Switch /dev/snapshot writer to sws_module_ops approach so that we
can transparently rewrite the rest of the snapshot from pages pulling
to their pushing through layers.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Nigel Cunningham <ncunningham@crca.org.au>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
---
kernel/power/user.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 105 insertions(+), 8 deletions(-)
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 20bf34c..748567d 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -66,15 +66,82 @@ static struct snapshot_data {
atomic_t snapshot_device_available = ATOMIC_INIT(1);
+static void *to_do_buf;
+static struct workqueue_struct *suspend_worker;
+static DECLARE_WAIT_QUEUE_HEAD(to_do_wait);
+static DECLARE_WAIT_QUEUE_HEAD(to_do_done);
+static DECLARE_BITMAP(to_do_flags, 10);
+
+#define TODO_WORK 1
+#define TODO_FINISH 2
+#define TODO_CLOSED 3
+#define TODO_ERROR 4
+
static unsigned long user_storage_available(void)
{
return ~0UL; /* we have no idea, maybe we will fail later */
}
+static int get_user_writer(void)
+{
+ return 0;
+}
+
+static int user_write_page(void *buf, struct bio **bio_chain)
+{
+ int err = 0;
+
+ if (test_bit(TODO_CLOSED, to_do_flags))
+ return -EIO;
+
+ to_do_buf = buf;
+ wmb();
+ set_bit(TODO_WORK, to_do_flags);
+ wake_up_interruptible(&to_do_wait);
+
+ wait_event(to_do_done, !test_bit(TODO_WORK, to_do_flags) ||
+ (err = test_bit(TODO_CLOSED, to_do_flags)));
+
+ return err ? -EIO : 0;
+}
+
+static int put_user_writer(unsigned int flags, int error)
+{
+ int err = 0;
+
+ if (error)
+ set_bit(TODO_ERROR, to_do_flags);
+ set_bit(TODO_FINISH, to_do_flags);
+ wake_up_interruptible(&to_do_wait);
+
+ wait_event(to_do_done, !test_bit(TODO_FINISH, to_do_flags) ||
+ (err = test_bit(TODO_CLOSED, to_do_flags)));
+
+ if (!error && err)
+ error = -EIO;
+
+ return error;
+}
+
struct sws_module_ops user_ops = {
...
