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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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3.6 kB · 141 lines
C
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142// 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);}