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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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