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// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h> /* for kmalloc */
#include <linux/consolemap.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/device.h> /* for dev_warn */
#include <linux/selection.h>
#include <linux/workqueue.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/atomic.h>
#include <linux/console.h>
#include "speakup.h"
unsigned short spk_xs, spk_ys, spk_xe, spk_ye; /* our region points */
struct vc_data *spk_sel_cons;
struct speakup_selection_work {
struct work_struct work;
struct tiocl_selection sel;
struct tty_struct *tty;
};
static void __speakup_set_selection(struct work_struct *work)
{
struct speakup_selection_work *ssw =
container_of(work, struct speakup_selection_work, work);
struct tty_struct *tty;
struct tiocl_selection sel;
sel = ssw->sel;
/* this ensures we copy sel before releasing the lock below */
rmb();
/* release the lock by setting tty of the struct to NULL */
tty = xchg(&ssw->tty, NULL);
if (spk_sel_cons != vc_cons[fg_console].d) {
spk_sel_cons = vc_cons[fg_console].d;
pr_warn("Selection: mark console not the same as cut\n");
goto unref;
}
console_lock();
clear_selection();
console_unlock();
set_selection_kernel(&sel, tty);
unref:
tty_kref_put(tty);
}
static struct speakup_selection_work speakup_sel_work = {
.work = __WORK_INITIALIZER(speakup_sel_work.work,
__speakup_set_selection)
};
int speakup_set_selection(struct tty_struct *tty)
{
/* we get kref here first in order to avoid a subtle race when
* cancelling selection work. getting kref first establishes the
* invariant that if speakup_sel_work.tty is not NULL when
* speakup_cancel_selection() is called, it must be the case that a put
* kref is pending.
*/
tty_kref_get(tty);
if (cmpxchg(&speakup_sel_work.tty, NULL, tty)) {
tty_kref_put(tty);
return -EBUSY;
}
/* now we have the 'lock' by setting tty member of
* speakup_selection_work. wmb() ensures that writes to
* speakup_sel_work don't happen before cmpxchg() above.
*/
wmb();
speakup_sel_work.sel.xs = spk_xs + 1;
speakup_sel_work.sel.ys = spk_ys + 1;
speakup_sel_work.sel.xe = spk_xe + 1;
speakup_sel_work.sel.ye = spk_ye + 1;
speakup_sel_work.sel.sel_mode = TIOCL_SELCHAR;
schedule_work_on(WORK_CPU_UNBOUND, &speakup_sel_work.work);
return 0;
}
void speakup_cancel_selection(void)
{
struct tty_struct *tty;
cancel_work_sync(&speakup_sel_work.work);
/* setting to null so that if work fails to run and we cancel it,
* we can run it again without getting EBUSY forever from there on.
* we need to use xchg here to avoid race with speakup_set_selection()
*/
tty = xchg(&speakup_sel_work.tty, NULL);
if (tty)
tty_kref_put(tty);
}
static void __speakup_paste_selection(struct work_struct *work)
{
struct speakup_selection_work *ssw =
container_of(work, struct speakup_selection_work, work);
struct tty_struct *tty = xchg(&ssw->tty, NULL);
paste_selection(tty);
tty_kref_put(tty);
}
static struct speakup_selection_work speakup_paste_work = {
.work = __WORK_INITIALIZER(speakup_paste_work.work,
__speakup_paste_selection)
};
int speakup_paste_selection(struct tty_struct *tty)
{
tty_kref_get(tty);
if (cmpxchg(&speakup_paste_work.tty, NULL, tty)) {
tty_kref_put(tty);
return -EBUSY;
}
schedule_work_on(WORK_CPU_UNBOUND, &speakup_paste_work.work);
return 0;
}
void speakup_cancel_paste(void)
{
struct tty_struct *tty;
cancel_work_sync(&speakup_paste_work.work);
tty = xchg(&speakup_paste_work.tty, NULL);
if (tty)
tty_kref_put(tty);
}
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