[PATCH 1/5] btrfs: Factor out reada loop in __reada_start_machine

[Nikolay Borisov <nborisov@xxxxxxxx>]

This is in preparation for moving fs_devices to proper lists.

Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
---
 fs/btrfs/reada.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 243a2e44526e..aa9d24ed56d7 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -767,15 +767,14 @@ static void reada_start_machine_worker(struct btrfs_work *work)
 	kfree(rmw);
 }
 
-static void __reada_start_machine(struct btrfs_fs_info *fs_info)
+
+/* Try to start up to 10k READA requests for a group of devices. */
+static int __reada_start_for_fsdevs(struct btrfs_fs_devices *fs_devices)
 {
-	struct btrfs_device *device;
-	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	u64 enqueued;
 	u64 total = 0;
-	int i;
+	struct btrfs_device *device;
 
-again:
 	do {
 		enqueued = 0;
 		mutex_lock(&fs_devices->device_list_mutex);
@@ -787,6 +786,18 @@ static void __reada_start_machine(struct btrfs_fs_info *fs_info)
 		mutex_unlock(&fs_devices->device_list_mutex);
 		total += enqueued;
 	} while (enqueued && total < 10000);
+
+	return total;
+}
+
+static void __reada_start_machine(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+	int i;
+	u64 enqueued = 0;
+
+again:
+	enqueued += __reada_start_for_fsdevs(fs_devices);
 	if (fs_devices->seed) {
 		fs_devices = fs_devices->seed;
 		goto again;
-- 
2.17.1