size, written;
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char *con_buf0;
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char *con_buf0;
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int col, maxcol;
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int col, maxcol, viewed;
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u16 *org0 = NULL, *org = NULL;
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u16 *org0 = NULL, *org = NULL;
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size_t ret;
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size_t ret;
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char *con_buf;
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mutex_lock(&con_buf_mtx);
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con_buf = (char *) __get_free_page(GFP_KERNEL);
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if (!con_buf)
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return -ENOMEM;
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pos = *ppos;
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pos = *ppos;
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@ -394,19 +411,10 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
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console_lock();
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console_lock();
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attr = (currcons & 128);
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attr = (currcons & 128);
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currcons = (currcons & 127);
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if (currcons == 0) {
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currcons = fg_console;
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viewed = 1;
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} else {
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currcons--;
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viewed = 0;
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}
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ret = -ENXIO;
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ret = -ENXIO;
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if (!vc_cons_allocated(currcons))
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vc = vcs_vc(inode, &viewed);
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if (!vc)
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goto unlock_out;
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goto unlock_out;
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vc = vc_cons[currcons].d;
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size = vcs_size(inode);
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size = vcs_size(inode);
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ret = -EINVAL;
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ret = -EINVAL;
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unlock_out:
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unlock_out:
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console_unlock();
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console_unlock();
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free_page((unsigned long) con_buf);
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mutex_unlock(&con_buf_mtx);
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return ret;
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return ret;
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}
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}
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@ -2068,18 +2068,6 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
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}
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}
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}
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}
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/* This is a temporary buffer used to prepare a tty console write
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* so that we can easily avoid touching user space while holding the
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* console spinlock. It is allocated in con_init and is shared by
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* this code and the vc_screen read/write tty calls.
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*
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* We have to allocate this statically in the kernel data section
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* since console_init (and thus con_init) are called before any
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* kernel memory allocation is available.
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*/
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char con_buf[CON_BUF_SIZE];
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DEFINE_MUTEX(con_buf_mtx);
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/* is_double_width() is based on the wcwidth() implementation by
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/* is_double_width() is based on the wcwidth() implementation by
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* Markus Kuhn -- 2007-05-26 (Unicode 5.0)
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* Markus Kuhn -- 2007-05-26 (Unicode 5.0)
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* Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
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* Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
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@ -142,14 +142,6 @@ static inline bool vt_force_oops_output(struct vc_data *vc)
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return false;
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return false;
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}
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}
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/*
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* vc_screen.c shares this temporary buffer with the console write code so that
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* we can easily avoid touching user space while holding the console spinlock.
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*/
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#define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)
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extern char con_buf[CON_BUF_SIZE];
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extern struct mutex con_buf_mtx;
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extern char vt_dont_switch;
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extern char vt_dont_switch;
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extern int default_utf8;
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extern int default_utf8;
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extern int global_cursor_default;
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extern int global_cursor_default;
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