[RFC 08/15] PM / Hibernate: add user module_ops

[Jiri Slaby]

Add sws_module_ops into /dev/snapshot user interface, so far only with
.storage_available. The structure will be shortly filled while converting
it to ops.

Also, when using this interface, switch to the ops on open/release.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Nigel Cunningham <ncunningham@xxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
---
 kernel/power/user.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 68a99c1..20bf34c 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -61,10 +61,20 @@ static struct snapshot_data {
 	char frozen;
 	char ready;
 	char platform_support;
+	struct sws_module_ops *prev_ops;
 } snapshot_state;
 
 atomic_t snapshot_device_available = ATOMIC_INIT(1);
 
+static unsigned long user_storage_available(void)
+{
+	return ~0UL; /* we have no idea, maybe we will fail later */
+}
+
+struct sws_module_ops user_ops = {
+	.storage_available = user_storage_available,
+};
+
 static int snapshot_open(struct inode *inode, struct file *filp)
 {
 	struct snapshot_data *data;
@@ -115,6 +125,10 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 	}
 	if (error)
 		atomic_inc(&snapshot_device_available);
+	else {
+		data->prev_ops = sws_io_ops;
+		sws_io_ops = &user_ops;
+	}
 	data->frozen = 0;
 	data->ready = 0;
 	data->platform_support = 0;
@@ -139,6 +153,7 @@ static int snapshot_release(struct inode *inode, struct file *filp)
 		thaw_processes();
 	pm_notifier_call_chain(data->mode == O_WRONLY ?
 			PM_POST_HIBERNATION : PM_POST_RESTORE);
+	sws_io_ops = data->prev_ops;
 	atomic_inc(&snapshot_device_available);
 
 	mutex_unlock(&pm_mutex);
-- 
1.7.0.2


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