PM / Hibernate: Snapshot cleanup
Remove support of reads with offset. This means snapshot_read/write_next
now does not accept count parameter. It allows to clean up the functions
and snapshot handle which no longer needs to care about offsets.
/dev/snapshot handler is converted to simple_{read_from,write_to}_buffer
which take care of offsets.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/kernel/power/user.c b/kernel/power/user.c
index a8c9621..e819e17 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -151,6 +151,7 @@
{
struct snapshot_data *data;
ssize_t res;
+ loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
@@ -159,14 +160,19 @@
res = -ENODATA;
goto Unlock;
}
- res = snapshot_read_next(&data->handle, count);
- if (res > 0) {
- if (copy_to_user(buf, data_of(data->handle), res))
- res = -EFAULT;
- else
- *offp = data->handle.offset;
+ if (!pg_offp) { /* on page boundary? */
+ res = snapshot_read_next(&data->handle);
+ if (res <= 0)
+ goto Unlock;
+ } else {
+ res = PAGE_SIZE - pg_offp;
}
+ res = simple_read_from_buffer(buf, count, &pg_offp,
+ data_of(data->handle), res);
+ if (res > 0)
+ *offp += res;
+
Unlock:
mutex_unlock(&pm_mutex);
@@ -178,18 +184,25 @@
{
struct snapshot_data *data;
ssize_t res;
+ loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
data = filp->private_data;
- res = snapshot_write_next(&data->handle, count);
- if (res > 0) {
- if (copy_from_user(data_of(data->handle), buf, res))
- res = -EFAULT;
- else
- *offp = data->handle.offset;
+
+ if (!pg_offp) {
+ res = snapshot_write_next(&data->handle);
+ if (res <= 0)
+ goto unlock;
+ } else {
+ res = PAGE_SIZE - pg_offp;
}
+ res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
+ buf, count);
+ if (res > 0)
+ *offp += res;
+unlock:
mutex_unlock(&pm_mutex);
return res;
