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authorBen Hutchings <ben@decadent.org.uk>2014-05-19 00:56:22 +0100
committerShow Liu <show.liu@linaro.org>2014-06-18 12:05:26 +0800
commit2e5d43de98c5a3d92aa038ae7ac23ab50d0de244 (patch)
tree92d6b16aafdf65f08d1cc4ca64bf60b2d49d083b
parent4d471eeec0beb010e2278c70bcfed91818c5e055 (diff)
downloadlinaro-lsk-2e5d43de98c5a3d92aa038ae7ac23ab50d0de244.tar.gz
Staging: speakup: Move pasting into a work item
commit d7500135802ca55b3f4e01a16544e8b34082f8c3 upstream. Input is handled in softirq context, but when pasting we may need to sleep. speakup_paste_selection() currently tries to bodge this by busy-waiting if in_atomic(), but that doesn't help because the ldisc may also sleep. For bonus breakage, speakup_paste_selection() changes the state of current, even though it's not running in process context. Move it into a work item and make sure to cancel it on exit. References: https://bugs.debian.org/735202 References: https://bugs.debian.org/744015 Reported-by: Paul Gevers <elbrus@debian.org> Reported-and-tested-by: Jarek Czekalski <jarekczek@poczta.onet.pl> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/staging/speakup/main.c1
-rw-r--r--drivers/staging/speakup/selection.c38
-rw-r--r--drivers/staging/speakup/speakup.h1
3 files changed, 34 insertions, 6 deletions
diff --git a/drivers/staging/speakup/main.c b/drivers/staging/speakup/main.c
index ef5933b9359..f61f9cf95ed 100644
--- a/drivers/staging/speakup/main.c
+++ b/drivers/staging/speakup/main.c
@@ -2218,6 +2218,7 @@ static void __exit speakup_exit(void)
unregister_keyboard_notifier(&keyboard_notifier_block);
unregister_vt_notifier(&vt_notifier_block);
speakup_unregister_devsynth();
+ speakup_cancel_paste();
del_timer(&cursor_timer);
kthread_stop(speakup_task);
speakup_task = NULL;
diff --git a/drivers/staging/speakup/selection.c b/drivers/staging/speakup/selection.c
index f0fb00392d6..f67941e78e4 100644
--- a/drivers/staging/speakup/selection.c
+++ b/drivers/staging/speakup/selection.c
@@ -4,6 +4,8 @@
#include <linux/sched.h>
#include <linux/device.h> /* for dev_warn */
#include <linux/selection.h>
+#include <linux/workqueue.h>
+#include <asm/cmpxchg.h>
#include "speakup.h"
@@ -121,20 +123,24 @@ int speakup_set_selection(struct tty_struct *tty)
return 0;
}
-/* TODO: move to some helper thread, probably. That'd fix having to check for
- * in_atomic(). */
-int speakup_paste_selection(struct tty_struct *tty)
+struct speakup_paste_work {
+ struct work_struct work;
+ struct tty_struct *tty;
+};
+
+static void __speakup_paste_selection(struct work_struct *work)
{
+ struct speakup_paste_work *spw =
+ container_of(work, struct speakup_paste_work, work);
+ struct tty_struct *tty = xchg(&spw->tty, NULL);
struct vc_data *vc = (struct vc_data *) tty->driver_data;
int pasted = 0, count;
DECLARE_WAITQUEUE(wait, current);
+
add_wait_queue(&vc->paste_wait, &wait);
while (sel_buffer && sel_buffer_lth > pasted) {
set_current_state(TASK_INTERRUPTIBLE);
if (test_bit(TTY_THROTTLED, &tty->flags)) {
- if (in_atomic())
- /* if we are in an interrupt handler, abort */
- break;
schedule();
continue;
}
@@ -146,6 +152,26 @@ int speakup_paste_selection(struct tty_struct *tty)
}
remove_wait_queue(&vc->paste_wait, &wait);
current->state = TASK_RUNNING;
+ tty_kref_put(tty);
+}
+
+static struct speakup_paste_work speakup_paste_work = {
+ .work = __WORK_INITIALIZER(speakup_paste_work.work,
+ __speakup_paste_selection)
+};
+
+int speakup_paste_selection(struct tty_struct *tty)
+{
+ if (cmpxchg(&speakup_paste_work.tty, NULL, tty) != NULL)
+ return -EBUSY;
+
+ tty_kref_get(tty);
+ schedule_work_on(WORK_CPU_UNBOUND, &speakup_paste_work.work);
return 0;
}
+void speakup_cancel_paste(void)
+{
+ cancel_work_sync(&speakup_paste_work.work);
+ tty_kref_put(speakup_paste_work.tty);
+}
diff --git a/drivers/staging/speakup/speakup.h b/drivers/staging/speakup/speakup.h
index 0126f714821..74fe72429b2 100644
--- a/drivers/staging/speakup/speakup.h
+++ b/drivers/staging/speakup/speakup.h
@@ -77,6 +77,7 @@ extern void synth_buffer_clear(void);
extern void speakup_clear_selection(void);
extern int speakup_set_selection(struct tty_struct *tty);
extern int speakup_paste_selection(struct tty_struct *tty);
+extern void speakup_cancel_paste(void);
extern void speakup_register_devsynth(void);
extern void speakup_unregister_devsynth(void);
extern void synth_write(const char *buf, size_t count);